Oil Types, High Mileage Motor Oils, and Ideal Oil Change Intervals

[Oilblivion]

Hello fellow BITOG members!

I'm Chris, and I've been around cars for most of my life. However, I have a few questions on certain aspects of engine oils that I'd love your input on. It's always great to get a range of perspectives from the wealth of knowledge on this forum.

• Conventional vs. Synthetic Oil: I understand that there's been a considerable shift from conventional to synthetic oils over the past couple of decades. The science of it still eludes me though, so I'm hoping someone could clarify what the actual benefits and upsides are for each type.
  
  From what I've read, conventional oil comes from refined crude oil and is suitable for normal, everyday driving conditions. It's cheaper and gets the job done. On the other hand, synthetic oil, created through a synthetic process, seems to be resistant to high temperatures, provides better engine protection and performance, and flows better in cold temperatures. It's more expensive, though. I'm wondering if there are more specific benefits or drawbacks to each that I should consider?
  
  
• High Mileage Motor Oils and Seal Conditioners: Now, this is something I've always wondered about. How exactly are high mileage motor oils made differently compared to their regular counterparts, and what are these "seal conditioners" they often mention?
  
  My guess is that high mileage oils have additives that help preserve and protect the engine components, but I'd love to know more. Are there significant benefits to switching to high mileage oil once your vehicle crosses a certain mileage?
  
  
• Oil Change Interval: Lastly, I'm curious about the ideal oil change interval. I know that the common recommendation is every 3,000 to 5,000 miles for conventional oil and 7,500 to 10,000 miles for synthetic. But what if our primary concern is maximum wear protection and engine longevity? Would the interval be different in this case?

Thanks so much in advance for any insights you can share on these topics. I'm looking forward to learning from all of you!

Chris

 

[FCD]

I'd advise you to start by reading through this :

Motor Oil 101 - Chapter One - Operating Temperatures and Viscosity - Bob is the Oil Guy

Chapter One Understanding what viscosity grades mean can be confusing. The average driver just tries to follow what is in the owner’s manual – this is a good practice. Some owner’s manuals allow for different grades based on the predicted operating temperature. For example, they may specify a...

bobistheoilguy.com

 

[Oilblivion]

I'd advise you to start by reading through this :

Motor Oil 101 - Chapter One - Operating Temperatures and Viscosity - Bob is the Oil Guy

Chapter One Understanding what viscosity grades mean can be confusing. The average driver just tries to follow what is in the owner’s manual – this is a good practice. Some owner’s manuals allow for different grades based on the predicted operating temperature. For example, they may specify a...

bobistheoilguy.com

I did, even took notes:

Chapter 1

• Viscosity is a fluid's resistance to flow. High viscosity fluids don't flow easily, and low viscosity fluids flow easily.
• Engine oils used to be simple refined fluids, with different oils having different flow rates, denoted by letters A, B, C. The Society of Automotive Engineers (SAE) later introduced a numerical system.
• Modern engine oils have various additives to modify their behavior with changing temperatures, complicating the grading system.
• Most people think that oil thins out when it gets hot and that is the issue. But, the real problem is oil thickening when it cools.
• 90% of engine wear is said to occur at startup, which is mostly due to oil's increased viscosity (thickness) at lower temperatures.
• Oil thickness increases as the temperature decreases. For instance, oil with a viscosity of 10cSt at 212F could become 100cSt at 104F, and 250cSt at 32F.
• In very cold conditions, oil can thicken so much that it cannot lubricate the engine properly, leading to increased wear and possible engine failure.
• A simple solution might be to maintain oil at a constant viscosity (e.g., 10cSt) but that won't work because as the engine gets hotter, such oil would be too thin.
• We need an oil with the right operating temperature viscosity that does not thicken too much in cold start-up temperatures and does not thin out too much as the engine heats up.
• Multi-grade oil is the solution to this problem, designed to maintain a relatively stable viscosity across a range of temperatures.

Chapter 2

• An engine oil with lower viscosity at startup (e.g., 40cSt at 104F) is better than an oil with higher viscosity at the same temperature (e.g., 100cSt at 104F) because it will flow better and waste less energy.
• The oil grade (e.g., 5W30) on the store's product is based on SAE J300, which reflects how the viscosity changes with temperature.
• The oil grade XWYY is made up of two parts: the first part (XW) represents cold temperature performance and the second part (YY) represents high temperature performance.
• For cold temperature performance, ratings are 0W, 5W, 10W, 15W, 20W, and 25W, where lower numbers represent better flow at cold temperatures.
• For high temperature performance, ratings are 8, 12, 16, 20, 30, 40, 50, and 60, with higher numbers indicating better viscosity at high temperatures.
• For instance, 5W30 oil has certain cold and high temperature performance characteristics. Oils labeled as 0W30, 5W30, or 10W30 have similar high temperature performance, but different cold temperature performance.
• In our previous 10cSt example, the oil fits into the 30 category of the high temperature performance scale, so it's an XW30 oil.
• Oils such as 0W30 and 10W30 have similar performance at operating temperature, but the 0W30 oil has better performance (lower viscosity) at startup.
• Most engine wear occurs at startup when the oil is too thick. For example, at 75F startup temperature, a 10W30 oil would be thicker than a 0W30 oil.
• Even though both oils reach the desired viscosity at operating temperature, the 0W30 oil doesn't have to change its viscosity as much as the 10W30 oil during startup.
• The difference in startup and operating performance for two oils with different cold temperature grades but same high temperature grade is due to the way the oil is manufactured.

Chapter 3

• Today's engine oil is composed of several components including the base oil mix, viscosity modifying additives, and other additives aimed at preventing wear, cleaning the engine, and extending oil drain intervals.
• Viscosity modifiers or Viscosity Index Improvers (VII) are used to adjust how the final oil blend responds to temperature changes. This enables the creation of different oil grades like 0W30, 5W30, 10W30, etc.
• The right viscosity at operating temperature is achieved by selecting a mix of base oils and a VII to hit the desired grade target. The mix could differ based on several reasons such as better low temperature performance, cost, or other manufacturing considerations.
• Some viscosity modifiers can wear out over time, leading to the thinning of the oil. This wear is usually not significant in normal engines running under everyday conditions.
• There are Pour Point Depressants (PPDs), a class of viscosity modifiers, that prevent the formation of wax crystals as the temperature drops. This helps improve the cold temperature performance of the oil.
• Oil can thin out due to fuel dilution and the wearing out of VIIs, but it can also thicken from oxidation, leading to varnish and sludge formation. Regular oil changes can prevent excessive oxidation.
• Oil volatility can also lead to thickening as lighter fractions of the oil evaporate, leaving behind higher viscosity oils. Oil manufacturers balance the need for lower viscosity oils with the risk of evaporation.
• Viscosity is influenced not just by temperature but also by load and shear forces. Engine oils can thin out under high shear forces, a phenomenon useful at low temperatures but potentially problematic at high temperatures. This is why there's a minimum High-Temperature High Shear (HTHS) requirement for each oil grade.
• Engine manufacturers now recommend lighter oils to improve fuel economy. These oils reach their operational viscosity window faster, consuming less energy.
• Engine oils are being optimized for lower and lower viscosities with engines being designed to run on lower viscosity oils at operating temperature, necessitating more complex oil formulas and better quality base oils. This is where synthetic oils come into play.

Chapter 4

• Synthetic oils are often recommended for high-performance cars due to their benefits over conventional oils. They tend to oxidize slower, extending the oil change interval, and maintain operational viscosity better across temperature changes.
• Synthetic oils don't thicken as much as conventional oils at lower temperatures, offering better cold temperature performance. This can lead to reduced wear and energy waste during start-up.
• Due to their flexibility, synthetic oils can be adjusted to create higher performing products suitable for new engine technologies, including turbochargers that operate at higher speeds and temperatures.
• Synthetic oils perform significantly better in extremely cold temperatures compared to mineral oils. An example is provided where an engine using synthetic Mobil 1 oil turned over at 152 RPM in ice-cold conditions, compared to mineral oils (10W-30 and 10W-40) which turned over at 45 and 32 RPM, respectively.
• Synthetic oils are also more resistant to oxidation and volatility, thereby reducing oil thickening over time. This resistance means synthetic oils can endure longer oil drain intervals and harsher conditions than mineral oils.
• Most synthetic and conventional oils are compatible, meaning one can switch back and forth without issues. The idea that you must stick with synthetics once you start using them is a myth.
• While synthetic oils can offer significant advantages, their use isn't necessary for all drivers. Both synthetic and conventional oils have a variety of users.
• Brand choice doesn't necessarily matter, as there is a lot of competition in the oil manufacturing industry. However, some car manufacturers recommend specific brands as they design and test their engines with those products.
• If choosing an oil, one should check the owner's manual, ensure the correct viscosity grade is selected, consider cold temperature performance, and learn about the different specifications and applications for which oils are designed.

Chapter 5

• Engine oil is a complex blend of components that serve several key functions including enhancing performance, offering protection, and improving fuel economy.
• Engine oils are made thinner to reduce energy consumption and improve fuel economy. This is achieved by bringing the oil closer to its optimal operational viscosity at startup, which requires less energy to heat the oil and make it thinner.
• The viscosity of engine oil can also be modified according to the shear rate of engine components. For instance, in high shear environments, the oil can temporarily thin out to facilitate better flow.
• Additives in engine oil can reduce friction, thus aiding in improving fuel economy.
• Additives also provide wear protection by creating a protective layer on engine parts, preventing metal from wearing away and thus prolonging engine component life.
• Engine oil additives also contribute to engine cleanliness. Additives like detergents and dispersants help clean off deposits from surfaces and keep them trapped in the oil to be removed by the oil filter or during oil change.
• Synthetic oils and anti-oxidants can help combat oil oxidation which can contribute to deposits and varnish, thus keeping engines cleaner for longer.
• Oil makers need to ensure compatibility with various engine materials, considering different parts of the engine may react differently to synthetic oils, mineral oils, and their additives.
• Problems like leaking engine seals that were initially associated with synthetic oils have been solved through a combination of changes in seal materials and the inclusion of ingredients in the oil blend that prevent the issue.
• Learning about engine oil can help in better vehicle maintenance, extending engine life, and improving fuel economy.
• Participating in communities like the Bob is the Oil Guy Forums can help expand knowledge on engine oils and their attributes.

Chapter 6

• The article primarily discusses the process of choosing the right engine oil for your car, highlighting that it's a decision dependent on various factors, including car make and model, driving habits, and climate.
• The factors most people consider while choosing an engine oil are:
  • Brand: Selecting a reputable brand, known for quality.
  • Grade: Choosing the viscosity grade as recommended by the Original Equipment Manufacturer (OEM).
  • Trust: Often people choose brands they trust, or ones recommended by someone they trust.
  • Specifications: Paying attention to key specifications related to the car and oil, such as API (American Petroleum Institute) certification, Dexos1 for GM vehicles, ACEA for European vehicles, and specific certifications for brands like BMW, VW, and MB.
• Other types of oils to consider are:
  • Semi-Synthetic or Synthetic Blend: A mixture of synthetic and conventional base oils.
  • High-Mileage Oils: Specially formulated for vehicles that have been driven a lot.
  • Racing oils: Used for short-term intense operating conditions, but not necessarily suitable for everyday use.
• The oil change interval depends on the OEM recommendation, driving habits, and type of oil used. However, it can be as frequent as every 3000 miles or as infrequent as every 10000 miles.
• DIY vs professional oil change: Either method is acceptable as long as you trust the individual or company doing the change and they use the oil you prefer.
• When asking for advice on forums like BITOG, it's recommended to provide details about your vehicle, driving habits, location, and any specific preferences or problems your car might have.
• For more technical users, they can get their oil evaluated over its lifespan by visiting the Used Oil Analysis forum on BITOG.

Chapter 7

• The "W" in oil like 10W-30 doesn't stand for "winter", it is a designation of one type of testing versus another.
• The oil viscosity is dependent on temperature, with higher grade oils (e.g., 60) having higher viscosity at the same temperature compared to lower grade oils (e.g., 20).
• Over the years, the American Petroleum Institute (API) and the Society of Automotive Engineers (SAE) have improved engine oil performance with ratings from SA to SM (as of 2010).
• Moving from SJ to SL rating brings significant improvements in multiple aspects such as maximum cam plus lifter wear, sludge buildup, varnish rating, high temperature deposits, and high temperature volatility.
• The pumping viscosity of the oil is crucial for engine operation at low temperatures. Some oils, particularly SAE 10W-30 and 10W-40, have experienced failures in field due to oil forming gel structures at low temperatures.
• Tests designed for oils are made to mimic real-life conditions.
• The author recommends using highest rated motor oil available, regardless of the vehicle age or condition. Even for older engines requiring a thicker grade, it should be SL or SM rated.
• SH, SJ, and SL ratings were introduced in 1993, 1997, and 2001 respectively. According to ASTM D 4485, SL rated oils are superior and can be used in all vehicles requiring SJ and all earlier categories.
• There's a concern about SM oils having less Zinc DialkylDithioPhosphate (ZDDP) than SL and older oils. However, the usage of ZDDP was due to its low cost and multiple functions rather than superior performance. Some newer oils do not contain ZDDP and still perform excellently.
• Too much ZDDP can actually be corrosive and increase wear. A level of 0.03 is sufficient for proper function.
• The author provided links to the American Society for Testing and Materials, Society of Automotive Engineers, and the American Petroleum Institute for further information.

If you haven't read the articles yourself, you're more than welcome to read my notes above. I thought that the topics I brought up in this thread might merit some consideration.

Thank you.

 

[Cujet]

UOA results can be very helpful in determining OCI's. But do not make the mistake that you can determine engine wear rates with UOA results.

 

[4WD]

Welcome ️️

 

[kschachn]

I did, even took notes:

Chapter 1

• Viscosity is a fluid's resistance to flow. High viscosity fluids don't flow easily, and low viscosity fluids flow easily.
• Engine oils used to be simple refined fluids, with different oils having different flow rates, denoted by letters A, B, C. The Society of Automotive Engineers (SAE) later introduced a numerical system.
• Modern engine oils have various additives to modify their behavior with changing temperatures, complicating the grading system.
• Most people think that oil thins out when it gets hot and that is the issue. But, the real problem is oil thickening when it cools.
• 90% of engine wear is said to occur at startup, which is mostly due to oil's increased viscosity (thickness) at lower temperatures.
• Oil thickness increases as the temperature decreases. For instance, oil with a viscosity of 10cSt at 212F could become 100cSt at 104F, and 250cSt at 32F.
• In very cold conditions, oil can thicken so much that it cannot lubricate the engine properly, leading to increased wear and possible engine failure.
• A simple solution might be to maintain oil at a constant viscosity (e.g., 10cSt) but that won't work because as the engine gets hotter, such oil would be too thin.
• We need an oil with the right operating temperature viscosity that does not thicken too much in cold start-up temperatures and does not thin out too much as the engine heats up.
• Multi-grade oil is the solution to this problem, designed to maintain a relatively stable viscosity across a range of temperatures.

Chapter 2

• An engine oil with lower viscosity at startup (e.g., 40cSt at 104F) is better than an oil with higher viscosity at the same temperature (e.g., 100cSt at 104F) because it will flow better and waste less energy.
• The oil grade (e.g., 5W30) on the store's product is based on SAE J300, which reflects how the viscosity changes with temperature.
• The oil grade XWYY is made up of two parts: the first part (XW) represents cold temperature performance and the second part (YY) represents high temperature performance.
• For cold temperature performance, ratings are 0W, 5W, 10W, 15W, 20W, and 25W, where lower numbers represent better flow at cold temperatures.
• For high temperature performance, ratings are 8, 12, 16, 20, 30, 40, 50, and 60, with higher numbers indicating better viscosity at high temperatures.
• For instance, 5W30 oil has certain cold and high temperature performance characteristics. Oils labeled as 0W30, 5W30, or 10W30 have similar high temperature performance, but different cold temperature performance.
• In our previous 10cSt example, the oil fits into the 30 category of the high temperature performance scale, so it's an XW30 oil.
• Oils such as 0W30 and 10W30 have similar performance at operating temperature, but the 0W30 oil has better performance (lower viscosity) at startup.
• Most engine wear occurs at startup when the oil is too thick. For example, at 75F startup temperature, a 10W30 oil would be thicker than a 0W30 oil.
• Even though both oils reach the desired viscosity at operating temperature, the 0W30 oil doesn't have to change its viscosity as much as the 10W30 oil during startup.
• The difference in startup and operating performance for two oils with different cold temperature grades but same high temperature grade is due to the way the oil is manufactured.

Chapter 3

• Today's engine oil is composed of several components including the base oil mix, viscosity modifying additives, and other additives aimed at preventing wear, cleaning the engine, and extending oil drain intervals.
• Viscosity modifiers or Viscosity Index Improvers (VII) are used to adjust how the final oil blend responds to temperature changes. This enables the creation of different oil grades like 0W30, 5W30, 10W30, etc.
• The right viscosity at operating temperature is achieved by selecting a mix of base oils and a VII to hit the desired grade target. The mix could differ based on several reasons such as better low temperature performance, cost, or other manufacturing considerations.
• Some viscosity modifiers can wear out over time, leading to the thinning of the oil. This wear is usually not significant in normal engines running under everyday conditions.
• There are Pour Point Depressants (PPDs), a class of viscosity modifiers, that prevent the formation of wax crystals as the temperature drops. This helps improve the cold temperature performance of the oil.
• Oil can thin out due to fuel dilution and the wearing out of VIIs, but it can also thicken from oxidation, leading to varnish and sludge formation. Regular oil changes can prevent excessive oxidation.
• Oil volatility can also lead to thickening as lighter fractions of the oil evaporate, leaving behind higher viscosity oils. Oil manufacturers balance the need for lower viscosity oils with the risk of evaporation.
• Viscosity is influenced not just by temperature but also by load and shear forces. Engine oils can thin out under high shear forces, a phenomenon useful at low temperatures but potentially problematic at high temperatures. This is why there's a minimum High-Temperature High Shear (HTHS) requirement for each oil grade.
• Engine manufacturers now recommend lighter oils to improve fuel economy. These oils reach their operational viscosity window faster, consuming less energy.
• Engine oils are being optimized for lower and lower viscosities with engines being designed to run on lower viscosity oils at operating temperature, necessitating more complex oil formulas and better quality base oils. This is where synthetic oils come into play.

Chapter 4

• Synthetic oils are often recommended for high-performance cars due to their benefits over conventional oils. They tend to oxidize slower, extending the oil change interval, and maintain operational viscosity better across temperature changes.
• Synthetic oils don't thicken as much as conventional oils at lower temperatures, offering better cold temperature performance. This can lead to reduced wear and energy waste during start-up.
• Due to their flexibility, synthetic oils can be adjusted to create higher performing products suitable for new engine technologies, including turbochargers that operate at higher speeds and temperatures.
• Synthetic oils perform significantly better in extremely cold temperatures compared to mineral oils. An example is provided where an engine using synthetic Mobil 1 oil turned over at 152 RPM in ice-cold conditions, compared to mineral oils (10W-30 and 10W-40) which turned over at 45 and 32 RPM, respectively.
• Synthetic oils are also more resistant to oxidation and volatility, thereby reducing oil thickening over time. This resistance means synthetic oils can endure longer oil drain intervals and harsher conditions than mineral oils.
• Most synthetic and conventional oils are compatible, meaning one can switch back and forth without issues. The idea that you must stick with synthetics once you start using them is a myth.
• While synthetic oils can offer significant advantages, their use isn't necessary for all drivers. Both synthetic and conventional oils have a variety of users.
• Brand choice doesn't necessarily matter, as there is a lot of competition in the oil manufacturing industry. However, some car manufacturers recommend specific brands as they design and test their engines with those products.
• If choosing an oil, one should check the owner's manual, ensure the correct viscosity grade is selected, consider cold temperature performance, and learn about the different specifications and applications for which oils are designed.

Chapter 5

• Engine oil is a complex blend of components that serve several key functions including enhancing performance, offering protection, and improving fuel economy.
• Engine oils are made thinner to reduce energy consumption and improve fuel economy. This is achieved by bringing the oil closer to its optimal operational viscosity at startup, which requires less energy to heat the oil and make it thinner.
• The viscosity of engine oil can also be modified according to the shear rate of engine components. For instance, in high shear environments, the oil can temporarily thin out to facilitate better flow.
• Additives in engine oil can reduce friction, thus aiding in improving fuel economy.
• Additives also provide wear protection by creating a protective layer on engine parts, preventing metal from wearing away and thus prolonging engine component life.
• Engine oil additives also contribute to engine cleanliness. Additives like detergents and dispersants help clean off deposits from surfaces and keep them trapped in the oil to be removed by the oil filter or during oil change.
• Synthetic oils and anti-oxidants can help combat oil oxidation which can contribute to deposits and varnish, thus keeping engines cleaner for longer.
• Oil makers need to ensure compatibility with various engine materials, considering different parts of the engine may react differently to synthetic oils, mineral oils, and their additives.
• Problems like leaking engine seals that were initially associated with synthetic oils have been solved through a combination of changes in seal materials and the inclusion of ingredients in the oil blend that prevent the issue.
• Learning about engine oil can help in better vehicle maintenance, extending engine life, and improving fuel economy.
• Participating in communities like the Bob is the Oil Guy Forums can help expand knowledge on engine oils and their attributes.

Chapter 6

• The article primarily discusses the process of choosing the right engine oil for your car, highlighting that it's a decision dependent on various factors, including car make and model, driving habits, and climate.
• The factors most people consider while choosing an engine oil are:
  • Brand: Selecting a reputable brand, known for quality.
  • Grade: Choosing the viscosity grade as recommended by the Original Equipment Manufacturer (OEM).
  • Trust: Often people choose brands they trust, or ones recommended by someone they trust.
  • Specifications: Paying attention to key specifications related to the car and oil, such as API (American Petroleum Institute) certification, Dexos1 for GM vehicles, ACEA for European vehicles, and specific certifications for brands like BMW, VW, and MB.
• Other types of oils to consider are:
  • Semi-Synthetic or Synthetic Blend: A mixture of synthetic and conventional base oils.
  • High-Mileage Oils: Specially formulated for vehicles that have been driven a lot.
  • Racing oils: Used for short-term intense operating conditions, but not necessarily suitable for everyday use.
• The oil change interval depends on the OEM recommendation, driving habits, and type of oil used. However, it can be as frequent as every 3000 miles or as infrequent as every 10000 miles.
• DIY vs professional oil change: Either method is acceptable as long as you trust the individual or company doing the change and they use the oil you prefer.
• When asking for advice on forums like BITOG, it's recommended to provide details about your vehicle, driving habits, location, and any specific preferences or problems your car might have.
• For more technical users, they can get their oil evaluated over its lifespan by visiting the Used Oil Analysis forum on BITOG.

Chapter 7

• The "W" in oil like 10W-30 doesn't stand for "winter", it is a designation of one type of testing versus another.
• The oil viscosity is dependent on temperature, with higher grade oils (e.g., 60) having higher viscosity at the same temperature compared to lower grade oils (e.g., 20).
• Over the years, the American Petroleum Institute (API) and the Society of Automotive Engineers (SAE) have improved engine oil performance with ratings from SA to SM (as of 2010).
• Moving from SJ to SL rating brings significant improvements in multiple aspects such as maximum cam plus lifter wear, sludge buildup, varnish rating, high temperature deposits, and high temperature volatility.
• The pumping viscosity of the oil is crucial for engine operation at low temperatures. Some oils, particularly SAE 10W-30 and 10W-40, have experienced failures in field due to oil forming gel structures at low temperatures.
• Tests designed for oils are made to mimic real-life conditions.
• The author recommends using highest rated motor oil available, regardless of the vehicle age or condition. Even for older engines requiring a thicker grade, it should be SL or SM rated.
• SH, SJ, and SL ratings were introduced in 1993, 1997, and 2001 respectively. According to ASTM D 4485, SL rated oils are superior and can be used in all vehicles requiring SJ and all earlier categories.
• There's a concern about SM oils having less Zinc DialkylDithioPhosphate (ZDDP) than SL and older oils. However, the usage of ZDDP was due to its low cost and multiple functions rather than superior performance. Some newer oils do not contain ZDDP and still perform excellently.
• Too much ZDDP can actually be corrosive and increase wear. A level of 0.03 is sufficient for proper function.
• The author provided links to the American Society for Testing and Materials, Society of Automotive Engineers, and the American Petroleum Institute for further information.

If you haven't read the articles yourself, you're more than welcome to read my notes above. I thought that the topics I brought up in this thread might merit some consideration.

Thank you.

Do you understand what you posted?

 

[TiGeo]

Hello fellow BITOG members!

I'm Chris, and I've been around cars for most of my life. However, I have a few questions on certain aspects of engine oils that I'd love your input on. It's always great to get a range of perspectives from the wealth of knowledge on this forum.

• Conventional vs. Synthetic Oil: I understand that there's been a considerable shift from conventional to synthetic oils over the past couple of decades. The science of it still eludes me though, so I'm hoping someone could clarify what the actual benefits and upsides are for each type.
  
  From what I've read, conventional oil comes from refined crude oil and is suitable for normal, everyday driving conditions. It's cheaper and gets the job done. On the other hand, synthetic oil, created through a synthetic process, seems to be resistant to high temperatures, provides better engine protection and performance, and flows better in cold temperatures. It's more expensive, though. I'm wondering if there are more specific benefits or drawbacks to each that I should consider?

You can buy fully synthetic motor oil for so cheap I fail to see how anyone could justify the few dollars saved going with conventional at this point in any modern vehicle. There are no drawbacks to modern synthetic oils from any of the major brands you can buy at the auto parts store or Walmart. Of course the "syn blends" are a few bucks less and you'll never show me that doing the same intervals etc. won't provide the same results. Case in point; my 2013 Focus bought new has 125K/10 years of the first 100K of that is all 5W20 Motorcraft syn blend changed at 5-7.5K intervals. I coudl certainly continue using a conventional/syn blend but as I said above, for $2-3 more I'll just use "fully synthetic" b/c...it makes me feel good if for no other reason.

• High Mileage Motor Oils and Seal Conditioners: Now, this is something I've always wondered about. How exactly are high mileage motor oils made differently compared to their regular counterparts, and what are these "seal conditioners" they often mention?
  
  My guess is that high mileage oils have additives that help preserve and protect the engine components, but I'd love to know more. Are there significant benefits to switching to high mileage oil once your vehicle crosses a certain mileage?

I don't believe there is anything defininitive you will find saying one way or the other w/r to using a HM oil vs. not and the topic has been debated here many times - search/read but you'll land in the same place. I've run a HM oil in my older cars for no other reason than it was what was availble in Supertech at Walmart when I went to buy supplies for oil changes.

• Oil Change Interval: Lastly, I'm curious about the ideal oil change interval. I know that the common recommendation is every 3,000 to 5,000 miles for conventional oil and 7,500 to 10,000 miles for synthetic. But what if our primary concern is maximum wear protection and engine longevity? Would the interval be different in this case?

Thanks so much in advance for any insights you can share on these topics. I'm looking forward to learning from all of you!

Chris

As above, nothing definitively will show that 3K, 5K, 7.5K, 10K have any positive/negatives beyond what is theoretical or assumed. For every "I changed my oil every 3K and my truck went a bazillion miles" there is another example of the same with a longer interval. 5K seems to be the new 3K in 2023 with 7.5-10K for those driving longer distances/highway being common. GDI and fuel dilution are the primary drivers of shortening OCIs. Spend some time in the UOA sub-forum and you'll get an idea. I ran a 2000 Jetta (NA 2.0/PI) to 225K/14 years with the majority of that at 10K changes with M1 0W40 b/c it was a highway warrior at 30K per year at times. Buying some of the more popular "super" oils that are discussed here ad-nauseum could warrant going 10K+ easily for most folks but I bet the math won't show that you save money over shorter intervals with MUCH cheaper oils.

TLDR: any common name brand syn oil at 5-10K miles with a new filter is basically the way to go for most folks. This is simply my opinion of course. Most of BITOG is debating the nuances of this stuff. Since you thanked me in advance of me deciding to respond...you're welcome.

 

[marc1]

You can buy fully synthetic motor oil for so cheap I fail to see how anyone could justify the few dollars saved going with conventional at this point in any modern vehicle.

This is exactly my take as well. The delta is about $1.20 / L ($.88 usd / 1.05 us.qt.) where I live (both on sale so apples to apples comparison) therefore I buy synthetic for everything now, old muscle and, of course, newer cars in my fleet - which actually require it. The gap seemed to close about 10 years ago. There is no conventional left in my stash, so even my pressure washer will get synthetic now. The only time I would use conventional now would be a new engine break in on one of my old muscle cars.

 

[dnewton3]

The "ideal oil change interval" is not a one-size-fits-all value. You want a specific number, you have to give very detailed and specific parameters for consideration:
- what make, model, year of vehicle
- what operational conditions exist
- what environmental conditions are prevalent? Seasonal concerns?
- what is the threshold for lube costs?
- what commitment can/will be made to UOAs, PCs, etc?

I recommend you spend a lot more time reading and a lot less copy/paste time. You seem to be able to regurgitate the info, but I'm not convinced you understand it, or you'd already realize there's no perfect OCI, any more than there's a perfect oil, or filter, or tires, or toothpaste ... For any situation, there's a group of products that will give a desirable result for the cost one is willing to incur. But that's only applicable to that one situation and as soon as parameters change, the answer changes.

Your notes discuss SH and SL and SM lubes; sir - we're WAY past those API designations. You need to read more current info.

 

[wpod]

What you have read is mostly inconsequential. All oils have seal conditioners. Lots of syn oils are highly refined petroleum oil and oils have a blend of base stocks. Some where around the manufactures recommended oils is a good place to be and too long oil change intervals are in general not the best idea. Just to keep it simple.

 

[Nesterenko]

any common name brand syn oil at 5-10K miles with a new filter is basically the way to go for most folks

In a nutshell this is OCI 101.

 

[53' Stude]

I did, even took notes:

Chapter 1

• Viscosity is a fluid's resistance to flow. High viscosity fluids don't flow easily, and low viscosity fluids flow easily.
• Engine oils used to be simple refined fluids, with different oils having different flow rates, denoted by letters A, B, C. The Society of Automotive Engineers (SAE) later introduced a numerical system.
• Modern engine oils have various additives to modify their behavior with changing temperatures, complicating the grading system.
• Most people think that oil thins out when it gets hot and that is the issue. But, the real problem is oil thickening when it cools.
• 90% of engine wear is said to occur at startup, which is mostly due to oil's increased viscosity (thickness) at lower temperatures.
• Oil thickness increases as the temperature decreases. For instance, oil with a viscosity of 10cSt at 212F could become 100cSt at 104F, and 250cSt at 32F.
• In very cold conditions, oil can thicken so much that it cannot lubricate the engine properly, leading to increased wear and possible engine failure.
• A simple solution might be to maintain oil at a constant viscosity (e.g., 10cSt) but that won't work because as the engine gets hotter, such oil would be too thin.
• We need an oil with the right operating temperature viscosity that does not thicken too much in cold start-up temperatures and does not thin out too much as the engine heats up.
• Multi-grade oil is the solution to this problem, designed to maintain a relatively stable viscosity across a range of temperatures.

Chapter 2

• An engine oil with lower viscosity at startup (e.g., 40cSt at 104F) is better than an oil with higher viscosity at the same temperature (e.g., 100cSt at 104F) because it will flow better and waste less energy.
• The oil grade (e.g., 5W30) on the store's product is based on SAE J300, which reflects how the viscosity changes with temperature.
• The oil grade XWYY is made up of two parts: the first part (XW) represents cold temperature performance and the second part (YY) represents high temperature performance.
• For cold temperature performance, ratings are 0W, 5W, 10W, 15W, 20W, and 25W, where lower numbers represent better flow at cold temperatures.
• For high temperature performance, ratings are 8, 12, 16, 20, 30, 40, 50, and 60, with higher numbers indicating better viscosity at high temperatures.
• For instance, 5W30 oil has certain cold and high temperature performance characteristics. Oils labeled as 0W30, 5W30, or 10W30 have similar high temperature performance, but different cold temperature performance.
• In our previous 10cSt example, the oil fits into the 30 category of the high temperature performance scale, so it's an XW30 oil.
• Oils such as 0W30 and 10W30 have similar performance at operating temperature, but the 0W30 oil has better performance (lower viscosity) at startup.
• Most engine wear occurs at startup when the oil is too thick. For example, at 75F startup temperature, a 10W30 oil would be thicker than a 0W30 oil.
• Even though both oils reach the desired viscosity at operating temperature, the 0W30 oil doesn't have to change its viscosity as much as the 10W30 oil during startup.
• The difference in startup and operating performance for two oils with different cold temperature grades but same high temperature grade is due to the way the oil is manufactured.

Chapter 3

• Today's engine oil is composed of several components including the base oil mix, viscosity modifying additives, and other additives aimed at preventing wear, cleaning the engine, and extending oil drain intervals.
• Viscosity modifiers or Viscosity Index Improvers (VII) are used to adjust how the final oil blend responds to temperature changes. This enables the creation of different oil grades like 0W30, 5W30, 10W30, etc.
• The right viscosity at operating temperature is achieved by selecting a mix of base oils and a VII to hit the desired grade target. The mix could differ based on several reasons such as better low temperature performance, cost, or other manufacturing considerations.
• Some viscosity modifiers can wear out over time, leading to the thinning of the oil. This wear is usually not significant in normal engines running under everyday conditions.
• There are Pour Point Depressants (PPDs), a class of viscosity modifiers, that prevent the formation of wax crystals as the temperature drops. This helps improve the cold temperature performance of the oil.
• Oil can thin out due to fuel dilution and the wearing out of VIIs, but it can also thicken from oxidation, leading to varnish and sludge formation. Regular oil changes can prevent excessive oxidation.
• Oil volatility can also lead to thickening as lighter fractions of the oil evaporate, leaving behind higher viscosity oils. Oil manufacturers balance the need for lower viscosity oils with the risk of evaporation.
• Viscosity is influenced not just by temperature but also by load and shear forces. Engine oils can thin out under high shear forces, a phenomenon useful at low temperatures but potentially problematic at high temperatures. This is why there's a minimum High-Temperature High Shear (HTHS) requirement for each oil grade.
• Engine manufacturers now recommend lighter oils to improve fuel economy. These oils reach their operational viscosity window faster, consuming less energy.
• Engine oils are being optimized for lower and lower viscosities with engines being designed to run on lower viscosity oils at operating temperature, necessitating more complex oil formulas and better quality base oils. This is where synthetic oils come into play.

Chapter 4

• Synthetic oils are often recommended for high-performance cars due to their benefits over conventional oils. They tend to oxidize slower, extending the oil change interval, and maintain operational viscosity better across temperature changes.
• Synthetic oils don't thicken as much as conventional oils at lower temperatures, offering better cold temperature performance. This can lead to reduced wear and energy waste during start-up.
• Due to their flexibility, synthetic oils can be adjusted to create higher performing products suitable for new engine technologies, including turbochargers that operate at higher speeds and temperatures.
• Synthetic oils perform significantly better in extremely cold temperatures compared to mineral oils. An example is provided where an engine using synthetic Mobil 1 oil turned over at 152 RPM in ice-cold conditions, compared to mineral oils (10W-30 and 10W-40) which turned over at 45 and 32 RPM, respectively.
• Synthetic oils are also more resistant to oxidation and volatility, thereby reducing oil thickening over time. This resistance means synthetic oils can endure longer oil drain intervals and harsher conditions than mineral oils.
• Most synthetic and conventional oils are compatible, meaning one can switch back and forth without issues. The idea that you must stick with synthetics once you start using them is a myth.
• While synthetic oils can offer significant advantages, their use isn't necessary for all drivers. Both synthetic and conventional oils have a variety of users.
• Brand choice doesn't necessarily matter, as there is a lot of competition in the oil manufacturing industry. However, some car manufacturers recommend specific brands as they design and test their engines with those products.
• If choosing an oil, one should check the owner's manual, ensure the correct viscosity grade is selected, consider cold temperature performance, and learn about the different specifications and applications for which oils are designed.

Chapter 5

• Engine oil is a complex blend of components that serve several key functions including enhancing performance, offering protection, and improving fuel economy.
• Engine oils are made thinner to reduce energy consumption and improve fuel economy. This is achieved by bringing the oil closer to its optimal operational viscosity at startup, which requires less energy to heat the oil and make it thinner.
• The viscosity of engine oil can also be modified according to the shear rate of engine components. For instance, in high shear environments, the oil can temporarily thin out to facilitate better flow.
• Additives in engine oil can reduce friction, thus aiding in improving fuel economy.
• Additives also provide wear protection by creating a protective layer on engine parts, preventing metal from wearing away and thus prolonging engine component life.
• Engine oil additives also contribute to engine cleanliness. Additives like detergents and dispersants help clean off deposits from surfaces and keep them trapped in the oil to be removed by the oil filter or during oil change.
• Synthetic oils and anti-oxidants can help combat oil oxidation which can contribute to deposits and varnish, thus keeping engines cleaner for longer.
• Oil makers need to ensure compatibility with various engine materials, considering different parts of the engine may react differently to synthetic oils, mineral oils, and their additives.
• Problems like leaking engine seals that were initially associated with synthetic oils have been solved through a combination of changes in seal materials and the inclusion of ingredients in the oil blend that prevent the issue.
• Learning about engine oil can help in better vehicle maintenance, extending engine life, and improving fuel economy.
• Participating in communities like the Bob is the Oil Guy Forums can help expand knowledge on engine oils and their attributes.

Chapter 6

• The article primarily discusses the process of choosing the right engine oil for your car, highlighting that it's a decision dependent on various factors, including car make and model, driving habits, and climate.
• The factors most people consider while choosing an engine oil are:
  • Brand: Selecting a reputable brand, known for quality.
  • Grade: Choosing the viscosity grade as recommended by the Original Equipment Manufacturer (OEM).
  • Trust: Often people choose brands they trust, or ones recommended by someone they trust.
  • Specifications: Paying attention to key specifications related to the car and oil, such as API (American Petroleum Institute) certification, Dexos1 for GM vehicles, ACEA for European vehicles, and specific certifications for brands like BMW, VW, and MB.
• Other types of oils to consider are:
  • Semi-Synthetic or Synthetic Blend: A mixture of synthetic and conventional base oils.
  • High-Mileage Oils: Specially formulated for vehicles that have been driven a lot.
  • Racing oils: Used for short-term intense operating conditions, but not necessarily suitable for everyday use.
• The oil change interval depends on the OEM recommendation, driving habits, and type of oil used. However, it can be as frequent as every 3000 miles or as infrequent as every 10000 miles.
• DIY vs professional oil change: Either method is acceptable as long as you trust the individual or company doing the change and they use the oil you prefer.
• When asking for advice on forums like BITOG, it's recommended to provide details about your vehicle, driving habits, location, and any specific preferences or problems your car might have.
• For more technical users, they can get their oil evaluated over its lifespan by visiting the Used Oil Analysis forum on BITOG.

Chapter 7

• The "W" in oil like 10W-30 doesn't stand for "winter", it is a designation of one type of testing versus another.
• The oil viscosity is dependent on temperature, with higher grade oils (e.g., 60) having higher viscosity at the same temperature compared to lower grade oils (e.g., 20).
• Over the years, the American Petroleum Institute (API) and the Society of Automotive Engineers (SAE) have improved engine oil performance with ratings from SA to SM (as of 2010).
• Moving from SJ to SL rating brings significant improvements in multiple aspects such as maximum cam plus lifter wear, sludge buildup, varnish rating, high temperature deposits, and high temperature volatility.
• The pumping viscosity of the oil is crucial for engine operation at low temperatures. Some oils, particularly SAE 10W-30 and 10W-40, have experienced failures in field due to oil forming gel structures at low temperatures.
• Tests designed for oils are made to mimic real-life conditions.
• The author recommends using highest rated motor oil available, regardless of the vehicle age or condition. Even for older engines requiring a thicker grade, it should be SL or SM rated.
• SH, SJ, and SL ratings were introduced in 1993, 1997, and 2001 respectively. According to ASTM D 4485, SL rated oils are superior and can be used in all vehicles requiring SJ and all earlier categories.
• There's a concern about SM oils having less Zinc DialkylDithioPhosphate (ZDDP) than SL and older oils. However, the usage of ZDDP was due to its low cost and multiple functions rather than superior performance. Some newer oils do not contain ZDDP and still perform excellently.
• Too much ZDDP can actually be corrosive and increase wear. A level of 0.03 is sufficient for proper function.
• The author provided links to the American Society for Testing and Materials, Society of Automotive Engineers, and the American Petroleum Institute for further information.

If you haven't read the articles yourself, you're more than welcome to read my notes above. I thought that the topics I brought up in this thread might merit some consideration.

Thank you.

 

[M56959]

Mercy lock.

Asking multiple questions about topics that have been answered several hundred times helps no one.