severe driving conditions questions
- Thread starter mozart
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yes, frequent stop-n-go driving and short trips, dusty conditions, heavy load, etc. all constitutes to what we referred to as "severe conditions".
Oil should be changed a bit more frequently than what constitutes as "normal driving".
Don't forget that with advancements in motor oils during the past 20 yrs or so and with auto manufacturers, API, ILSAC, SAE, etc. plays a role in ensuring oil meets all the industry's standards RE: cleanliness, long service life, wear , etc., it's no longer Gp 1 (even conventional motor oils are now a blend of at least Gp2+, which the base oil itself is way more robust than what it used to be back in Gp 1 days of yore).
In other words: unless you have deep pockets or you run a machine that specified full syn, otherwise, most semi-syn or brand name conventional motor oil sold in NA are good enough for stock mass-produced vehicles.
My 2c's worth.
Q.
Oil should be changed a bit more frequently than what constitutes as "normal driving".
Don't forget that with advancements in motor oils during the past 20 yrs or so and with auto manufacturers, API, ILSAC, SAE, etc. plays a role in ensuring oil meets all the industry's standards RE: cleanliness, long service life, wear , etc., it's no longer Gp 1 (even conventional motor oils are now a blend of at least Gp2+, which the base oil itself is way more robust than what it used to be back in Gp 1 days of yore).
In other words: unless you have deep pockets or you run a machine that specified full syn, otherwise, most semi-syn or brand name conventional motor oil sold in NA are good enough for stock mass-produced vehicles.
My 2c's worth.
Q.
As I understand:
1. Oil pressure is low. This means there is a minimal film on certain critical moving parts.
2. Coolant is circulating slowly. This means the cooling system is not as effective.
3. Combustion is not very efficient. This means there is more contamination generated that might end up in the oil.
4. Since the engine doesn't spend as much time at operating temps, any contamination (e.g. fuel, by-products, water condensation) that does get into the oil doesn't have a chance to "cook off."
This is all because average RPMs are low and a lot of time is spent at or near idle.
Synthetics usually hold films better, survive heat better, and deal with contamination better (i.e. without breaking down or losing performance in any of those conditions). On the other hand, a modern conventional should work just fine in a modern engine, provided it is up to the required spec and is changed at the right intervals.
1. Oil pressure is low. This means there is a minimal film on certain critical moving parts.
2. Coolant is circulating slowly. This means the cooling system is not as effective.
3. Combustion is not very efficient. This means there is more contamination generated that might end up in the oil.
4. Since the engine doesn't spend as much time at operating temps, any contamination (e.g. fuel, by-products, water condensation) that does get into the oil doesn't have a chance to "cook off."
This is all because average RPMs are low and a lot of time is spent at or near idle.
Synthetics usually hold films better, survive heat better, and deal with contamination better (i.e. without breaking down or losing performance in any of those conditions). On the other hand, a modern conventional should work just fine in a modern engine, provided it is up to the required spec and is changed at the right intervals.
Pretty much all oil and auto manufacturers say this because, yes, it's true. Specifically, lots of idling. Also, short trips, where the oil never gets up to temperature, or for long enough.
I imagine if you took a random survey of the general public you'd find flip-flopped results. Those who drive on the highway a lot thinking that they were driving their engines hard and might fall into the "severe service" category, which those who only drive a couple of miles a day to work and back think they are being really easy on the oil.
Next time you're shopping for a used car and hear about the little old lady only driving it to church on Sunday, put on a suspicious face, take on an accusatory tone, and start grilling the salesman about just what steps the old gal took to compensate for the severe service she subjected the engine to. ;-)
I imagine if you took a random survey of the general public you'd find flip-flopped results. Those who drive on the highway a lot thinking that they were driving their engines hard and might fall into the "severe service" category, which those who only drive a couple of miles a day to work and back think they are being really easy on the oil.
Next time you're shopping for a used car and hear about the little old lady only driving it to church on Sunday, put on a suspicious face, take on an accusatory tone, and start grilling the salesman about just what steps the old gal took to compensate for the severe service she subjected the engine to. ;-)
Most people may over estimate their driving condition. Since you are interested , the best way to find out how the oil holds up is to do an oil analysis for your type of operation. You do not need to do oil analysis all the time. You are implying that syn oil is prefered. Unless syn is recommended by the manufacture ,or you run your engine hard enough to heat the oil up to where syn oils would benefit which is unlikley. or you live where it gets below 0*f ,or extend your oil change intervals but then a HDEO could be used for that , Syn oils may not be of any benefit.
Originally Posted By: d00df00d
As I understand:
1. Oil pressure is low. This means there is a minimal film on certain critical moving parts.
2. Coolant is circulating slowly. This means the cooling system is not as effective.
3. Combustion is not very efficient. This means there is more contamination generated that might end up in the oil.
4. Since the engine doesn't spend as much time at operating temps, any contamination (e.g. fuel, by-products, water condensation) that does get into the oil doesn't have a chance to "cook off."
This is all because average RPMs are low and a lot of time is spent at or near idle.
Synthetics usually hold films better, survive heat better, and deal with contamination better (i.e. without breaking down or losing performance in any of those conditions). On the other hand, a modern conventional should work just fine in a modern engine, provided it is up to the required spec and is changed at the right intervals.
But then Taxicab engines last a long time running bulk oils in the exact type of operation you posted.
As I understand:
1. Oil pressure is low. This means there is a minimal film on certain critical moving parts.
2. Coolant is circulating slowly. This means the cooling system is not as effective.
3. Combustion is not very efficient. This means there is more contamination generated that might end up in the oil.
4. Since the engine doesn't spend as much time at operating temps, any contamination (e.g. fuel, by-products, water condensation) that does get into the oil doesn't have a chance to "cook off."
This is all because average RPMs are low and a lot of time is spent at or near idle.
Synthetics usually hold films better, survive heat better, and deal with contamination better (i.e. without breaking down or losing performance in any of those conditions). On the other hand, a modern conventional should work just fine in a modern engine, provided it is up to the required spec and is changed at the right intervals.
But then Taxicab engines last a long time running bulk oils in the exact type of operation you posted.
Originally Posted By: d00df00d
...and?
exactly.
...and?
exactly.
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Some are equating stop and go with short trip. Stop and go is urban driving where you spend a lot of fuel and don't accumulate anything on the odometer.
That's basically the reason stop and go is defined as severe. It's otherwise very easy on oil. It's typically spending the vast majority of the mileage (as little as that may be) at temperature.
If you're spending 20 minutes operating, you're (most likely) reaching the same oil temps under most conditions. On the highway you'll travel more miles.
That's basically the reason stop and go is defined as severe. It's otherwise very easy on oil. It's typically spending the vast majority of the mileage (as little as that may be) at temperature.
If you're spending 20 minutes operating, you're (most likely) reaching the same oil temps under most conditions. On the highway you'll travel more miles.
Originally Posted By: d00df00d
As I understand:
1. Oil pressure is low. This means there is a minimal film on certain critical moving parts.
2. Coolant is circulating slowly. This means the cooling system is not as effective.
3. Combustion is not very efficient. This means there is more contamination generated that might end up in the oil.
4. Since the engine doesn't spend as much time at operating temps, any contamination (e.g. fuel, by-products, water condensation) that does get into the oil doesn't have a chance to "cook off."
This is all because average RPMs are low and a lot of time is spent at or near idle.
Synthetics usually hold films better, survive heat better, and deal with contamination better (i.e. without breaking down or losing performance in any of those conditions). On the other hand, a modern conventional should work just fine in a modern engine, provided it is up to the required spec and is changed at the right intervals.
1. Why would you want a high oil pressure when the engine is at idle? There is nho load.
2. Same as above, at idle the engine produces the least amount of heat.
3. That was true with carburators, but with fuel injection and computer control, once the engine goes into the closed loop operation, there is always the right amount of fuel delivered to keep the combustion optimal.
4. All stop and go driving doesn't automatically equal short trips. Since I move my commute is 100% city, but it still takes about 30 minutes, how is it different from 30 mins of highway driving?
In general, I think very short trips are worst coupled with cold climate. If your commute is about 30 or more minutes, it doesn't really matter if it is city or highway, unless you redline the car every stop light
As I understand:
1. Oil pressure is low. This means there is a minimal film on certain critical moving parts.
2. Coolant is circulating slowly. This means the cooling system is not as effective.
3. Combustion is not very efficient. This means there is more contamination generated that might end up in the oil.
4. Since the engine doesn't spend as much time at operating temps, any contamination (e.g. fuel, by-products, water condensation) that does get into the oil doesn't have a chance to "cook off."
This is all because average RPMs are low and a lot of time is spent at or near idle.
Synthetics usually hold films better, survive heat better, and deal with contamination better (i.e. without breaking down or losing performance in any of those conditions). On the other hand, a modern conventional should work just fine in a modern engine, provided it is up to the required spec and is changed at the right intervals.
1. Why would you want a high oil pressure when the engine is at idle? There is nho load.
2. Same as above, at idle the engine produces the least amount of heat.
3. That was true with carburators, but with fuel injection and computer control, once the engine goes into the closed loop operation, there is always the right amount of fuel delivered to keep the combustion optimal.
4. All stop and go driving doesn't automatically equal short trips. Since I move my commute is 100% city, but it still takes about 30 minutes, how is it different from 30 mins of highway driving?
In general, I think very short trips are worst coupled with cold climate. If your commute is about 30 or more minutes, it doesn't really matter if it is city or highway, unless you redline the car every stop light
the taxi cab owner/operators I've had to deal with use the cheapest parts they can find, and I'm sure they buy the cheapest oil they can find as well. when AZ sold the valucraft oil for pre 1990 cars, the SF rated oil, the taxi companies kept buying it for their 2002+ Crown Vics and Dodge Caravan's. and of course..the valucraft oil filter(fram C filter in disguise).
THEN... they wanted a discount. I hate dealing with taxi cabs.
And you want to know why your car doesn't last as long as it should..
whatever you put in, you get out.
THEN... they wanted a discount. I hate dealing with taxi cabs.
And you want to know why your car doesn't last as long as it should..
whatever you put in, you get out.
I always follows the "severe" service + 1k (3k for severe, + 1k, making my OCIs around 4k) - since the way I looked at it, sure I did/do make some early-morning trips, at which time there is still moisture in the air, and dew on the ground, though the oil may not make it to it's "normal" temperature, on my way to work, the 9 mile highway drive, at 70-75 mph would "compensate" for my 2-3 stop-and-go or "city driving" - consisting of 4-8 miles in the early morning.
Surely on the way to work, any moisture and unburned gas would get burned off. That's my theory anyways.
Though I never did get a UOA done on the oil....since it got totaled/T-boned by a 83 year old lady.
@KrisZ: you're #4 point, the only thing I could think of, your 30 mins highway vs. 30 minute city drive, only thing I could think of would be fuel dilution, say getting into the oil. Which is why so many people recommend UOAs, not often, but every now and again.
Though my take on things, if you haven't been "sold" on a particular oil brand, weight, etc....no point in doing a UOA until you find one you really like, and can devote to it, easier to compare apples to apples, than apples to oranges
Say, a UOA of PYB 5-30 vs. Castol GTX 5-30 if you were to go switching oils later on in the lifetime of the vehicle.
Surely on the way to work, any moisture and unburned gas would get burned off. That's my theory anyways.
Though I never did get a UOA done on the oil....since it got totaled/T-boned by a 83 year old lady.
@KrisZ: you're #4 point, the only thing I could think of, your 30 mins highway vs. 30 minute city drive, only thing I could think of would be fuel dilution, say getting into the oil. Which is why so many people recommend UOAs, not often, but every now and again.
Though my take on things, if you haven't been "sold" on a particular oil brand, weight, etc....no point in doing a UOA until you find one you really like, and can devote to it, easier to compare apples to apples, than apples to oranges
Say, a UOA of PYB 5-30 vs. Castol GTX 5-30 if you were to go switching oils later on in the lifetime of the vehicle.- Status
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