All You Guys That Think OEM Recommended 16 or 20 Weight...

CumminsMech said:
They’re actually recommending 10w-30 year round in all new 12L coach buses and efficiency series 15L semi engines now. Haven’t seen any oil related issues yet. That being said, most truck fleets still run 15w-40 year round and buses don’t get shut off for long. 5w-40 I think is the sweet spot year round. I’ve used that in all my Cummins, Powerstroke, or 80’s Mercedes diesel engines I’ve had. Ran it in New Mexico/Arizona summers and some Canadian winter trips.
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The 10w-30 you'd put in a diesel is 12cst @100c and has an HTHS of 3.5. I wouldn't consider that a thin oil.
 
ZeeOSix said:
Hard to say. Plenty of engines with just as tight of bearing clearances run with xW-50 oil and have no issues. Look at all the motorcycles that rev to 11,000+ RPM running xW-50 oil. Just because a few S2000s supposedly blew-up because of using 50 doesn't mean 50 is bad for every engine. Could be there is something about the oiling system that doesn't play well with 50 at WOT and high RPM for miles on the autobahn. Was there any oil pressure and temperature data given on these cars running these top speed runs?

I'm curious on what oil filter these cars that smoked the bearings were using? If the oil filter doesn't flow very well at high RPM (and with using heavier oil) then that could have cause the oil pump to hit pressure relief earlier and therefore cut down on the oil flow to the engine enough to cause harm.
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Since the Honda S2000 has a bad reputaion for vibrating the oil filter loose and Honda adressed it with a oil Filter with higher torque specifications, 95% of Honda S2000 owners use the OEM Honda filter. It is a gospel in the S2000 community to only use the dedicated S2000 Filter from Honda. Otherwise you engiene will go Ka-boom in no time. ;) This topic is "Pinned" in Honda S2000 Forums.

There are even dedicated oil filter safety holders or clamps for the S2000 avialable to prevent the oil filter coming loose. https://www.r-parts-store.com/A-S-Performance-Oelfilter-Sicherung/Halter-Honda-S2000

I am using MAHLE or MANN filter torqued down properly with no problems. Funny, the MANN is the hardest to get loose when you change it.
 
Accent Abuser said:
Even regular car manuals that don't specifically recommend higher viscosity state that under extreme conditions a higher viscosity oil may be required.

It just makes no sense how a bearing can fail due to a higher oil viscosity, it just doesn't jive with the physics. As the piston and conrods spin the crankshaft around there is nothing preventing the oil from leaking out of the side of the journal except the small clearances. The faster it rotates the more force is applied to that thin film which can squeeze it out of the bearing. Thin oil is more readily squeezed out of the bearing, thicker oil is not. Then you've got things that rely on the base oil viscosity entirely like the timing chain and cam shaft. I would not be surprised if at 6000+ RPM using 5w-20 if the bearings enter a mixed or even boundary lubrication regime. It's asking for trouble in my opinion.
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There's 2 ways a bearing can fail from excessive oil viscosity.

The first way is heat. Higher viscosity means more hydrodynamic friction and where there's friction, there's heat. This isn't likely in a daily commuter with 220*F sump temps, but a car that's raced or driven "spiritedly" could see accelerated bearing fatigue from prolonged high friction and heat resulting in spalling.

The second way is cavitation. This is rare and difficult to make happen in a car engine, but still a way it can happen. Higher viscosity traps air easier and doesn't like to let go of it making it more susceptible to aeration. On top of that, higher viscosity also means higher oil pressure and higher pressure increases the capacity of entrained air. As it worsens, aeration sharply increases the oil's viscosity, compounding the problem. If it gets aerated enough, that air can release under high pressure in the bearing and cause bearing cavitation.

Higher viscosity will also mean a higher pressure drop across the filter which could mean more bypass events sending dirty oil to the bearings, but this isn't something you'd likely see a noticeable wear pattern from in even 500k miles.

Aside from the bearings, it's common in the Ford small block V8 world to see snapped oil pump drives from using 20W-50 oil and revving it in cool weather. Yes, idiotic user error, but still something that isn't seen with lower viscosity oils.

Some engines with very thin (1mm and 0.7mm) rings with low tension can also have bad effects from high viscosity oils. This is mainly due to the friction mentioned above, but also the oil film thickness. We like the rings to be in full hydrodynamic lubrication through peak piston speed, but too much of a good thing can be a bad thing. It can cause increased oil transport past the rings and upset ring seal.
 
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Correct me if mistaken. But it goes something like this. Thin as possible thick as necessary?

My DD sees 1500rpm for 90% of its life. Therefore it's best to go with the thinnest allowable viscosity as per manufacturer recommendations.
 
RDY4WAR said:
There's 2 ways a bearing can fail from excessive oil viscosity.

The first way is heat. Higher viscosity means more hydrodynamic friction and where there's friction, there's heat. This isn't likely in a daily commuter with 220*F sump temps, but a car that's raced or driven "spiritedly" could see accelerated bearing fatigue from prolonged high friction and heat resulting in spalling.

The second way is cavitation. This is rare and difficult to make happen in a car engine, but still a way it can happen. Higher viscosity traps air easier and doesn't like to let go of it making it more susceptible to aeration. On top of that, higher viscosity also means higher oil pressure and higher pressure increases the capacity of entrained air. As it worsens, aeration sharply increases the oil's viscosity, compounding the problem. If it gets aerated enough, that air can release under high pressure in the bearing and cause bearing cavitation.

Higher viscosity will also mean a higher pressure drop across the filter which could mean more bypass events sending dirty oil to the bearings, but this isn't something you'd likely see a noticeable wear pattern from in even 500k miles.

Aside from the bearings, it's common in the Ford small block V8 world to see snapped oil pump drives from using 20W-50 oil and revving it in cool weather. Yes, idiotic user error, but still something that isn't seen with lower viscosity oils.

Some engines with very thin (1mm and 0.7mm) rings with low tension can also have bad effects from high viscosity oils. This is mainly due to the friction mentioned above, but also the oil film thickness. We like the rings to be in full hydrodynamic lubrication through peak piston speed, but too much of a good thing can be a bad thing. It can cause increased oil transport past the rings and upset ring seal.
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For the first scenario, I'd imagine if one is driving hard enough and in conditions hot enough to achieve those kinds of temperatures, they really need an oil cooler. Reducing viscosity is not going to help. Sure the oil might run somewhat cooler but it's still going to be way too hot and too thin at that point to provide a proper oil film.

Shouldn't oils have proper anti foaming additives? I've never seen a fully formulated modern oil trap and hold air easily or for long even after shaking the devil out of it. Lucas oil stabilizer on the other hand...

Wouldn't the last scenario cause oil consumption? I've never lost a drop of oil over an OCI whether I used 5w-20 or 5w-50.
 
even those 10w-30 are likely still 3.5 cP hths oils, and the engines in trucks, busses and coaches have plenty of cooling capacity. Running at 190F vs 220F gives a lot of headroom in the viscosity department.
 
RDY4WAR said:
There's 2 ways a bearing can fail from excessive oil viscosity.

If it gets aerated enough, that air can release under high pressure in the bearing and cause bearing cavitation.
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Air released under high pressure can also cause pitting of the bearing surface.
 
Jetronic said:
even those 10w-30 are likely still 3.5 cP hths oils, and the engines in trucks, busses and coaches have plenty of cooling capacity. Running at 190F vs 220F gives a lot of headroom in the viscosity department.
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Some 10W-30 oils are, while others aren't. For example Mobil 1 (Vanilla) HM 10W-30 has a 3.5cP HTHS, while Mobil 1 EP HM 10W-30 doesn't. And none of the non-HM Mobil 1 10W-30 oils do. It's pretty interesting how Mobil divided them up, and unless you look up a spec sheet and dig up this information, you, as a customer, won't know.
 
Obi Wan Noobi said:
Some 10W-30 oils are, while others aren't. For example Mobil 1 (Vanilla) HM 10W-30 has a 3.5cP HTHS, while Mobil 1 EP HM 10W-30 doesn't. And none of the non-HM Mobil 1 10W-30 oils do. It's pretty interesting how Mobil divided them up, and unless you look up a spec sheet and dig up this information, you, as a customer, won't know.
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Unless you know that ACEA Sequence A3/B3 requires a minimum 3.5 HT/HS. Again showing how approvals and licenses are useful.
 
kschachn said:
Unless you know that ACEA Sequence A3/B3 requires a minimum 3.5 HT/HS. Again showing how approvals and licenses are useful.
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I agree with your comment, and it's accurate as per Mobil's own website:

Mobil 1 EP HM 10W-30: https://www.mobil.com/en/lubricants...products/mobil-1-extended-performance-10w-30/

Mobil 1 HM 10W-30: https://www.mobil.com/en/lubricants...roducts/products/mobil-1-high-mileage-10w-30/

However, the wast majority of the buying public doesn't know this.
 
Obi Wan Noobi said:
Some 10W-30 oils are, while others aren't. For example Mobil 1 (Vanilla) HM 10W-30 has a 3.5cP HTHS, while Mobil 1 EP HM 10W-30 doesn't. And none of the non-HM Mobil 1 10W-30 oils do. It's pretty interesting how Mobil divided them up, and unless you look up a spec sheet and dig up this information, you, as a customer, won't know.
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It was a response to Cumminsmech, which I forgot to quote. Those are HDEO oils, Mobil 1 is not. Neither are they A3/B4 or C3 oils, btw...
CumminsMech said:
They’re actually recommending 10w-30 year round in all new 12L coach buses and efficiency series 15L semi engines now. Haven’t seen any oil related issues yet. That being said, most truck fleets still run 15w-40 year round and buses don’t get shut off for long. 5w-40 I think is the sweet spot year round. I’ve used that in all my Cummins, Powerstroke, or 80’s Mercedes diesel engines I’ve had. Ran it in New Mexico/Arizona summers and some Canadian winter trips.
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tolian21 said:
Most people that use OEM spec oil drive normally and do not modify their cars.
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This is the majority of people and it is what I am referring to.
tolian21 said:
Did these people have any other modifications or taking their cars to the track? So you find couple posts, and that somehow supposed to make a statistically accurate study? I can go right now to one of those blogs and post a fake issue with OEM speced oil.
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This isn't my concern. I don't do these things and most consumers don't either. How an engine performs with thinner oil after it is modified is not using the vehicle as it is intended. Different ballgame.

Vehicles that are purchased, used as normal, and follow OEM specs, will generally go hundreds of thousands of miles without worry (barring a lemon situation, of course)
 
I worked in car dealer parts departments for 40+ yrs before I retired. I hated this discussion from any of our techs. Even our mechanics would sometimes freak if I made them use a 5w20 instead of a 0w20 in a used car going on the lot. The thicker thinner discussion has gone on for decades. I tried to always under warranty use the spec'd grade then afterwards go with what we saw was best. Many finally came around to my way of thinking and would use what I handed them if we were out of a specific grade or brand. We stocked OE oils and a few other major brands we purchased for the other makes we serviced. I'd look at manufacturers spec and use an alternate approved grade or another oil I knew was an okay substitute for a regular customers 3k-6k interval. Many of our domestic customers wouldn't use the newer intervals so we didn't push it on them. Its their money. I used to laugh at the customers who brought in their own oil and filter that weren't as high a quality as what we sold but paid a tech to changed them. It always cost them about twice in the long run instead of just using what we sold. And whats the reasoning when many of these people have 3-5 yrs leases and aren't keeping the car long term anyway?
While on this subject I'll tell you a few years back when Castrol changed some marketing I bought 5 yrs of oil changes of German 0w40 because of clearance pricing from my wholesaler at $6 a 5qt jug. I've used it in both a 2008 Ford Edge 3.5l and 2008 Audi A3 w/3.2l with no issues of any type. The only difference I see is the Fords oil stays way cleaner longer that it did with any brand of 5w20.
 
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