Engine issues caused by thin oils?

[shDK]

Hi all.

All over the internet, partly also on this forum. People are having a hard time accepting thiner and thinner oil. I have read a lot of arguments for and against thin oils.

But..are there actually any cases where engines have reliability problems. Where it is proven it is because of thin oils. Let's say 0w-16. And I mean where it can be proven that the manufacturer actually spec too thin oils.

Have a nice day.
kindly
Søren

 

[demarpaint]

 

[kschachn]

Honestly about 500 discussions on here about thick vs. thin. Has to be nearly the #1 topic. Surely in 10 years you’ve seen them?

No manufacturer is “spec too thin” of an oil. That’s not the point at all. One gets “acceptable” wear under most conditions using the recommended grade. Again that’s not the point.

 

[PimTac]

 

[fantastic]

Manufacturers spec a grade for their engines that have undergone extensive testing. Oils that are specd have been done successfully for many moons.

However, we have started seeing many folks step up a grade to combat fuel delusion in the newer direct injection type engines to help the oil "stay in grade" as in within oems recommended viscosity.

 

[Zee09]

Oil be thick and oil be thin.
How do it know?

 

[dfarr67]

At the end of the day I think it all depends on the owners maintenance regimen, and some engines although might be good but maintenance sensitive while others may tolerate abuse.

 

[BMWTurboDzl]

Hi all.

All over the internet, partly also on this forum. People are having a hard time accepting thiner and thinner oil. I have read a lot of arguments for and against thin oils.

But..are there actually any cases where engines have reliability problems. Where it is proven it is because of thin oils. Let's say 0w-16. And I mean where it can be proven that the manufacturer actually spec too thin oils.

Have a nice day.
kindly
Søren

Humans are naturally skeptical.
They will equate "sporty driving" as an equivalent to track conditions in order to justify heavier weight.
They assume automakers are looking to cause the premature failure of their engine so that the consumer will have to buy a new one.
They use heavier viscosities in other areas of the world as proof that the automaker just wants them to buy a new car.
The reality is that engine failures caused using the recommended viscosity are few and far between.

 

[loneryder]

Don't think the 0-16 and 0-8 oils have been in use long enough to see engine problems. Anybody seen a Toyota with well over 100k using 0-16 oils? Why do they still go with 20 wt oil in their V6's?

 

[Pablo]

No.

 

[Cujet]

The definitive answer is that “it depends”. It really is that simple.

it is worth noting that the better manufacturers and/or makers of highly stressed engines have taken steps to keep cam chains alive by micro coating the pins, and rod bearings alive by increasing diameter and offsetting the rod bolts to fit the larger parts down the bore.

One manufacturer I love builds a 200MPH machine and took all these steps with good results on 0W-20. With the exception of the main bearings, which remained unchanged from the base engine. Guess what held up and what didn’t ?

 

[Bill7]

Hi all.

All over the internet, partly also on this forum. People are having a hard time accepting thiner and thinner oil. I have read a lot of arguments for and against thin oils.

But..are there actually any cases where engines have reliability problems. Where it is proven it is because of thin oils. Let's say 0w-16. And I mean where it can be proven that the manufacturer actually spec too thin oils.

Have a nice day.
kindly
Søren

I've decided to only use 5W-30 full synthetic oil with short OCI's
in any vehicle I have now or any vehicle I will ever buy in the future.
It's a great feeling of independence knowing all this thin oil / 10k extended oil change interval advice won't ever affect me.

High Temperature / High Sheer does matter. Just google this: HTHS wear graph.

Automakers are trying to avoid CAFE fines and are specing 0W-20, 0W-16, 0W-8 in their owners manuals.
They are also recommending 10k OCI to reduce their advertised cost of ownership, just as long as it's good enough to get them
through the 60k mile warranty period.

I've lost all confidence in owner's manual or maintenance minder recommendations.

 

[Astro14]

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There are many more examples. We’ve had this thick vs. thin debate over and over. Every thread repeats the same positions in the debate.

And in every one of them, someone gets upset, says something inappropriate and then the thread gets locked.

So, honestly, what does this thread hope to accomplish that those threads did not?

We are re-plowing the same, tired, old ground. I just don’t see the point.

 

[Jimmy_Russells]

Don't think the 0-16 and 0-8 oils have been in use long enough to see engine problems. Anybody seen a Toyota with well over 100k using 0-16 oils? Why do they still go with 20 wt oil in their V6's?

There are literally millions in Japan

High Temperature / High Sheer does matter. Just google this: HTHS wear graph.

You post this a lot. The HTHS of 20 grade oil at 100°C is over 4.5

 

[Astro14]

There are literally millions in Japan



You post this a lot. The HTHS of 20 grade oil at 100°C is over 4.5

So, what is the actual oil temperature inside the turbo bearing housing?

Just because the sump, or other measured part, temperature is 100C, doesn’t mean that every part in the engine has oil at that temperature.

Clearly, oil temperature matters, as manufacturers are fitting oil coolers to their small displacement turbo engines.

Then the question becomes: what is the minimum viscosity required for the turbo itself, what temperature does the oil in the turbo reach, and under what conditions?

Only then can we answer the “is the HTHS value sufficient?” question.

 

[Jimmy_Russells]

So, what is the actual oil temperature inside the turbo bearing housing?

Just because the sump, or other measured part, temperature is 100C, doesn’t mean that every part in the engine has oil at that temperature.

Clearly, oil temperature matters, as manufacturers are fitting oil coolers to their small displacement turbo engines.

Then the question becomes: what is the minimum viscosity required for the turbo itself, what temperature does the oil in the turbo reach, and under what conditions?

Only then can we answer the “is the HTHS value sufficient?” question.

Conventional turbos are extremely reliable, they barely ever have bearing issues that aren't due to actual oil feed or drain problems. The bearing is also not subject to compression loading like a road or main bearing. There is more thrust load however, but bearing or shaft wear in turbos traditionally has never been an issue. Just like rod and main bearing wear in an engine is very rarely an issue until you're talking 300k+ miles or so.

 

[Danh]

There are literally millions in Japan



You post this a lot. The HTHS of 20 grade oil at 100°C is over 4.5

I think the current debate is fuel-dilution/TGDI related. Wonder what the HTHS is if 5-7% gasoline is added?

 

[Astro14]

Conventional turbos are extremely reliable, they barely ever have bearing issues that aren't due to actual oil feed or drain problems. The bearing is also not subject to compression loading like a road or main bearing. There is more thrust load however, but bearing or shaft wear in turbos traditionally has never been an issue. Just like rod and main bearing wear in an engine is very rarely an issue until you're talking 300k+ miles or so.

You sidestepped the question.

What viscosity does the turbo require?

What temperature is the oil in that turbo?

Then, and only then, can you defend what you said about the 100C rating being enough.

I am not anti-turbo. I own…let’s see…seven turbo cars. Some of them well over 200,000 miles on the original turbo. I have a good feel for their longevity.

But, and I find this interesting, they all have oil coolers, and they all require a minimum of XW30 oil, with a recommendation of higher if driven under “extreme conditions”.

Turbo bearing clearances haven’t changed.

So, how do you know what viscosity is acceptable, if you don’t know what is required or the operating temperature inside the turbo?

 

[Jimmy_Russells]

You sidestepped the question.

What viscosity does the turbo require?

What temperature is the oil in that turbo?

Then, and only then, can you defend what you said about the 100C rating being enough.

I am not anti-turbo. I own…let’s see…seven turbo cars. Some of them well over 200,000 miles on the original turbo. I have a good feel for their longevity.

But, and I find this interesting, they all have oil coolers, and they all require a minimum of XW30 oil, with a recommendation of higher if driven under “extreme conditions”.

Turbo bearing clearances haven’t changed.

So, how do you know what viscosity is acceptable, if you don’t know what is required or the operating temperature inside the turbo?

Your cars are not a great example since they are mainly European, and older. Mine is only five years old and also recommends C3 30 grade. Collectively the Germans at least didn't start recommending 20 grade oil until about four or five years ago, whether the engine was turbocharged or not. Of course the use case for those cars is a lot different over there than here as well.

I have a lot of experience with rebuilt turbochargers. My place of employment does at least a couple a week. Bearing failure is very rare, they almost always fail because of conditions external to the turbo.

Even if bearing temperature is 150°, or more, it clearly does not pose any problem long term to the life of the turbocharger. I know the viscosity is acceptable because I trust the engineering and I have seen it myself for well over a decade. There is also constant flow of fresh, 90-100° oil. Oil is only actually in the turbocharger for a few seconds, how much can it actually heat up?

End of the day most of the people here are concerned about their wife's daily driver or something, they aren't pulling 10k lbs through the Rockies, when this type of thing may actually matter.

 

[Bill7]

There are literally millions in Japan



You post this a lot. The HTHS of 20 grade oil at 100°C is over 4.5

Japan has a huge tax on older vehicles, so most vehicles in Japan likely get exported after they age a bit, so there may not be too many high mileage cars in Japan for the ultra thin oil effect on engine wear to be analyzed. We know cars that use 30 weight and 20 weight get to 300k miles. But 16 weight, 8 weight, etc, it's an unknown, and there is no benefit to the car owner on having that uncertainty.

The thin versus thick debate used to be between 20 weight and 30 weight oils. The reason there was no answer to that debate was that 20 weight oils still had the HTHS = 2.6 when new, which provided adequate protection on the HTHS wear graph with HTHS = 2.6 being the minimum for adequate protection.

But 16 weight or 8 weight are different oils entirely (breaking the HTHS wear graph's 2.6 minimum for adequate wear protection), and it's an unknown how an engine using 16 weight or 8 weight oil will hold up after 200k or 300k miles.