Thicker oil as engine ages?

[Yuk]

moribundman,

As you know I have a 1.8T. It was sludge in that engine, and absolutely incompetent VW/Audi dealers, that lead me to BITOG. Remember all of those late nights I spent, with your help, trying to decipher VW oil specs? Context is everything...

What I meant is, synthetic isn't relevant to this particular topic. Synthetic can be totally relevant in other questions, such as which oil should be used in a high stress 1.8T environment, but isn't relevant when answering the question,

quote:

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Some people say thicker oil may be used as an engine ages. Is this true?

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[Primus]

Fully agree with TallPaul: the use of a thick oil that is within recommended grades will not increase wear. Europe uses heavier oils and everything is OK. One step up after 150-200.000 km is recommended by number of car engineers. For me it has sense, but the issue is where to find equal quality and same base stock oil. It is not difficult if to start with 0W-30 or 5W-30, but the choice is quite limited in case of 5W-40 oils.

Moribundman,
For your car, like for many Audi/VW, 10W-50 all year round is the best choice. Thus, your initial choice of 5W-50 was very close to the ideal.

 

[moribundman]

Hey Yuk, if I come across as an arse, sorry. The only reason I said what I said regarding synthetic and minerals oils was due to the incorrect statement about the VW/Audi oil chart; a statement which I did not want to let go unaddressed.

As for the thread topic "Some people say thicker oil may be used as an engine ages. Is this true?" what can one really say? "One "may" do anything what one wants. What are you looking for, truth or fact?

When making recommendations, we often make statements based on assumptions and on empirical evidence. And on hearsay. It is extremely easy to argue pro or con the use of thicker oil in an older engine. There's only one way to find out what works best in each old motor.

 

[Yuk]

No harm done.

I hate feeling inarticulate and unable to get my point across. I just want everybody to love me.

 

[huffmuds9320]

The reasons for thicker oil in high mileage engine seems to be more for reducing oil consumption. Higher mileage cars would have oil issues due to aged seals and gaskets. I agree with dr. t, its sort of like a cover up thing. Using a thicker oil will significantly reduce oil consumtion and leaks. But a thicker oil will leave a film of oil in the cylinder walls. Thats why they use that cylinder hone thing to make cross hatch patterns in the wall when they rebuild. Thats all I can say, if the information is not right please correct me.

Sorry I shouldn't have made a bad/wrong statement about the VW/Audi oil chart. Good that mori is making sure the info is interpreted correctly, gotta trust the pros.

 

[moribundman]

Naw, I'm not a pro. I just happen to have looked closely at the manuals the second I noticed discrepancies between the German and English language manuals. Without having seen the German manuals, it isn't exactly clear to what type oil VW oil specs actually refer.

Whether thicker oil reduces consumption may be different from engine to engine. I know at least of one case in which an old Audi engine had more blow-by when using thicker oil, resulting in increased consumption with thicker oil. I believe thicker oil can help with valve stem seal leaks. I also believe that an oil burner may fare better with a thick mineral oil than a thick full synthetic, due to the synthetic's affinity for clinging to the cylinder wall. Mineral oil may get scraped off the cylinder to a higher degree. But as I said, I have nothing else to show than arbitrary beliefs, neither facts not truth.

 

[TallPaul]

quote:

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Originally posted by Eddie:
Make sense to me as thicker oil increases wear so why go heavy too early. ed

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I think this statement needs to be qualified. Within certain limits and depending on the engine and its condition, thicker oil should not significantly increase wear, unless it is excessively thick. For example, maybe jumping from 30 wt to 40 wt is OK, but 50 wt is too much for a given engine. Likewise, too thin an oil could also increase wear.

 

[mikemc]

quote:

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Originally posted by Eddie:
All of the lubracation engineers I talk to recomend the grade recomended by the manufacture UNTILL the engine has worn to the point where oil consumption is a problem. Make sense to me as thicker oil increases wear so why go heavy too early. ed

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Makes sense to me. If it ain't broke, don't fix it.

 

[Yuk]

quote:

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I think this statement needs to be qualified. Within certain limits and depending on the engine and its condition, thicker oil should not significantly increase wear, unless it is excessively thick. For example, maybe jumping from 30 wt to 40 wt is OK, but 50 wt is too much for a given engine. Likewise, too thin an oil could also increase wear.

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Tallpaul is probably right. The quote sounds like pure common sense.... But, if this is true, why is it that almost every Japanese car built before the mid-1990s has maintenance specs that suggest the owner should choose oil based on ambient temperature? Every car I've ever owned, including my 1999 VW Passat, has had a service disclaimer like the one in my Mazda's manual:

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When you change or add oil, select oil with the proper SAE viscosity. Check the accompanying table and select the oil which most closely matches the temperature range you expect to encounter.

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The viscosity range in the manual is from 5W-20 to 20W-50.

I have never seen any warnings, in an owners manual, about oil pumps, or lubrication related parts failing, due to an excessively high viscosity.

 

[Dr. T]

Mori, your observation re: dino vs. synthetic is correct. I too have noticed that in certain engines that consume oil, using synthetic over conventional will increase consumption. I believe some of that is due to the generally 'thinner' and less viscous nature of synthetics as well as increased flow/runniness which increases consumption. It should change though with the cleaning effect of synthetic, albeit over many miles...or use auto-rx.

 

[Ken2]

To oversimplify, bigger bearing clearances require higher viscosity oil. There are many other considerations. If I had a high mileage car where I saw a decrease of oil pressure compared to new, I'd use the thicker oil to get the oil pressure back up to where is was.

I understand, this is just a bandaid. It is still a nearly-wornout engine.


Ken

 

[T-Keith]

Also don't assume your car has larger bearing clearances just because it's old. 100,000 miles on one engine might be much worse then 100,000 miles on another. If your clearances did increase, then you would see a drop in oil pressure. I have never seen a case of that in my high mileage GM cars, all have had 5w30 or 10w30 throughout their life. My 212,000 mile Lesabre has good oil pressure with 5w30 in it right now.

-T

 

[haley10]

quote:

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Originally posted by T-Keith:
Also don't assume your car has larger bearing clearances just because it's old. 100,000 miles on one engine might be much worse then 100,000 miles on another. If your clearances did increase, then you would see a drop in oil pressure. I have never seen a case of that in my high mileage GM cars, all have had 5w30 or 10w30 throughout their life. My 212,000 mile Lesabre has good oil pressure with 5w30 in it right now.

-T

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My experience is that the 3300 or 3800 GM never seem to benefit from any viscosity bump up. Neither do some of the Ford modular V-8's. I have not seen oil consumption rise much in mine with age and mileage.

Increasing viscosity doesn't always reduce consumption. I went from Havoline 10W-40 to PZ 10W-30 in my old 87 Mitsu truck and actually somewhat reduced consumption (minimal). Plus it is more responsive.

You can usually go up one grade without harm, but it may or may not be a benefit, regardless of age.