Will Thinner Oils Damage Your Engine?

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I did find this summary on the February 1987 Consumer Reports article which is not on-line:

Comments on the 1987 Consumer Reports oil test

“... Most oils also passed all the low-temperature tests required in the SAE viscosity grade system, although there were sample-to-sample differences in some products. ...”

“... Four oils -- Kendall Superb 100 10W-40, Kendall GT-1 Turbo 10W-30, Sears Spectrum 5W-30 and Texaco Havoline 5W-30 -- failed low-temperature tests even when more than one sample was evaluated. Consumer Reports' auto engineers suggest you avoid those oils in extremely cold weather. ...”

“... Castrol GTX 10W-40 and 10W-30 and Exxon Uniflo 10W-30 would have been as impressive had all test samples met their viscosity-grade requirements. ...”
Yes but that is what illustrated the problem with using pour point as the indicator of cold-weather performance.

I don't think you understand the discussion here at all.
 
Actually no that was the exact problem, it was black and white. Under certain environmental conditions the oil would gel under shear at the pump pickup tube and could not be pumped.


I mentioned this before but I actually witnessed this. A friend took the oil pan off of his Plymouth Fury and the oil had gelled in the pan. He used a putty knife to remove it. This was Quaker State. This was in the early 80’s.
 
I'm no expert here, but doesn't longevity of things that need each other to define kind of make this a dumb argument?

I mean the spectrum of possibilities includes considering that a terrible engine could still be terrible with any oil, and a great engine could be great with any oil based on how it is designed.

Wouldn't it make more sense to look at the statistics that show which cars have survived the most miles over the years and what engine properties oil properties were recommended to speculate about what the best combination is?
 
I'm no expert here, but doesn't longevity of things that need each other to define kind of make this a dumb argument?

I mean the spectrum of possibilities includes considering that a terrible engine could still be terrible with any oil, and a great engine could be great with any oil based on how it is designed.

Wouldn't it make more sense to look at the statistics that show which cars have survived the most miles over the years and what engine properties oil properties were recommended to speculate about what the best combination is?

https://www.bobistheoilguy.com/forums/
 
I think the answer is, who really knows for sure. How many people keep their vehicle long enough to experience any engine mechanical problems?

Many people on this forum have stated that their particular vehicle has over 300K running a quality 5W-20 with no issues. Is this because of a great engine design that has nothing to do with oil viscosity or that 5W20 protects the engine adequately?

My 14 Mustang GT calls for 5W-20 and is what I currently run in it. Other versions of this car that are more track oriented spec 5W-50. Obviously I could probably run either viscosity or anything in between and be good. If I don't track my car or run it hard, will these higher viscosity oils make the engine last longer? I have not seen any evidence anywhere that it will.
 
The OA does not and can not identify a specific source of any detected wear ...
And no one claimed it did.

What was stated was that it points to potential sources of the abnormal reading.

If the iron is high, it's not likely a bearing.

If it's babbit metals, it's not likely cylinder wear.

Also, the OA is purely dependent of the sample, where, when and how it was taken as to whether it is even relevant.

Terry Dyson, who lived here 2002-09 and did oil analyses for a living would have taken that apart.

Millions of fleet vehicles make it clear that UOAs are relevant.
 
And no one claimed it did. What was stated was that it points to potential sources of the abnormal reading. If the iron is high, it's not likely a bearing. If it's babbit metals, it's not likely cylinder wear. Terry Dyson, who lived here 2002-09 and did oil analyses for a living would have taken that apart. Millions of fleet vehicles make it clear that UOAs are relevant.

No, wrong again

You tried to claim it did (inferring) but got called as a fail ( which it is)

I do them for a profession too and have been for decades so your appeal to an absent authority goes nowhere either.

You have never seen "millions" of anything- I on the other hand have reviewed probably 10 thousand or so over my career and can tell you that at the end of the day the overall use of the data of OA without strict discipline and combined with other data is at best "questionable" in value.

As I said, you have yet to demonstrate and significant level of actual experience on the subject and this is nothing more than obfuscating the issue.
 
No, wrong again

In your opinion.

You tried to claim it did (inferring) but got called as a fail ( which it is)

Also in your opinion, supported by .... your opinion.

You have never seen "millions" of anything-

In your opinion. In the real world of oil testing:

https://www.fleetequipmentmag.com/oil-analysis-testing-explained/

" By evaluating the condition of your lubricant and equipment on a routine basis, minor mechanical problems are discovered before they become serious and expensive to fix. "

https://www.alsglobal.com/en-au/ser...and-coolant-analysis/oil-analysis-and-testing

"Our basic preventative maintenance package is designed to provide early detection of:

Problems in the initial stages of development

Excessive wear and the source of that component’s wear"
 
In your opinion.

Also in your opinion, supported by .... your opinion.

In your opinion....

My opinion: when I join a forum, I introduce myself, establish friends interested in similar topics, and have useful discussion.
You will likely learn something from the positive experience. I know I have learned a lot and made many friends here in 15 years.

Again, that's only my opinion.
 
I recall the problem quite clearly.

The oils in question did NOT meet their pour point specs.

GM noted a large number of engine failures in the northern USA and Canada. They ran their own tests and found that several oils did not meet their pour point specs.

Consumer Reports, a major US testing magazine, ran their own tests and failed - among others - one of the Castrol oils for not meeting its pour point specification.

They also tested for shearing by running the oils through diesel injectors.

The specification change came a decade later.
That's interesting. Two winters ago, I ran a certain Castrol 5W-30 in Wisconsin's -20 degree weather and found it performed terribly. As much as I like the oil in warmer weather, it didn't impress me in the cold.

I switched to QSUD and Rotella GT for wintertime ops, becoming satisfied with their performance.

I also have Kirkland 5W-30 I need to try in the winter. We'll see about that one.
 
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