Another "Taxi" Study: Relationship of Engine Bearing Wear and Oil Rheology 872128

[Bill7]

Timely post from the book o' faces...

View attachment 137423

0W-30 might be the best viscosity for most cars (not 0W-20).

 

[Bill_W]

Wow… The conspiracies. Dated April 2014.

https://apps.dtic.mil/sti/pdfs/ADA624797.pdf

 

[kschachn]

0W-30 might be the best viscosity for most cars (not 0W-20).

A minimum HT/HS is a better indicator than grade.

 

[Bill7]

A minimum HT/HS is a better indicator than grade.

Yes. I prefer to use a thick 5W-30 which has a HTHS of 3.2.
It's better not to use xW-xx grade terminology, as the HTHS varies between low and high allowed HTHS allowed #'s for each grade.
So more accurate to use the HTHS directly.

 

[ZeeOSix]

Yes. I prefer to use a thick 5W-30 which has a HTHS of 3.2.
It's better not to use xW-xx grade terminology, as the HTHS varies between low and high allowed HTHS allowed #'s for each grade.
So more accurate to use the HTHS directly.

SAE J300 only shows a minimum HTHS viscosiy for each grade, not a high and low low like the KV100 spec.

 

[Bill7]

SAE J300 only shows a minimum HTHS viscosiy for each grade, not a high and low low like the KV100 spec.

You're correct on that. Thanks.

 

[4WD]

I upped the HTHS in my 3.6L from 2.6 to 3.5 for additional protection with zero concern about MPG loss which I see as a fantasy quest for the vast majority of vehicles on the road.

Many driving habits lose the MPG savings between xW-20 and xW>20 within 100 miles of an oil change and in my Wrangler, my right foot or a headwind will erase any MPG savings so it is more than pointless to chase it.

Aside from potentially proving how an engine can fail using too thin of a viscosity, I question what else might be proven.

This is another variation of the same circular argument that has happened in countless threads with nothing proven or disproven.

Running low on 0W20 stash and will do the same - use up the 5W30 RGT in the Rubicon …
Think you tested at 5k and called it a day - Mopar did lower it to 5 quarts which is opposite of my 5.3L’s …

 

[CarbonSteel]

Running low on 0W20 stash and will do the same - use up the 5W30 RGT in the Rubicon …
Think you tested at 5k and called it a day - Mopar did lower it to 5 quarts which is opposite of my 5.3L’s …

Yeah, the 2nd Generation 3.6L had a reduction of 1QT from 6.0 to 5.0 (that doesn't stop the dealers from overfilling it though).

With RGT, in 5K, the TBN will be in the 2.x range and (for me) that's good enough.

Given how cheap, I scored the RGT, I see no reason to try and stretch it. Found a deal on FB market place for RGT 0W-20 and grabbed it for my GC.

 

[dihi22]

It would be great if we could have some kind of Oil Monitor on the car that would show when the oil has 2 much fuel or it thins out 2 much.

You have it, its called the dip stick and your nose. If you pull it and smell gasoline anything more than a tiny hint of gas, its too much fuel dilution.

 

[dihi22]

The problem with that scenario and this is just my view on it, is that the main reason engines burn oil is due to the owners not maintaining them regularly. A large chunk of owners let the OCI’s drag out.

Additionally, we don’t need more intrusion from the G.

I'm convinced its also cheap "brown and slippery" bulk barrels of conventional being shot into every car regardless of the quality of oil orded by the customer at these quick loob places. Put any name brand OTS in spec in your car and change on the owners manual recco (yes even the dreaded 10k toyota interval) and i think you will have a much lower chance of developing an oil burner.

I think bad maintenance is just as at fault as owners spinning the dial too long between changes.

 

[ChrisD46]

SAE J300 only shows a minimum HTHS viscosiy for each grade, not a high and low low like the KV100 spec.

So , perhaps better to say : "What minimum HTHS do you believe is appropriate for your specific vehicle and driving style ? I recall seeing an article here (or elsewhere) which used HTHS of 2.6 as a minimum for oil if you drove say a vanilla , non - turbo Corolla gently driven, rarely ever exceeding 4,000 RPM's , not used for towing , driven under little load , in under 95 degree F. temps , etc. . *If you are a more "spirited" driver routinely winding gears out to +4,000 RPM's , under load , drive a turbo , in higher heat , etc. then a minimum HTHS of 3.0 is a better option for you for preventing low wear ?

 

[userfriendly]

So , perhaps better to say : "What minimum HTHS do you believe is appropriate for your specific vehicle and driving style ? I recall seeing an article here (or elsewhere) which used HTHS of 2.6 as a minimum for oil if you drove say a vanilla , non - turbo Corolla gently driven, rarely ever exceeding 4,000 RPM's , not used for towing , driven under little load , in under 95 degree F. temps , etc. . *If you are a more "spirited" driver routinely winding gears out to +4,000 RPM's , under load , drive a turbo , in higher heat , etc. then a minimum HTHS of 3.0 is a better option for you for preventing low wear ?

Some engines are more 'oil pressure dependent' than others.
That's where VMs come into play (VIIs).
With VMs, an oil can have the viscosity it needs at high temperature without an unnecessary boost in power robbing HTHS.
Why do I think that? Mobil has a 0W50 for racing with lots of VM.

Buster and Overkill will love this post.

 

[ZeeOSix]

With VMs, an oil can have the viscosity it needs at high temperature without an unnecessary boost in power robbing HTHS.

The measured HTHS is what it is regardless of how the oil if formulated. But the oil formulation can make oils with basically the same KV100 have somewhat different HTHS viscosity.