"thin" oil debate and strawmen

[UNC017]

I think both "sides" use strawmen to some degree. But really, doesn't the argument MOST OFTEN arise when someone (usually in North America) says something to the effect of, "I just don't think 5w20 that my manual calls for can possibly protect as well as 5w30, wouldn't I be better off running 5w30?" So naturally you see more defenses of thin oil since its more often questioned.

Now when someone asks about a 1960s big block and wants to run 0w20, you might see some strawmen on the other side ;-)

Generally I try to respond with reasoned arguments about engine architecture. 5w20 vs 5w30 really probably WON'T matter a hoot on most modern engines. But a thin oil in a vintage big-block Chevy or AMC 390 that only runs 40 psi oil pressure on thick oil and expects it to ooze over the rocker arm ball studs depending heavily on oil film strength... well, that might not be the best application for a thin oil.

What I get really sick of is people claiming that North American CAFE rules are the SOLE reason for thin oil. I agree those rules are a part of the reason, but I don't think they're the only reason by a long shot.

 

[dave1251]

I will piggy back 440Magnum's post a little. If I am measuring oil pressure throughout the engines RPM spectrum and a 20 grade oil is providing specified oil pressure from the manufacture and along with my oil temperatures are not exceedingly high like rarely exceeding 100C why would I trade off with a higher grade of oil to obtain more pressure? How does that benefit the engine?

 

[SwampSurvivor]

I live in NY state. The car is going to rust in half before either 0w-10 or 20w-50 would cause engine failure

 

[Brigadier]

I actually worry more about wear due to the removal of anti-wear additives to meet pollution standards. My truck is not under warranty, and therefore will be getting Red Line 0W30 from here on out. It is not certified to 6094M which is the only spec my owner's manual requires, but who cares. I am sure it will beat it with flying colors.

As an engineer, I have learned, and seen first hand, how extremes usually do not give the desired results. I believe the multi-vis 30W oils are generally the sweet spot of lubrication and protection. There are exceptions of course.

I BELIEVE[not feel] that too many people think 'if a 30W oil results in better fuel economy than a 40W or 50W oil, then a 20W or even a 10W oil will be even better, right?' Maybe, but what about wear?

Conversely, those that think 'if a 30W oil gives better protection than a 20W, then a 40W or 50W oil is better, right?' Hmmmm.....maybe.

I believe there is a bell curve of oil weight vs protection, and 30W is in the middle - the sweet spot. Again, this is for the average commuter car, not a BMW M5, Corvette, Porsche, Ferrari, etc....

 

[ARCOgraphite]

Most of my engines are too noisy for my liking on a thin 20. I Equate noise with impending doom, so staring this year, I plan to adjust viscosity (and zinc) to where Im comfortable - regardless of service life or minor MPG impact. If the engine is burdened by windage then Ill want to adjust to a lighter viscosity.
AFA failures, I would think only the manufacturer have good data on service life under warranty - and they are not letting US know anytime soon. So no valid data in the public realm that Im aware of - sorry.

 

[Brigadier]

Originally Posted By: ARCOgraphite
AFA failures, I would think only the manufacturer have good data on service life under warranty - and they are not letting US know anytime soon. So no valid data in the public realm that Im aware of - sorry.


Agreed. Once the engine is out of warranty - 36k miles for most - the car owner is on their own.

 

[dave1251]

Originally Posted By: Brigadier
Originally Posted By: ARCOgraphite
AFA failures, I would think only the manufacturer have good data on service life under warranty - and they are not letting US know anytime soon. So no valid data in the public realm that Im aware of - sorry.


Agreed. Once the engine is out of warranty - 36k miles for most - the car owner is on their own.


36K for a engine warranty who offers that on a new vehicle?

 

[Y_K]

You ask why people prefer demagoguery to sound argumentation? It is a convenient shortcut, and the history of mankind could be presented as a history of shortcuts.

As for lubrication, I am with Mr Brigadier and his bell curve application.

 

[chubbs1]

Originally Posted By: Silk
I think they balance out - no ruined engines with 0-20....and no ruined engines with 20-50. I've heard noisier engines on thin oil, and bad shifting on motorcycles with thin oils, but no premature engine failures. You also get bad shifting with thick oils in motorcycles too....and good shifts with a non recommended grade.


Well said.

 

[UNC017]

Originally Posted By: dave1251
I will piggy back 440Magnum's post a little. If I am measuring oil pressure throughout the engines RPM spectrum and a 20 grade oil is providing specified oil pressure from the manufacture and along with my oil temperatures are not exceedingly high like rarely exceeding 100C why would I trade off with a higher grade of oil to obtain more pressure? How does that benefit the engine?


It doesn't. And might just hurt- for example: send filters into bypass when they don't need to go into bypass, trip the pressure regulator at a lower oil FLOW rate so that parts of the engine are starving for flow while others have adequate pressure.

Take my Ram 4.7. 80 fsckin' PSI on HOT 0w20 oil at speed, 20 PSI at idle, measured with a reliable mechanical gauge. And by hot oil, I mean hot after several hours of towing a trailer at 70 mph on I10 in west Texas in ambient temps of 105F and higher last summer. Now how on earth is that engine going to benefit from oil that is thicker, particularly in more ordinary everyday driving, provided that both oils have good additive packages?

But I'll be danged if I'm going to do the same with a 60s big-block or a German engine designed for thicker oil.

My point is that its not about the OIL so much as it is about the ENGINE design.

 

[buster]

Originally Posted By: 440Magnum
Originally Posted By: dave1251
I will piggy back 440Magnum's post a little. If I am measuring oil pressure throughout the engines RPM spectrum and a 20 grade oil is providing specified oil pressure from the manufacture and along with my oil temperatures are not exceedingly high like rarely exceeding 100C why would I trade off with a higher grade of oil to obtain more pressure? How does that benefit the engine?


It doesn't. And might just hurt- for example: send filters into bypass when they don't need to go into bypass, trip the pressure regulator at a lower oil FLOW rate so that parts of the engine are starving for flow while others have adequate pressure.

Take my Ram 4.7. 80 fsckin' PSI on HOT 0w20 oil at speed, 20 PSI at idle, measured with a reliable mechanical gauge. And by hot oil, I mean hot after several hours of towing a trailer at 70 mph on I10 in west Texas in ambient temps of 105F and higher last summer. Now how on earth is that engine going to benefit from oil that is thicker, particularly in more ordinary everyday driving, provided that both oils have good additive packages?

But I'll be danged if I'm going to do the same with a 60s big-block or a German engine designed for thicker oil.

My point is that its not about the OIL so much as it is about the ENGINE design.



+1

 

[accent2012]

Another good laugh. Thanks BITOG!

 

[kr_bitog]

Originally Posted By: 440Magnum

My point is that its not about the OIL so much as it is about the ENGINE design.



Agree, but I also believe the reserve wear margin is better with thick oil. I have just thrown away my Toyota 1NZ-FE after 150k km on 30 weight oil. There is no smoke but it burns oil like crazy, the last time I tried to flush, it spewed smoke.

The replacement comes with Prestone 5w-40 synthetic, interestingly it accelerates good and quiet. My old engine always feel sluggish with 40 weight oil.
So now still feel undecided whether I should go back to Mobil 1 Advanced Fuel Economy 0w30 or stick with Mobil 1 Extended Performance 5w30 or others.

 

[HerrStig]

My question is: how much interest does a manufacturer have in engine life beyond the warranty period? Now that the bureaucrats have imposed fuel economy and environmental protection "goals" on the manufacturers, which may or may NOT enhance longevity, are oil grade requirements being influenced by other than long life? Sure, a company or two are offering "100,000 mile" drivetrain warrantees, but, ahhhhh, read the fine print. I am not sure how happy the marketing droids are with folks keeping their cars 10 years or more. On the other hand, the "lease what you can't afford to buy" crowd doesn't keep the vehicles long enough for thin vs thick to matter. For my purposes, 5-40 T 6 covers a multitude of sins, including an airhead BMW bike.

 

[lexus114]

Originally Posted By: Pop_Rivit
Originally Posted By: tommygunn
Who cares?


Agreed.




Yeah....what they said!

 

[RF Overlord]

Not sure if this is relevant in the context of this discussion, but I used to run my '68 Buick Gran Sport on Valvoline Racing 20W-50 because, well...it's racing oil; it HAS to protect better than regular oil, right? And the motor has almost 200,000 miles so I NEED a thick oil to keep the pressure up, right? After joining up here, I came to my senses and started using Pennzoil High Mileage 10w30 (manufacturer's spec'd viscosity) I found that the oil pressure stayed about the same and the engine seemed to rev more freely. I kick myself for all those years I ran a thicker oil than necessary.

 

[Y_K]

Originally Posted By: 440Magnum
trip the pressure regulator at a lower oil FLOW rate so that parts of the engine are starving for flow while others have adequate pressure.

How, exactly, do you meter FLOW? I am interested in the metrology here.

 

[kschachn]

Well then, I'm going to say you had issues unrelated to "30" weight oil. My 1NZ-FE has had 0W-20 in it since Toyota OK'd the use, and either 5w30 or 0w30 for the rest of its life. It uses almost NO oil during a typical 8K OCI, and I have nearly 200,000 miles on it now. There's just no way if you used a quality oil and a reasonable OCI the viscosity of your oil made your 1NZ-FE "burn oil like crazy" and spew smoke. No way no how. The 1NZ-FE is a very forgiving and robust engine, nothing like the 1MZ-FE in my Sienna.

And what do you mean the last time you tried to flush it? Flush what, the engine? With what? That worries me right there you are using that term.

Originally Posted By: kr_bitog
Agree, but I also believe the reserve wear margin is better with thick oil. I have just thrown away my Toyota 1NZ-FE after 150k km on 30 weight oil. There is no smoke but it burns oil like crazy, the last time I tried to flush, it spewed smoke.

The replacement comes with Prestone 5w-40 synthetic, interestingly it accelerates good and quiet. My old engine always feel sluggish with 40 weight oil.
So now still feel undecided whether I should go back to Mobil 1 Advanced Fuel Economy 0w30 or stick with Mobil 1 Extended Performance 5w30 or others.

 

[TFB1]

Originally Posted By: Y_K
Originally Posted By: 440Magnum
trip the pressure regulator at a lower oil FLOW rate so that parts of the engine are starving for flow while others have adequate pressure.

How, exactly, do you meter FLOW? I am interested in the metrology here.

Exactly...

At 80-95 psi, the point where most systems are in relief(I refuse to call it bypass)even a 20W-50 on a freezing morning will be pushed through a opening the size of a ball point pen refill... No doubt a 5W-xx would be better choice, but likely the pressure relief valve is partially open with either oil...

 

[kschachn]

Also, what do you mean "go back" to 0w30 or "stick with" 5w30? They both are "30" weight oils.

Originally Posted By: kr_bitog
Agree, but I also believe the reserve wear margin is better with thick oil. I have just thrown away my Toyota 1NZ-FE after 150k km on 30 weight oil. There is no smoke but it burns oil like crazy, the last time I tried to flush, it spewed smoke.

The replacement comes with Prestone 5w-40 synthetic, interestingly it accelerates good and quiet. My old engine always feel sluggish with 40 weight oil.
So now still feel undecided whether I should go back to Mobil 1 Advanced Fuel Economy 0w30 or stick with Mobil 1 Extended Performance 5w30 or others.