dumb simple question - higher wear with thick oils

[JHZR2]

Hi,

I know Ive read it on here before, but I searched, came up to the 300 results, and didnt find what I was looking for.

Sometimes, one can determine that an oil is "too thick" because of elevated wear metals. What are these metals that you would look for, and why would them showing as elevated indicate that an oil is too thick (I assume flow)?

Thanks very much,

JMH

 

[Pablo]

I suppose concentrating on folks who live in very cold places and running "thick" oils, may help your search - but if the answer was that easy we wouldn't debate it so much!

I also think we have backed into the answer by claiming that thin oils don't cause excessive wear! (yikes)

 

[JohnBrowning]

You have to use some not so common common sense. The same wear metals are used to determine if the oil is too thick or too thin. If you have 5W20 in your car and lead is higher then iron then you need a thicker oil. If you have 25W70 in the engine and lead is higher then iron you probably need a thiner oil!It should also be fairly logical that the colder the ambient temp the lower the W rateing you will need with in the rated temp range for each rateing!

Generaly if someone is dumb enough to put an SAE 30W HDO or 25W70 with -F° temps. on the way his or her bearings will let them know! So will the valve train.In some cases the oil will be so thick the engine can not even turn over.

The big number for winter selection is the number in front of the W. The next number of importance is the HTHS and that is always a factor. If you get an oil that is shear stable and has the right W rateing and an HTHS that makes your engine happy everything else is academic!All engines will show a preferance for a certain HTHS.

Some get a little too caught up in the spec. with no real world trials to back it up! Many would think that one of the thickest 5W40's on the planet would not be apropriate for winter use. I on the other hand used it in temp.'s down in the -25°F range with temp at time of cranking being -18F°. I ran Redline 5W40 all winter long and never had any problems at all! It started and ran just as easily as my latter experiment with 0W30. The Redline had an HTHS of 4.7 while the M1R 0W30 had an HTHS of 2.9. It never got cold enough for the 0W30 to do anything for me that the 5W40 was not already doing well!

 

[427Z06]

quote:

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Originally posted by Ray H:
...The yard maintenance supervisor specifically expressed unease at apparently accelerated wear running these cars on Ford's recommended Motorcraft 5W-20 motor oil based on fleet UOAs...

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There's also the possibility this guy is confusing a measureable difference in wear metals with an actual significant difference in wear.

 

[JohnBrowning]

Well if he has a fleet of 12 cars and is doing UOA on them it ought to be evident if wear metals are going up or down!Part of it could be his personel beliefs or it could be all UOA based. Until we see the UOA from this fleet we have no idea if this guy is right on or way off base!

 

[jsharp]

I'll be really surprised if he sees much difference. His 10W-30 MC dino is going to be a 20 weight for much of the run anyway.

 

[mechtech]

OK - I suppose the yard supervisor go the job after many years of service - he's no kid.
That means a high probability of 'old school' thinking.
I doubt he is conversant in modern oil attributes.
Like 427 stated, what would the difference have been with 5-30 or 10-30, under those conditions?
Maybe there is a substandard oil filter problem.

 

[Ramblin Fever]

quote:

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Originally posted by jsharp:
I'll be really surprised if he sees much difference. His 10W-30 MC dino is going to be a 20 weight for much of the run anyway.

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So, you're saying there's no difference in running a 5w-20 versus a 10w-30?

If that's the case, then what's the point in having all of these different viscosities available on the market and why all the questioning about should I run a 5w-20 or a 5w/10w-30.

I'm just curious, as all this information gets "confusing"

 

[the_oil_dealer]

really though, you can't expect to run a 20wt in heavily used vehicles, which are punished quite often, and expect it to protect better than a (logically) more shear stable 10w-30

 

[Ray H]

Not to pour oil on a burning controversy, but our local constabulary noted in the minutes to this week's city council meeting that maintenance on the city fleet of Ford patrol cars (all 12 of 'em!

) would henceforth be confined to use of Motorcraft 10W-30 motor oil once the present stock of Motorcraft 5W-20 motor oil is exhausted. The yard maintenance supervisor specifically expressed unease at apparently accelerated wear running these cars on Ford's recommended Motorcraft 5W-20 motor oil based on fleet UOAs. His concern is understandable given the gravity of answering numerous emergency calls from the town's only Winchell's - must be emergencies since at any given time there're usually three patrol cars parked on the premises . . .

 

[427Z06]

That question is sure to re-ignite another firestorm of debate.

However, one place you may find your answer is with engine rebuilders in the northern latitudes. When they disassemble engines, ask them how easy it is to determine which engines were driven for an extended period of time with a thermostat that was stuck open or missing.

 

[427Z06]

quote:

---

Originally posted by Ray H:
... but our local constabulary noted in the minutes to this week's city council meeting that maintenance on the city fleet of Ford patrol cars (all 12 of 'em!

) would henceforth be confined to use of Motorcraft 10W-30 motor oil once the present stock of Motorcraft 5W-20 motor oil is exhausted...

---

Interesting. So have they been running 6 cars with 5w20 and 6 cars with 10w30 from the time of delivery?

 

[haley10]

Seems like too thick in a cold climate would result in problems immediately noticeable, such as problems with hydraulic lifters or breaking the oil pump.

In less extremes, I think the wear metals associated with valvetrain wear would be most obvious. That would depend on the metallurgy of the specific engine, and whether it has a belt or chain. I'd think high Fe could be expected, but you have to know the metallurgy of the upper end components you were starving.

 

[Pablo]

Ray H. - PLEASE beg him (with a baker's dozen) for copies of the UOA's!!! That would be sweet.

427Z - excellent point.

 

[mdocod]

i think the filtration should be looked at before the oil weight- though, police cars are typically driven harder than the average, I would suspect a "30" weight would be better for these engines than a 20wt in the long run.

 

[jsharp]

quote:

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Originally posted by the_oil_dealer:
really though, you can't expect to run a 20wt in heavily used vehicles, which are punished quite often, and expect it to protect better than a (logically) more shear stable 10w-30

---

That's the problem. The dino 5W-30's and 10W-30's don't seem to be more shear stable. Quite the opposite in fact. From what we've seen in the UOA section lately, the 30 weights become 20 weights in as little as 2K miles. The 20 weights OTOH seem to hold their viscosity well.

It starts to make sense why automakers are specifying 20 weight oils. Because if they specify a 30 weight, in just a few miles it is a 20 weight. So why not just go with something that starts out as a 20 weight and doesn't shear down over it's life. They get the minor fuel economy benefits up front that way too, along with possibly avoiding the sludge problems commonly associated with sheared VI's.

I'm not saying I agree with this approach, just that I believe that's part of the reasoning behind it...

 

[jsharp]

quote:

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Originally posted by Ramblin Fever:
So, you're saying there's no difference in running a 5w-20 versus a 10w-30?

If that's the case, then what's the point in having all of these different viscosities available on the market and why all the questioning about should I run a 5w-20 or a 5w/10w-30.

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Don't feel badly. I'm starting to wonder the same thing about the dino oils, at least the PCMO's. The rating on the bottle tells us where the oil viscosity starts out. The only way we know where it ends up is by an UOA.

 

[Blue99]

Dino 5W-30 & 10W-30's are designed to shear to pass the GF-4 fuel economy test. This is the tried & true method for meeting the 1-2% fuel economy gain versus the 5W-30 PAO reference oil.

But, remember, it is the long chain, polymeric viscosity improvers that are providing this shear.

The xW-30's may start at 10.5 and shear to 9.5/9.8 cSt, but this is still higher than the typical 8.5 cSt starting value of a 5W-20.

 

[427Z06]

Unscientific sampling of dino 5w20s and 5w30s from the UOAs:

code:

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Castrol GTX 5W-30 3340 miles 9.2

Castrol Start-Up 5W-30 4869 miles 9.4

BradPenn 5w-30 3928 miles 8.7

Chevron Supreme 5w-30 3003 miles 9.3

CANADA SUPREME 5w-30 6700 miles 8.9

Castrol GTX HM 5w-30 3000 miles 8.2

Havoline Supreme 5w-30 4036 miles 8.4

Valvoline 5w-30 2500 miles 9.2

Chevron Supreme 5w-30 3500 miles 9.1

Exxon Superflo 5w-30 937 miles 9.2

Castrol GTX 5W30 5w-30 3805 miles 8.2

Average 8.9

-------------------------------------

Motorcraft 5W-20 2579 miles 7.7

Havoline 5W-20 1918 miles 8.4

Motorcraft 5W-20 6600 miles 7.3

Motorcraft 5W-20 1744 miles 6.9

OEM 5w-20 6419 miles 8.2

Valvoline 5W-20 3000 miles 8.2

Castrol GTX 5w-20 3020 miles 7.6

Castrol GTX 5w-20 3007 miles 8.0

Motorcraft 5W-20 2246 miles 7.0

Castrol GTX 5w-20 4376 miles 8.0

Valvoline 5W-20 4230 miles 8.7

Average 7.8

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Some observations. Seems like the 5w20s suffer less permanent shear than the 5w30s. MC 5w20 seems to skew the 5w20 results. But in general, the dino 5w30s will end up with a higher KV100 after service.

 

[Big O Dave]

Excellent chart! Thanks for the work that went into it.

It seems that Chevron Supreme does pretty well, yet its "sister" oil (Havoline) doesn't do quite so well. Hmmmm...