5W-20 question

[69 Riv GS]

5w-20 is always a highly debated topic around here.

quote:

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The common UOA's will show that the engine is fine, however, I really wonder what other things would pop up if you had a detailed more expensive UOA done.

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I agree.

Or in best case, performed a "tear-down".

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Sorry, I have a hard time buying that your mustang sees more abuse that any mod motor in any Ford Truck in general.

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There are different types of abuse.

A mustang, w/slicks, produces alot of engine stress "off the line".

High RPMs typically don't cause oil related problems given there's enough pressure. But extended high RPMs/speeds could heat a 20 weight to beyond it's limit IMO. 5.25 cSt is considered the minimum safe viscosity; for a 20 that happens at 212*F, a 30 at 257*F and a 40 weight at 302*F.

An other type of abuse is "lugging". This is hard to achieve without a manual trans, and/or towing an extreme load. And it could IMO give 20 weight a problem(low HT/HS).

FWIW,
I say the 4.6L in the stang is generally shown a harder life, given that most small work trucks/SUVS are automatics and that Mustangs are more likely to be "beat on" for any length of time.

 

[02supercrew]

quote:

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Originally posted by mf150:
I just had a friend blow a "bulletproof" 4.6L "PI" mustang engine (2002 GT). The oil that was in the engine when it blew: 5W20 weight Motorcraft.

20 weight may be okay for conservatively driven street vehicles, but if you are going to put any stress on that motor, go with a 30 weight.

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How sure are you that it was the oil it self?

Dont suppose you had a UOA done on the oil to actually determine if it really was the oil?

And if it was really the oil, there would be a whole pile of cratered motors as a result from that bad batch of oil that your friends motor got.
Seems to me QS had something like this happen way back in the day.


Sorry, I have a hard time buying that your mustang sees more abuse that any mod motor in any Ford Truck in general.

I'm currenty looking at 5 V-10 service body trucks that all have over 250K on plain ole MC 5-20, and that's not counting the other 15 various mod motor trucks we have, all have more than 70K each.

Not to mention all the good UOA's of MC 5-20 on this board.

 

[mf150]

I guess the jury's out on 5W20.

Whimsey, thanks for the advice on the 10W30 Red Line. That is a good point. I've heard several techs. talk about smaller clearnces in the PI'd engines, but when I asked them which clearances changed in the 99+ (Mustang) years, they couldn't tell me. Sounds like BS from Ford. At 20,000 miles, I'll switch to 10W30 possibly.

That's the viscocity that we are running in our 97 Lariat F-150. We are running Mobil 1 10W30, which has worked out well in the 4.6.

69 Riv-- a very realistic critique about the manual vs. auto delemna. A manual will possibly expose an engine to higher levels of stress than an auto...with rev limiter, etc.

 

[TallPaul]

I think full (and true) synthetic 10w30 is a good way to go in these 5w20 spec'ed cars. Another thing about the manual tranny is the entire drive train from rear tires to engine bearings will get a greater shock load with a clutch than with the somewhat dampening effect of a torque converter--or so it seems, but maybe not so if you have a racing type torque converter.

 

[Steve S]

This is my thought
on 05w/20 oils ,on the uoas on the board have been ok but if a 10w/30 shears to a 20 if left in a bit too long what would happen to a 20 if left in too long?

 

[mikep]

quote:

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Originally posted by Steve S:
This is my thought
on 05w/20 oils ,on the uoas on the board have been ok but if a 10w/30 shears to a 20 if left in a bit too long what would happen to a 20 if left in too long?

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Well we've already seen that most of the 20w oils are staying in grade given the same OCI as some xW-30w oils.

As with anything, your mileage may vary

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[Motorbike]

Other than the Motorcraft the 5w-20's are shearing to the low, low 7 cSt's . Search Pennzoil 5w-20 in the UOA section . It starts at 8.6 per their website .

The dino 5w-30's on the other hand run down to around 9.4 from an average starting VI of 10.2 .

9.4 is obviously near 2cSt's thicker than a sheared 20wt . I'll take the 30wts especially to lighter ones even though Ford designed and or uses a harder bearing shell and bumped the oil pressure up ..... temp vi shear is still , temp vi shear

Now a good PAO/Ester 20wt might be a different story .

JMO

 

[dustyjoe1]

I've tried torco, Mobil 1 and amsoil g3 and pennzoil dino in my honda (20wts). The synthetics were good, the pennzoil too volatile (needed to add oil at 3500 miles). The synthetic oil cost me roughly 20 bucks for a change. I am currently using motorcraft; 4500 miles, no oil added, still going strong (imo). the oil cost me 6.15. Why spend 20 bucks on a synthetic (5-6k oci) when you can get the same results out of motorcraft oil for 6.15. In my 6.5 quart sump fords that's 35 bucks for synthetic and 10.76 for motorcraft. Synthetic might be better in the extreme, but for everyday grocery getting, its hard to justify the extra expense.... IMHO

That said: If I was racing , stang or otherwise, the only reason I can think of for using a 20 weight would be for reduced frictional losses. But I think I wouldn't even consider getting a 1.42 oil to do the job. If you are going to use 20 weight for racing get something like redline or equivelent racing oil.