Anyone use 10w40 or 20w50?

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Originally Posted By: umungus1122
Originally Posted By: turtlevette
For me the heavier oils are a problem solver. My 79 trans am leaks out of the rear main like crazy with 5w oils specifically M1 tdt. Straight 30, 15w-40s and 20w-50s don't leak a drop.

Exactly.

And I for one won't believe any grade of oil will stop a "crazy" rear main seal leak...

Reduce it somewhat, maybe...

I have 10W-40 Defy in my '69 Torino with 428Cj engine, the daily drivers will soon be on a diet of 0W-40 PZ Ultra...
 
Originally Posted By: Nick1994
Originally Posted By: ShotGun429
Always have run 15W-50 in Our Shop Truck: a 2002 Ford Ranger,4.0L SOHC. Which is one of the years with the Chronic timing chain/tensionor/Guide issues....that puts so many of these trucks and Explorers in the graveyard with the Death Rattle before their time..... Im nearing 160,000 miles with ZERO issues....Best Engine I have ever owned. Could It be the heavy oil??? Im convinced.
160,000 miles is hardly any mile at all. I've hardly ever heard of an engine problem on cars with 160k or less miles unless it's a GM intake manifold issue or a sludged up Chrysler 2.7L V6.


My wife had a new 2002 V-6 4.0 Explorer that was faithfully changed with Mobil 1 and Schaeffer's synthetic blend every 5,000 miles or so. At around 43,000 miles Ford confirmed the timing chain cassettes had failed, front and back ones. An UOA confirmed that huge amounts of iron was in the oil due to the chains slapping around. Traded it in for a new 2005 V-8 4.6 Explorer that she still drives daily and has 175,000+ miles on it and it still runs great.

Whimsey
 
Originally Posted By: car51
I sure as heavens don't know many folks that use these grades. Just curious if any members here do though.

My sons 96 Corolla has over 220K miles on it. He uses STHM 10W40 when WM is out of VML 10W30.
He just recently did a piston soak for 2 days on the engine. He used a home made brew of SeaFoam and Kreen. He would just add a few ouces every few hours. He then placed rags over the plug holes and turned it over to get rid of the excess. There was very little, meaning, it did a good soak. After running the engine for about 10 minutes he did an OCI with STHM 10W40.
Oh yeah, his neighbors were very upset with him for fumigating their homes.
grin.gif
 
So 0w20 is way more expensive ( more than double) than 20w50 and burns at least double. Hummmmmm. Thats at least 4 times more money ...

Environment, eh?

Cui bono?
 
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I have run 10w40 in my Jeep over the summer with good results and an excellent UOA to show for it.

Also ran SAE 30 PYB this last summer for kicks, no perceptible difference from 10w30 in the warm months, worked just fine.

I switch to thinner oils for winter for the cold crank abilities but otherwise see no advantage to them.
 
Originally Posted By: TFB1
Originally Posted By: umungus1122
Originally Posted By: turtlevette
For me the heavier oils are a problem solver. My 79 trans am leaks out of the rear main like crazy with 5w oils specifically M1 tdt. Straight 30, 15w-40s and 20w-50s don't leak a drop.

Exactly.

And I for one won't believe any grade of oil will stop a "crazy" rear main seal leak...

Reduce it somewhat, maybe...

I have 10W-40 Defy in my '69 Torino with 428Cj engine, the daily drivers will soon be on a diet of 0W-40 PZ Ultra...


The old Pontiac v8s have a rope seal. You have guys pulling their motors replacing these and getting leaks after time after time. That's a tremendous amount of work. I believe it does have something to do with the oil. It was undriveable and a gross polluter with light weight synthetic, leaving pie plate size leaks on the ground at every stop.
 
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Originally Posted By: turtlevette
The old Pontiac v8s have a rope seal. You have guys pulling their motors replacing these and getting leaks after time after time. That's a tremendous amount of work. I believe it does have something to do with the oil. It was undriveable and a gross polluter with light weight synthetic, leaving pie plate size leaks on the ground at every stop.

Oh the memories. I have had to use a "SNEAKY PETE" several times to replace these seals. Oh joy joy!
 
10W40 in my diesel. I have some 10W40 hdeo in my stash for it, the Selenia 10W40 was just for fun (the exact oil recommended by the sticker under the hood, lol).
I'll probably use 5W40 next winter.
 
Originally Posted By: userfriendly
Not all 10w40s should be painted with the same brush. .

Unless high oil pressure was my objective, I would pick a mono-grade SAE40 over 20W50 and an SAE 30 instead of 10W40. The mono-grades would not shear permanently or temporarily in use.

Thank you for your insight.

Towncar and taxi old-timers around me keep filling with 20W50 at Jiffy Lube for over 600k miles.
 
Back in the day, before we bought our first car for which the 5W-30 grade was recommended, I used 10W-40 in everything, except for old German cars which got 20W-50 during the summer and I did sometimes use M1 15W-50 in our '86 Civic Wagon, as well as in our '97 and '99 Accords. I used 10W-40 in our Vanagon as a winter oil and HD30 summers.
In 1997, we bought a new Aerostar, followed with a new Accord in 1999.
I took it on faith that 5W-30 would be fine for these engines, and it turned out to be.
These also got the occasional warm weather run of either 10W-40 or 15W-40.
Nothing wrong with thicker grades in practice.
I still use 10W-40 in my old BMW, which is actually too thin for the warmer temperatures in which I drive it according to the OM.
 
My Mercedes C220 has done over 300,000km on an exclusive diet of 10W40...it's usually semi synth here. 20W50 goes into my Airhead, and also my daughter's Ford Laser because it burns a bit and she never checks it.
 
Originally Posted By: aquariuscsm
I think tomorrow I'm going to clean the AZ here out of all their clearance pyb 20W50.


I tried and they were already sold out at three stores
frown.gif
 
Sure, why not?

Ran an OCI worth of Valvoline 10w-40 dino from a garage sale in my Accord a few summers ago w/o any bother whatsoever.
 
Originally Posted By: aquariuscsm
10W40 and 20W50 are the only oils I use.


I had been using 5w-20 and 5w-30s to the exclsion of ALL 10w-xx but no more, I learned 10-30 is what my Lexus Sc300 loves.
 
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Thinner is generally better for cold and hot oil flow. Its more about what kind of sustained oil temps you see in your driving.

My opinion GF5 gets you to a sustained 210F oil temp. Higher than that, use an ACEA c3 (European standard) xw-30 or an xw-40. This applies to most engines these days. C3, with its higher HTHS, covers you to around 240-250F, not uncommon when using an engine near or at its maximum output over 100mph

Sustained oil temps above 210F are unlikely in US driving under 80 mph (even in the summer).
 
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