Older car? thicker oil?

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Originally Posted By: edwardh1
If a car NEW uses 5w 30, when it gets say 110,000 miles on it should you put 10w 40 in it? to compensate for wear?
seems there is SOME wear in 100,000 miles.


Think of it this way: The trend to 5W20 oils, so keep the 5W30 and you will be using a thicker oil...
 
Originally Posted By: Captain_Klink
In my GM owner's manual for a 3.4l 6 cylinder, the engineer writes it out: DO NOT USE ANY OIL THICKER THAN 5w30. Obviously, going thicker is a problem, and the only problem i can think of, is your engine is going to experience accelerated wear and premature failure. (is there any other significant problem they could be thinking of?). i don't think this is misinformation at all.


Your manual probably also states that 10W30 is acceptable down to 0*F, just like my GM owner's manual.

The only problem you can think of is accelerated wear and premature failure? So you post it as fact?

How about a possible mileage penalty? Or the fact that the average person is an I-dot, and will run 20W50 in the dead of winter.
GM puts that in the manual to cover their bum.


Originally Posted By: Captain_Klink
the main problem with oils, is that they are too thick. during the running phase, when a heavy oil is hot, probably it can lubricate alright, but as you know, a car gets turned on and turned off all the time, and during the time it takes to get hot, the oil is too thick.


A heavy oil can probably lubricate alright? Give me a break man. You really need to step back from Dr Haas. The UOA's of my trail Jeep running 10W40 and SAE30 with CONSTANT start/stops, long periods between onstacles, and extended periods of idle had single digit Fe numbers in an engine design known for iron.

So, what does that prove? Does the thicker oil cause start up wear or is it the fit of the cold components in an engine when it's first started?
IMO, it's the latter. Obviously I'm not going to run SAE50 in winter, but starting my engine with 10W30 (or even a 10W40) well above zero, is perfectly fine.

The bottom line, is that thicker oil is not the devil. Otherwise, I'd be replacing engines every year up here in the North East or shipping gobs of 'em over to the Aussie's.
 
IMO, it's the latter. Obviously I'm not going to run SAE50 in winter, but starting my engine with 10W30 (or even a 10W40) well above zero, is perfectly fine.

Thats my situation in south carolina, hardly ever start at less than 35 degrees
 
ok, let me throw this in the mix, say im taking my 5.3 silverado on a 500 mi trip one way, its dead summer 80-90 degrees, 70-75 mph interstate driving, only stopping for fuel. factory calls for 5-30 but i want to bump up protection so i mix 4 qrt 5-30 and do 2 qrt's 10-40, obviously im thickening things up a tick. good idea, bad idea ? ive never done it but its crossed my mind.
 
How is your oil pressure? At least the -40 should help the warm engine. Your plan makes more sense than on another site where somebody is suggesting 10W-30 in place of 5w-30 in an older engine.
 
Originally Posted By: labman
How is your oil pressure? At least the -40 should help the warm engine. Your plan makes more sense than on another site where somebody is suggesting 10W-30 in place of 5w-30 in an older engine.


My oil pressure is perfect, warm idle is around 40, and 50psi at 1,500rpm normal opperating temps. My truck in general is in perfect operation, im just always thinking ahead and ways to add protection in different situations.
 
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Only if you need it. Baring extreme war to the oil pump or mains from running low or guid wear being excessive ew cars built today shoul dautomaticly need thicker oil as they age. My wife ran her car out of oil because the sender went bad and it was bumping out the block rather fast. She did not kill it the rods and mains seemed to survive just fine but I suspect she aged the oil pump a lot that day!!!! I suspect the backing plate for the Gerotor oil pump on her Buick 3.8 took a beating!
 
Just pokin the bees nest here; but I hear a 5W40 in winter is better than a 10W30.
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I run 10w30 M 1 all the time, 200,000mile on a 318 dodge,2002, no oil usage yet, doesn't drip etc, no weird engine noises, manual says to use 10w30, when in doubt, read ur owners manual, they never say a thing about bearing wear and using heavier oils., oh the days of the 60s when folks traded every 50, ooo miles or so, didn't have to worry yourself sick over oil thickness,,we only had 30 wt most of the time, maybe 20 wt in cold weather. Dad had an old 60 model Plymouth 318 then, we never had problems with that engine,,,o boy,,history repeats itself,,now I'm driving a van with the same engine,,works for me,lol...............
 
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Originally Posted By: OtisBlkR1
Originally Posted By: labman
How is your oil pressure? At least the -40 should help the warm engine. Your plan makes more sense than on another site where somebody is suggesting 10W-30 in place of 5w-30 in an older engine.


My oil pressure is perfect, warm idle is around 40, and 50psi at 1,500rpm normal opperating temps. My truck in general is in perfect operation, im just always thinking ahead and ways to add protection in different situations.


If 50 psi is your bypass pressure, thicker oil will just move through the engine slower before dumping out the bypass. If the bypass is right near the pump the rest of the motor will get LESS flow, not a good thing.
 
It depends on the engine, the mileage, and the condition of the engine along with driving style/habits.

Nothing else.
 
Originally Posted By: Jaymus
It depends on the engine, the mileage, and the condition of the engine along with driving style/habits.

Nothing else.


i would tend to agree, i cant see doing any real damage with my suggestion.
 
Originally Posted By: Michael_P
Just pokin the bees nest here; but I hear a 5W40 in winter is better than a 10W30.
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Only if you run your Porsche hard in the Alps; otherwise for regular pass car NOWAY.
 
Originally Posted By: ARCOgraphite
Originally Posted By: Michael_P
Just pokin the bees nest here; but I hear a 5W40 in winter is better than a 10W30.
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Only if you run your Porsche hard in the Alps; otherwise for regular pass car NOWAY.


LOL, today it was -16C and the 5w40 in my 5w20 spec'd 5.4L was flowing just fine
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Well, if you want to waste gas churning oil. Most PC could run xx-30wt viscosity. I do like a bit thicker oil than a thinner myself - so what am I doing!!!
 
Originally Posted By: ARCOgraphite
Well, if you want to waste gas churning oil. Most PC could run xx-30wt viscosity. I do like a bit thicker oil than a thinner myself - so what am I doing!!!


I love the churning! Instead of butter, I get little Exxon-Mobil shareholder certificates, LOL!
 
So you guys think a 5W-40 (Grp III) synthetic is thicker at 0F than a 10W-30 conventional?

I can go in my garage and shake some RTS 5W-40 and an old bottle of Castrol GTX 10W-30, both with just a bit in the bottom, and definitely tell the RTS 5W-40 is much more watery.
 
Originally Posted By: Jaymus
So you guys think a 5W-40 (Grp III) synthetic is thicker at 0F than a 10W-30 conventional?

I can go in my garage and shake some RTS 5W-40 and an old bottle of Castrol GTX 10W-30, both with just a bit in the bottom, and definitely tell the RTS 5W-40 is much more watery.


I sure didn't state that
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Though I think ARCO might be implying it!
 
I just can't tell if this is some old joke I don't get, or if someone is really saying 10W-30 is thinner than a 5W-40 syn at cold temps like 0F or 5F.
 
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