Has anyone used 0/5W20 in an old engine?

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I did a 5w20 run one OCI on my '92 Saturn when I was short tripping it. Didn't seem to run any better (or worse), but repeatedly got an extra 8-10 more miles on a tankful than 5w30.
 
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The OP wants to hear from those who have. In the case of Gary's testing in his Jeep, he wanted to see how a thinner lubricant worked in an engine that typically shed a bit of iron and preferred higher viscosity.
Sounds like that can be devastating 🤷🏽‍♂️
 
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Ambient temperature still affects oil temperature. Many manuals recommend a thicker oil while driving in high ambient temperatures.

Your cooling system is designed for every day driving, regardless of the outside temperature.
 
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Let's hope this thread doesn't turn into a thick vs thin war.

I was wondering if someone here ever used a 5W20 or 0W20 in the long run in an older engine (say from the 90's) for which a 30 or 40 grade oil is specified. I'd like to hear from those who tried it.

Let's take engines i have experience with as examples : Mercedes M111 engine, 4 cylinders, DOHC, duplex roller timing chain. Or the M112 engine : V6, OHC, 18v, duplex roller timing chain. What it so different in these engines from other similar engines from a japanese or american manufacturer that spec a xW20 oil? They're quite basic engines. Does they need a 3.5+ HTHS or is it just because of ACEA and their hard-on for high HTHS dual rated oils?

I don't plan on running such oil in my cars but i've not seen much about running a 20 grade oil in an old engine, especially in a MB, BMW or VAG engine and i'm curious. To my knowledge, user HTSS_TR did run M1 0W20 for many years in his E430 with a M113 engine but that's all i've seen.
I've mostly run 5w20 in my 08 Jeep 3.8. That's what is specified. But I've swithched to 0w20 because I think it is better oil. 158k miles and it runs like new. It has Mobil 1 EP 0w20 in it right now. Next OCI will see either Chevron Pro DS 0w20 or Shell RGT 0w20 from the stash.
 
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Your cooling system is designed for every day driving, regardless of the outside temperature.
Cooling system will maintain the temp within the block (where the antifreeze circulates, etc). Thus why some high performance cars will have either stock or aftermarket oil coolers.
 
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Cooling system will maintain the temp within the block (where the antifreeze circulates, etc). Thus why some high performance cars will have either stock or aftermarket oil coolers.

This is the reason I use 2-electric fans plus a oversized aluminum radiator for my 500 horsepower supercharged mustang. Nothing to do with my choice for oil.

It's two completely different situations 😂
 
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This is the reason I use 2-electric fans plus a oversized aluminum radiator for my 500 horsepower supercharged mustang. Nothing to do with my choice for oil.

It's two completely different situations 😂
Nice!(y)

A lot of modded twin turbo Z32 owners will swap out the oem fan for the two electric fan setup.
 
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I tried it in a 93 Aerostar with the 3.0L engine when 5W20 was the rage here years ago, and Ford supposedly back-spec'd the engine for it. I decided I was better off sticking with 5W30 which got me to 200K miles. Going forward I switched both my Jeeps originally spec'd for 5W20 to 0W30 or 5W30.
 
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Yeah I put some 5w20 in my beat to heck 1994 dakota 3.9 because I got it on sale. Forget my reasoning, maybe figured it was winter and I was only driving a 6 mile round trip drive to the dump. Anyway the oil light came on at low idle, so that ain't good.




I also used it in an 05 prius (manual specs 5w30) with 250k+ miles and had no issues at all. Toyota back-specced it for that motor.

Interesting as the pressure stayed within limits the whole time.

That light looks like the level light.
 
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The tach is clearly not accurate. The RPM is audibly around 650RPM.
I guess it sounds faster when I crank the volume up. Perhaps, it is a low oil level warning as others said. There could also be an oil leak at the oil-pressure switch, which can result in a false lighting of the lamp. The latter happened to me.
 
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A member ‘OriginHacker21’ used to run a lot of 20-weight oils in his 2004 Pontiac Sunfire that called for 5W-30 (2.2 Ecotec).
He is long gone; but search the username and he posted a TON of UOA’s and observations on lighter oil in the engine.
 
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