OT: What oil to us in Chevy 3500???
 

Here is the issue, albiet small and almost insignificant. I have got a 1998 Chevy 3500 4 door dually with the 7.4L 454. The owners manual and sticker on the radiator (of all places) says to use only 20-50 motor oil. The guys a the Jiffy Lube have been putting 10-30 in the truck. I didn't see anything wrong with it but now I am questioning whether I should stick to the manufactuers spec of 20-50. What do you think, or more importantly, what do you use?

20w50 is needed in that motor for several tech reasons (clearance Problems ) ect ,use a 15w50 mobile one or amsoil product any easy to get synth. oil

Thanks Bobby! I will be putting that in in about an hour.

I have the same truck, but an '00. The oil cap says to use 5w-30.... WTF?
I've been using Valvoline 20/50. The engine is quiteter than when I ran 10w40...
I change it every 4000 miles, and the 20/50 always comes out still slick...
Come on man.. this motor only runs out to 4500, if you wring on it. Most of the time it runs 2000-2500rpm. "Good" oil isn't so important in these low comp. slow engines...

I have the Banks Powerpack on mine... 350+hp, 500+ft lb. Yeah, it pulls good.

the motor is still loaded even at low rpm ,rpm doesn't have alot of affect on oil its heat (towing,stop and go traffic,ect) and load are the big problems ,people get away with alot ,I like the advantage
of syn.oil ,,,read the propaganda on redlines home page or mobile ,ect

i have a 01 gmc with a 496 manual says to use 5w-30w i prefer 20-50 any thoughts ?

So I went and got the 20-50 put in. I feel better about it. Haven't noticed any realy difference yet, but will keep you posted.
: )

Hey Tim G Thats pretty sweet! I think my next purchase on the truck is to upgrade the existing 27 gallon fuel tank to 65.
I love the truck, I commute 50 miles a day eats up gas but I enjoy driving it.

the 496 is a tight motor and 10w30 or 5w30 is fine for it with and AC brand filter to stop or help stop noise when you first start it :D :D :D

Try different weights and let the oil pressure gauge decide whats too heavy or light.
In my 2000 crew cab 454 dually I ran 10w30 (5w30 was recommended, but I wasn't comfortable with that light an oil).
I now have a 2001 6.0L dually (boy do I miss my 454!) I run 10w30, 40psi oil pressure at any rpm above idle, 30 @ idle.