oil weight

[s10GN]

what oil weight should i be running on a stock set up?
thanks

 

[Quiky One]

10w-30 is what the GM engineers designed it for.

Jason

 

[s10GN]

thanks

thats what i've been running but i have seen some posts of people running 20/50. I didn't know if i could run thicker oil?

 

[Quiky One]

20w-50 is to cover up a bearing tolerance issue.

20w-50 is also harder on the gears in the oil pump...stick with what GM engineers designed it for.

 

[87gninpa]

x2, stick with 10w-30 if you can. In my WE4 I run 10w-40 because its a bit higher mileage, but IMO 20w-50 is overkill.

 

[2QWIK4U]

15W-40 Rotella

 

[s10GN]

thanks i will stick with the 10/30

 

[we4Mateo]

I've been debating about going heavier too as a lot of "builders" on this board state it makes their engines last whilst being raced. If clearances are right though, then the extra oil psi from heavier oil would logically wear the pump faster I would think. My oil pressure is within spec at hot idle and at wot though, so I'm leaving well enough alone. I also just took my motor apart and wear was minimal after 65k+miles all on 10W-30 so I'm sticking with it.

 

[GARY HARVEY]

Whatever oil + ZDDP

 

[we4Mateo]

Whatever oil + ZDDP

x2...I forgot to mention that I've always run ZDDP and have had no issues with flat tappet cams either stock or current (2k+ on current and 12 passes).

 

[frank700]

Rotella 10w-30 perfect for these engines.

 

[GARY HARVEY]

Excellent choice along with the newer T6 synthetic 10W-40.
Also handy that the same Rotella works equally
as well in my 1 ton HO work truck (360K)
and it runs better than when new! :biggrin:

 

[we4Mateo]

I've always heard that Rotella doesn't have the right detergent package for a gasoline engine. Diesel engines have very different contaminaets to deal with and a different operating environment. Just add ZDDP to your favorite gasoline oil. Works every time.

 

[GARY HARVEY]

I agree completely in reference to the blends used in years
past but things change and oil blends are included.
The current synthetics are a different animal
and Rotella T6 does have an API-SM spec.
NOTE: JUST REMEMBER THIS STUFF HAS NO ZINC, so remember the ZDDP !!!

 

[lgonzalez_1986]

if your goning full synthetic go with ams oil its a bit expensive but for once year or 12,000 mile you cant beat it and theres one with the zinc already in it!

and as far your viscosity 10-30 was 25 years ago a new car from the assembly line! you can go with higher levels when seals start to wear away, high mileage vehicles run thicker oil

older=thicker unless you have low mil. gn and rebuilt engine and or performance engine

also some oils wont break down as quickly at higher heat levels!

 

[GARY HARVEY]

AMS Oil is good stuff but a little hard to find (sometimes) and not the same as when it was first developed (I used to sell the stuff 20+ years ago btw). NEO is the only full ester oil stock unless things have changed recently (if you can afford it). Royal Purple is easier to find and has the market share etc. (I wish I owned some stock). As for "old" motors, I'd guess the percentage of untouched V6/3.8s is getting to be a rarity (my front cam bearing went out at 144K many years ago) and I was using 10/30 AMS OIL for the whole trip..
High mileage and going to a heavier weight base with higher mileage has been argued longer than "which came first, the chicken or the egg". My 02' F150 has 175k and runs better now than it did when new and I'm not about to argue with Ford's decision to designate 5/20 (also doing oil samples indicating no out of speck areas of concern) with Royal Purple which seems to be more than adequate and if it does give up the ghost tomorrow, I wouldn't have grounds to complain since Ford would most likely have a good laugh with this mileage, if I did >).
Use the oil you prefer and change the weight too, it doesn't concern me in the least.
I've been doing this since the 60's and will continue to be amazed at the advances being made with lubricants and doubt very seriously ANYBODY on this forum has more miles under their belt, having run more than 2.3 million miles with my last (Series 60 Detroit 400) Peterbuilt which was purring like a kitten when I sold it in 2001 and retiring from living in a truck (and I'm still in the business).

 

[BlackBandit]

there is a pressure spec for our engines. If your engine is stock or factory spec and you can pass the factory spec with 10w-30 then run 10w-30. Don't just pour in heavier oil because you have miles on an engine. Going by that thought process I should be puttng gear lube in my 300K+ rabbit diesel. Of course if you're going to road race it or use it for something way off of normal usage (like endurance racing) you may want to change. But for daily driving with the occasional pass at the strip I would defer to the reccomendation of the people that designed the engine.

 

[lgonzalez_1986]

I would use 10-40 minimum on high mileage, and I'm not talking about high mileage newer cars I'm talking about old 300 k gn, I think w is heated oil which warms up faster and equals less wear, colder oils like sae I believe faster wear and tear!