I bought a 98 SS M6 recently. It has around 90,000 miles on it. I'm not sure of the kind of oil used previously. Should I use Mobil 1 10-30? The engine seems to be in very good condition, I just want to use the best.

 

I always used 5w30 but 10 should be fine!

 

I bought mine with right at 80xxx put regular castrol 5W-30 in it and noticed it started using a bit. Most likely the engine is using a bit I was told it had Mobil 1 its whole life so I put that back in. If it keeps using that ill switch to 10W-30 and plan for a rebuild when its time. I think I am actually looking forward to that

 

im pretty sure you can disregard the first number because it has to do with freezing temps...

 

go with a 10 or 5w40 its better for the engine, a little thicker

 

I've been using 0w-40 actually... I forget exactly the reasons, but it came out of a bunch of threads a while back about what oil to use. A number of really knowledgeable guys who'd participated in motor oil studies and the like, and came out saying that Mobil 1 was not the best choice of oil for the LS1. But there are a lot of dedicated Mobil 1 fans around (not me... I just can't easily get the better recommendations, and I'm fine with Mobil 1), so the general advice was that IF you're going to use Mobil 1, 5w-40 or 0w-40 is the way to go... the -30s are apparently thinner than other brand -30s, so go -40 to compensate. The other recommended oils were various Amsoils, Royal Purples, and German Castrol.

I'm not an expert though, not by a long shot... I was just going off what other people were saying. Search for threads about oil and you should find a lot of different opinions, or go to www.bobistheoilguy.com, they have a TON of information about motor oil there.

 

10w-40

 

Mobil 1 5w-30 with 6oz Tufoil. I have been using it on all of my cars (Chevy Malibu, Lesabre (79'), 91 buick regal, 2001 trans am ws6, 99 venture.)

The LS1 likes the thicker oils, as thats why castrol 0w-30 and 0w-40 works also.

the mobil 1 and Tufoil raises the cSt of the oil overall to around a 14.x, which is what the ls1 likes.

its really up to you what to use...personal preference

 

I've always used Mobil1 5-30, never had a problem. I hear about these guys going crazy over German Castrol or something. It's hard to find and probably expensive. Seems kinda crazy to me when Mobile1 is just fine.

 

Isn't Mobil 1 what comes in the pan of Vettes?? I would think if it's good enough for GM it's good enough for our cars. Of all the oil studies, I think the general would put the best in the pan. Personally I use the 10-30, sometimes 10-40.

 

Thanks for the input, I plan to use Mobil 1 in my next oil and filter change. Thanks again!

 

Mobil 1 0w40 SUV and Truck works pretty well.
Castrol 0w30 "made in germany" is the best.
Amsoil or Redline 5w40 are also going to do very well.

in order =

the german castrol
amsoil
redline
mobil 1


as tested in oil analysis of all 4 oil for breakdown.

 

Royal Purple 5w30, 165,032 miles and still going strong.....enough said!!!!

 

Mobil1 10w-30 in my 98 SS.

 

Hey, do you know if the 2005 batch of German Castrol is as good as the 2004? I heard they changed the composition, and haven't really heard much about people's results with 2005 GC.

 

Where are you guys finding 10 40 Mobil 1? All I can find is shitty 10 30.

 

german castrol 0w30 or mobil 1 0w40(synthetic of course)....Talk to Patman, he has tons of info on why

 

ok, if you are gonna use Mobil 1 (its a great oil) use 0W-40. I have used it for almost two years now, and I have noticed a small increase in fuel mileage, and slightly lower running temps as well as higher constant oil pressure. The 0 stands for viscosity (the lower the better) and 40 is the weight. Since it is a 0 viscosity, it flows better than a 10 or 5 and since it is a 40 weight it protects better at higher temps and rpm's. This a great oil for the price! I have been very happy with it, and I STRONGLY reccomend it.

 

Patman is the one to go to. He recommended heavier weight in my 5.0. Now I run Shell Rotella 15-40 T in my 302 crate motor and IT LOVES IT!!! It did NOT decrese oil consumption compared to 10-30 GTX, but my compression and valve seals are good however my intake is covered in oil and my PCV is looking more and more like hte culpret...when i swap out EFI to carb, i will re-do the PCV setup and remove it from the lifter valley, should solve te 1qt per 12-1600 mile loss.

No leaks and perfect compression and plugs are good exept 1 side of each plug is a bit fowled, indicating contaminants in the intake (assuming good valve seals) and last time i took the intake tube off and snaked something in there it came back dripping...same when I removed a plug in the intake to chance a vacuum line...ugly.

 

By loves it, i mean it runs cooler and with less sewing maching tapping from my cam.