Misfits

my 97 lt1 jus hit 100,000kms today.. i've been using 5w30 mobile 1 for the last 50,000kms.. should i change it to sumthing different now?

user 647483

Keep using what you are using.

96capricemgr

A few of us have posted info that will allow you to make a truely educated decision, do a search and you will find it.
A good rule is that those who spout "Mobil 1 5w-30 is best" don't have a friggin clue, not that it is bad either. Do the search follow the links to the oil forum and learn something rather than listening to the completely baseless answers you will be flooded with here.

Misfits

ok jus searched a bunch of those threads and how i see it.. i must go to a thicker non synthetic oil after 110,000-120,000kms to avoid leaks from the seals...

Joe B

No offence, but thats about the worst thing you could ever do reguarding an oil change for a highmileage motor.. you might as well pull your CD player out and put an 8 track in it at the same time J/K .....read some more of the posts about it......Number one, the film strength with regular mineral based oil is NO where near what even some of the worst synthetic oils is, "no less" a proven to be great oil like what your using.......if you have leaks with your current 5W 30 mobil 1 (pretty thin) synthetic oil, then the smart thing to do would be to either fix the seals that leak, or if you have small leaks that you don't want to pay to get fixed at this time, you could just go to a higher weight synthetic oil to help this a little.... this way you still have the high quality oil with a good film strength reguardless of the oil's weight.......anyone that tells you that there's a good reason to go back to old style mineral based oil really knows nothing about oil's and their filmstrength.....point being stay with what your using, or like I mentioned, if you have some small leaks, try some heavier weight mobil one(still fully synthetic)..........

Misfits

i have absolutely no leaks anywhere on my car.. yea i've also been told what u jus said (use the 10w 30 instead of 5w30)

so i'll jus switch my oil weight, thanks and stick with the mobil 1

96capricemgr

You must not have learned anything from the search I told you to do. At operating temps where it matters 10w-30 may or MAY NOT be thicker than 5w-30. Anyone who tells you otherwise does not know what they are talking about some of the thickest _w-30 oils we will recommend are 0w-30, M1 10w-30 sometimes even being measured as thinner than the 5w-30. Not that viscosity is the beall endall of oil selection either.

Robs97Z28

5W30 and 10W30 ARE THE SAME OIL AT OPERATING TEMPS. They are both 30w oils!!! 5w and 10w have to do with cold temps!!! If you want to change the oil vis go to mobils' 0W40!!!

Also, go to www.bobistheoilguy.com

HardcoreRM125

I might sound arrogant, but I would never switch from Mobil 1, or at least not on the stock short block.

Bret has torn down hundreds of LT1's for performance rebuilds, and has, on more than one occasion, stated that the M1 motors had significantly better bearing condition and such when compared to Redline, Royal Purple, etc. Castrol Syntec 0W30 is impossible to get around my way (Ive checked EVERYWHERE), other wise I would run it ...

Basically, if you cant get German Made castrol syntec 0W30, then go with M1 5W30. If you have too low of oil pressure using 5W30, SOME people on here have reported getting a higher pressure at operating temps when they used M1 10W30. While they are both 30 weights, the 10W30, for some reason, has shown higher operating temp. oil pressure. So give it a try. Then there is always 0W40 M1, but that is hard to find around here too ... I would probably, in all honesty, just run a 5W30 though inless you have oil pressure complications. Look for at least 20 PSI at hot idle.

Z28SORR

Bottom line on all this is simple, don't change your oil type/weight unless you have a compelling reason to do so.
Some good reasons would be, a change in location, to one that is extremely hot or extremely cold. Evidence of bearing wear, or slight loss of oil pressure, but not enough to require a rebuild. Pushing your engine, like drag racing or road racing.
I would never consider oil leaks as a compelling reason to change my oil type. If you have leaks you should fix them. For years I've used Kendel 20-50 oil in my race engines, they still leaked!
Because the people on this board are enthusiast they are always looking for the "best". But the fact is that even for the occational drag racer there are few good reasons to change from the factory recommended oil.