'93 Corvette Oil Recomendations

[Craig]

In a week I'll be the proud owner of a '93 Vette convertable with the LS1 300 hp engine. 59K, extremely clean and I believe used Mobil 1 in it's life, probably 5W-30. Upon returning to Michigan from Milwaukee where I'm buying the car then driving home I will change the entire drivetrain to synthetic. I will probably go to Amsoil S2K 0W-30 for the engine. What recomendations do you folks have for the tranny (auto) and rear end? Not sure if it's posi but I think so. Thanks, Craig

 

[Patman]

I would recommend using Amsoil 5w40 instead of 0w30 in your Corvette. GM V8s like a slightly thicker oil. By the way, the 93 Corvette came with the 300hp LT1 engine, the LS1 didn't come out until 1997 in the Corvette (and in 98 in the Camaro/Firebird) Congrats on the purchase, and don't forget to wave to other Corvette owners! (I've got a 98 Corvette and always wave to every Corvette I see)

 

[Craig]

Thanks Patman, Your correct of course LT1. This is my second Corvette as I had a '63 (10 years old) when I was a kid. This is a decade year for me so I actually went to get a new C6 coupe but after pricing and realizing the tax consequences and the following chest pain I started searching the Corvette forums and found this beauty polo green/tan conv top for a decent price. Going to Milwaukee this next weekend to pick it up. Haven't been this excited for a long time. I will use the European blend as you suggest. I assume this is what you use? What OCI's do you do? I will probably go every 6 months regardless of milage. Probably also go to Amsoil ATF and some Amsoil S2K 75-90 gear lube for the rear end. Thank you again for your advice. Craig

 

[Craig]

Oh yes I will wave to all Corvette's on the road. Craig

 

[DJ]

Those who actually do analysis like Patman there will tell you the 5w-30 M1 everyone believes is wonderblood for the LT1 is not. Patman has owned an LT1 or two and done numberous analyses. Though yeah GM called for M1 5w-30 when new it was not a great choice then and today you would not be getting the same oil anyway so that recommendation is pointless. Watch it with synthetics in that tranny some work well like Amsoil others like M1 do not. My cars are mid 90s b-bodies(a Caprice and a Roadmaster wagon, the Impala SS falls in this catagory as well) with the LT1 and pretty much the same tranny and those on the b-body forums have done a lot of trial and error on this our much heavier cars stress the tranny more. Been through two tranny rebuilds myself, the second time I found a good shop and it is lasting with a lot more than your 300hp. Was running Mobil dino ATF now running Specialty Formulations a board sponsor here. Had the M1 ATF in the first rebuild and that all went badly and I am not the only one to have bad results with this fluid in THIS tranny, I do push it harder than most though.

 

[Patman]

Craig, I actually use German Castrol 0w30 in my LS1, but if it were not available my second choice would most likely be Amsoil 5w40. LT1s and LS1s both seem to like an oil that is close to the 12-14 cst at 100c range. So Amsoil's 5w40 is a much better match for the LT1 than their 5w30, which has recently been reformulated and is closer to 10.5 to 11 cst at 100c now. I have been slowly increasing my oil change intervals lately. When I first got this Corvette in August 2004, I went with a 5k interval. Then 6k, then 8k and my last interval was 9k. Every analysis has come back showing me a strong TBN and very low engine wear. Even after 9k the TBN was still over 5! So I have no concerns about doing 6 month intervals with my oil changes (which puts my mileage in the 8-10k range) Enjoy that Corvette, that is one fantastic color combo you're getting too! Polo green/tan should be offered on the C6 IMHO, I was not happy when they discontinued Fairway Green from the C5 lineup after only two years. That was my favorite C5 color. (my C5 is black, which looks awesome when it's clean but it doesn't stay clean for very long, it shows every speck of dust)

 

[Craig]

Patman, I also know black. I almost bought a new '93 Anniversary C4 but bought a all black '93 GMC Typhoon instead. So 13 years later I'm finally getting the C4. I think I'll wait to see how the new 6 speed auto does in the C6 and get one after it has a few years to get the bugs out (if any) I assume that you use the "green" special elves formula Castrol. As you are the German Castrol guru in that forum. I will consider Castrol also if the new gold is as good as the green. Thanks, Craig

 

[Mr Nice]

Even if the original owner didn't use Mobil 1, the inside of that engine should be very clean with such low miles.

 

[olefam]

GM called for Mobil 1 in a 5w-30 weight for my '91 coupe. That's what I've been using pretty successfully so far. Mine has the auto trans and it was changed over to synthetic ATF last summer before a long trip. Worked great! Diff is also Mobil 1 full syn and again, no problems. Enjoy the Vette. Glen

 

[Patman]

Yep, I use the green formula, I've still got a 2 year supply of it. My plan is also to get a used C6 someday, although probably not for another ten years or so. When I do get one it'll definitely be a 2006 or newer though, as I really like the idea of the A6 trans.

 

[Mr Nice]

Patman, You don't like shifting a 6 speed trans ??

 

[Racerjk]

M1 Ow40 feels great in my LT1.

 

[Patman]

LT4 Vette: I had a 6 speed in my 98 Formula and after 2 1/2 years of ownership the main reason I got rid of that car was because I was tired of the 6 speed. The nail in the coffin was when I mis shifted at the track two times in a row and ended up destroying my rear end in the process (the shock of the misshifts broke some teeth on the gears) I really do enjoy the automatic a lot more, especially with all the rush hour driving I do.

 

[Craig]

Patman, Doing some thinking about your recomendation regarding a thicker oil in my new '93 LT1. As I had some in hand I put in some HDD S3K 5W-30 with a new EaO filter. I believe my stock of HDD is SL. What are your thougts, would this be as good as the 5W-40? Thanks, Craig

 

[Patman]

Craig, IIRC that oil is a thicker 30wt, almost a 40wt, so it should work out well in the LT1.