Which Oil?
Thread Starter
Advanced
Joined: Jan 2019
Posts: 83
Likes: 23
Which Oil?
Hi everyone, first post here. Here's the background: I purchased a 96 6 speed with the lt4 engine about a week ago. I believe it's in relatively good shape, but am trying to get a few things done before I start driving it regularly. Number one on that list is an oil change. The window sticker from its last service shows its only been about 1000 miles since the last change, however that was in 2016... so im planning on doing one now anyway.
The car has 74k on the odometer, and the dealer started there was a small oil leak somewhere that their mechanic couldn't locate immediately without further investigation. The car had no drips under it in the show room when i inspected it, and has not left any drips in my garage yet either, even after being driven and warmed up. The dipstick also shows full to the top of the hashmarks, so ive got to believe it's a pretty slow leak.
That's all the pertinent information I can think of right now, but I'll try and answer any questions anyone might have.
Should I do my oil change with 5w30 or 10w30? Every time I feel confident in my choice of one I seem to dig up some more info to support going with the other.
Thank you!!!
The car has 74k on the odometer, and the dealer started there was a small oil leak somewhere that their mechanic couldn't locate immediately without further investigation. The car had no drips under it in the show room when i inspected it, and has not left any drips in my garage yet either, even after being driven and warmed up. The dipstick also shows full to the top of the hashmarks, so ive got to believe it's a pretty slow leak.
That's all the pertinent information I can think of right now, but I'll try and answer any questions anyone might have.
Should I do my oil change with 5w30 or 10w30? Every time I feel confident in my choice of one I seem to dig up some more info to support going with the other.
Thank you!!!
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
I would use 5W-30 full synthetic oil. That is what GM put in 92 and later Corvette engines when they were new. The Owner's Manual will have a table that shows what viscosity to use based on conditions. As everyone knows, Mobil-1 oil was the factory fill but using a good full synthetic that meets the new Dex2 standard will work fine. Just make sure you see that logo on the oil bottles.
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Melting Slicks
Joined: May 2013
Posts: 2,692
Likes: 349
From: Sacramento California
In a moderate climate, 5w30 or 10w30 does not matter. Most use 5w30 just because it's the factory spec and has a slightly better flow at very low temperatures. Otherwise you will see zero difference and I also vote for 5w30. For oil filters, check www.rockauto.com for clearance sales. I got a bunch of Mobil 1 filters for about $2.75 apiece.
My 1995 LT1 also has a very slow oil leak -- the underside of the engine area has a light film on everything and it leaves 8-10 drips per year on the garage floor. It is so minor that I've decided not to pursue it. The dipstick always reads full, every single time.
Enjoy your new ride and welcome to Corvetteforum
My 1995 LT1 also has a very slow oil leak -- the underside of the engine area has a light film on everything and it leaves 8-10 drips per year on the garage floor. It is so minor that I've decided not to pursue it. The dipstick always reads full, every single time.
Enjoy your new ride and welcome to Corvetteforum
Advanced
Joined: Apr 2018
Posts: 63
Likes: 11
From: Inver Grove Heights MN
I have a 1996 LT4 also and the oil fill cap reads Mobil 1 synthetic 5W-30 only. I had an oil leak as well and to replace the intake gaskets. The leak was coming from the front of the engine where there is silicone across the front of the valley. Make sure you get LT4 intake gaskets if that's the cause due to the intake ports being much larger.
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,282
From: Hartford WI
Hi everyone, first post here. Here's the background: I purchased a 96 6 speed with the lt4 engine about a week ago. I believe it's in relatively good shape, but am trying to get a few things done before I start driving it regularly. Number one on that list is an oil change. The window sticker from its last service shows its only been about 1000 miles since the last change, however that was in 2016... so im planning on doing one now anyway.
The car has 74k on the odometer, and the dealer started there was a small oil leak somewhere that their mechanic couldn't locate immediately without further investigation. The car had no drips under it in the show room when i inspected it, and has not left any drips in my garage yet either, even after being driven and warmed up. The dipstick also shows full to the top of the hashmarks, so ive got to believe it's a pretty slow leak.
That's all the pertinent information I can think of right now, but I'll try and answer any questions anyone might have.
Should I do my oil change with 5w30 or 10w30? Every time I feel confident in my choice of one I seem to dig up some more info to support going with the other.
Thank you!!!
The car has 74k on the odometer, and the dealer started there was a small oil leak somewhere that their mechanic couldn't locate immediately without further investigation. The car had no drips under it in the show room when i inspected it, and has not left any drips in my garage yet either, even after being driven and warmed up. The dipstick also shows full to the top of the hashmarks, so ive got to believe it's a pretty slow leak.
That's all the pertinent information I can think of right now, but I'll try and answer any questions anyone might have.
Should I do my oil change with 5w30 or 10w30? Every time I feel confident in my choice of one I seem to dig up some more info to support going with the other.
Thank you!!!
I would not change oil right now. Dump some dye in it and clean the engine thoroughly and use a blacklight to locate that oil
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
same here and
- service all fluids, AND FILTERS, and establish a maintenance baseline. start with the oil, then cooling system, and work your way back. usually folks are pretty good when it comes to engine oil, but most neglect the cooling system, brakes, and maintenance of other fluids. some really don't require periodic "drain and fill," others do. for the tranny, steering, and differential, at a minimum, check the levels. it's 23 years old, it's new to you, with pretty much an unknown history. you very well could be running the original antifreeze - 
. (I know at least one 93 vert that's running the original coolant and fuel filter - 
) you don't have to do it all at once, but establish a check list. service one, and do it very well (in other words, be ****) - then move on. BTW, since it's most likely unknown, i'd also recommend a new fuel filter, and what the hell, might as well throw in a new air filter, and serpentine belt. when all that is done, then you can really relax! good luck with your new ride. enjoy - 
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,282
From: Hartford WI
If the trans fluid looks really fresh, I am wary. I have seen people drop the pan and put fresh fluid in but because they were selling the car, didn't want to bother with the filter. All to save a few bucks.
Team Owner
Joined: Sep 2001
Posts: 62,143
Likes: 1,729
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
If I do a lot of winter driving, 5w30. If I do mostly summer, 10w30. If I was racing, I'd consider other weights.
Buy a synthetic and don't worry further.
Buy a synthetic and don't worry further.