redvette1985

I know this has probably been answered before but I am new and have not quite gotten the hang of the search part.

I have a 1985 corvette that has an oil leak I can't seem to find. I have replaced the distributor seal, oil pan seal, and valve cover seals.

I had an issue with an oil filter that was replaced because it would not seal. when I turned the car on I could see oil coming from around the seal of the filter. it was on tight. I replaced the filter and it does not seem to be leaking from the filter anymore. after driving the car foe about 15 min I park it in my driveway and I can see oil drip about 4 or 6 in in front of the oil filter. there is no oil on the filter so i know that is not the problem anymore. there is also spray back on the transmission pan. I have not replaced the rear main seal or oil pressure sending unit. that was my next step. I really don't want to pay $$$ to have the rear main seal fixed. the oil is only about the size of a half dollar. is there anything else that you can think of to fix the leak?

I have looked up the sending unit and have found two different units for the 1985. can someone please post a link for the correct one so i can try to replace that before i do the rear main seal. Are there any other seals that i should replace? is there anything else I should have done if I have to replace the rear main seal.

the car sat for 2 years prior to me getting it but it runs great except for the small oil leak.

thanks in advance,
Nate

Cruisinfanatic

I think you should have the leak diagnosed instead of throwing money at parts you don't need

redvette1985

I have taken it into the shop 3 times for the leak and those are the only 2 times that have not been replaced. I was told he looked at the rear main seal and it did not look bad. He can't seem to find the source of the leak.

Mose1

Rear intake manifold leak? Leaking at china wall, and running down back of motor is a possibility . Seems to be a common issue on these L98's..

DinoBob

Exactly what I was about to post. Also, does this car have an oil cooler? Could that be leaking? You should see two coolant lines running to the oil filter housing if so.

QCVette

That is what I was going to post.

On my '85 the oil cooler lines were leaking. They attach just above the oil filter. On mine the oil would run down the line and drip a few inches in front of the oil filter.

It is at least worth checking.

I agree with Cruisinfanatic to find the problem before throwing parts at it.

Good luck.

redvette1985

I don't have the oil cooler on my car. I will look at the manifold and rear main seal to see if I can find the leak.

corvetteronw

This pic shows the rear china wall with The Right Stuff on it. Dimple the china wall and the portion of the intake manifold that it mates to also.
Make sure the oil pressure sender that you can see in the pic is not leaking also.

WW7

If you use a mirror with an extension you can see behind the manifold on both sides if you get the wires out of the way..If that won't work remove the distributor so you can see behind the manifold....If it's wet behind the manifold then it's most likely leaking at the China wall......WW

3JsVette

Suggestion. Clean the engine real good. Add florescent dye to the oil. Drive the car. Then use a black light to inspect for leaks. The source of the leak will light up bright yellow from the dye. It's the same principle as looking for a refrigerant leak in the A/C system. In the long run it should be able to stop you from throwing more parts and labor at it with no appreciable results.

Tom400CFI

There you go. This is the KEY, to finding oil leaks. Clean first (b/c if it's been leaking a while, there is oil "everywhere"), then observe. Take to a self serve car was and use the 'power washer" want. Get it clean, under, over, sides...clean it. Dye helps, but not necessary.

redvette1985

I just had it looked at and the issue seems to be the rear of the intake. It's a $350 job to get the seals replaced. My question is if he has to take the top of the engine off is there anything else that could be done for performance or prevention issues. It's in the shop now and work will start tomorrow so I need opinions asap.
Thanks in advanve