Swe_Daniel

Hey folks, a proud, and now sad vette owner checking in with a question...

Today I was out driving the vette in the suburbs of stockholm, really slow house shopping-cruising.... well the car was going pretty hot(as vettes do when you drive them slow in cities etc... not exeptionally hot, just normal for the circumstances.

then suddenly, after 5min on the highway(the engine was going down in temp, oil and water) crusing at a normal vette speed not hard driving at all, aprox 70-75mph there is a big smoke cloud behind the car. I start talking about about that it must be from some crappy bmw behind me.. then I realise that it is my car causing this!

I immidiatly stop and get down under the car to see what is going on, the transmission(automatic) looks coverd in oil and it is getting on the exhaust(which is causing the smoke) ok, i let it sit and cool down and wonder what is going on.. the oil looks like engine oil, not transmission oil... to get back home i start her up and she runs like nothing has happened, shifts perfect, engine sound like new(as it always have)

I drive really carefully home, and it seems like the oil leakage has stopped, but there was some smoke coming from everwhery cause of the prior leakage.

now I'm trying to figure out was could be causing this sudden oil leakage, have any of you guys had this happen to you? am I looking at an engine rebuild? the car has always ran strong and sounded like it was new, I just changed the oil as I do every 600kilometers..

The Green Hornet

Better check your oil level

bogus

well, I suspect you are possibly looking at a rebuild if it ran out of oil thanks to the leak.

I would love to see the engine right now, cause I have a short list of what could have failed:

1) Oil pan
2) rear main seal
3) oil filter cracked
4) oil filter housing
5) serious block failure (unlikely)
6) front main seal

or, finally, you ran over something unrelated and it covered your engine in oil.

I would raise the front end, spray it down with simple green (or a similar degreaser cleaner) and hose it clean. Then check for leaks.

I assume you checked the oil level? If not, that could be real bad...

What year?

You change the oil every 600 clicks? That's a huge waste, I hope you meant 6000 clicks!

Swe_Daniel

Thanks for your answer, I checked the oil level after it happened and it was fine, no sign of leakage there.

The car is a -94 and I dont change the oil every 600clicks, aprox 6000

I'm gonna hose it clean and check for leaks, I might be able to take som photos of it. rear main seal sounds possible, the engine looks totally dry, the only place there is oil is under the transmission.

changing the rear main seal is a pretty big operation right? disconnect the transmission etc.

perfect start of the summer

Pete K

I had the exact same thing happen once. The adapter under the filter(oil pressure relief valve) was cracke . Caused the filter to overpressurize and blow the oil out of the filter o ring. I did not find it till it was unbolted. Then the 2 pieces dropped down.

aminnich

Check you auto trans fluid level before you go cruising again. I think I read there is a overfill/pressure relief valve on top front that might have blown out some fluid. Better yet ask our A4 on line expert--PeteK, I may well be wrong.

Swe_Daniel

An update, I have been under the car and done some investigating.. and it doesn't look that bad.

I'm attaching some pictures that is showing the leakage, maybe you can help me identify what it is exactly. I realised after I got the car down that I should have tried fastening the bolts, that would have been worth a try right?









Finally, this is the car.. taken today.

bogus

you do have a leaking rear main seal.

But I don't understand how it would flush out oil, then stop.

I would go through some diags, check the oil filter housing like suggested above.

The rear main seal DOES require the removal of the transmission.

aminnich

Look at the very top center rear of the motor. I think what you are seeing is actually running down from the top and am thinking rear intake gasket is leaking. Probably has been for sometime, just a seep. All the slow driving you got more than normal leak so it was enough to burn off the exhaust and smoke.

Your pictures pretty much confim the above. What you are pointing to is the electric starting motor that bolts to the bellhousing. Neither one of those contain any oil. Another picture shows oil tracks on the bellhousing seeping down from a point higher on the motor.

Corvette Kid

The seal you pointed to is a gasket, more of a dust seal actually for the starter, not related to keeping any liquids in the engine. Many of the normal oil leak sources can appear to have the oil coming out of the bellhousing area. My guess is that you possibly blew out the rear intake seal (a silicone joint) when going down the highway. Have you had it up to highway speed since? This would explain all of the smoke too, when it occurred. It wouldn't really take much oil coming down onto the cats to look like real disaster behind the car. Another possibility would be either the oil sender or sensor located at the rear of the intake. Could be something as simple as a valve cover gasket too, but if it's coming down both sides, I doubt it.

Swe_Daniel

Thanks for the input!
Actually, as far as I could see, the leaking was only coming from the gadget that I was pointing at in the pictures, also if you look close at the pictures it looks like the sealing has been pushed to the side and is not centered.

What is this gadget that I'm pointing at in this picture? couldn't it bee just the sealing around it that has broken?

Corvette Kid

That's your starter you're pointing to. And as I already stated, the oil is not coming from there, it is only dripping off of there. It is coming from somewhere higher.

anesthes

Sure it's oil and not tranny fluid?

-- Joe

LS6 Motor

On my 91 L98, it was the intake mainifold gasket as mentioned above. When I took the top end down this winter to do the injectors, I also pulled the intake, and the silicone sealer was blown out on that side. My starter was covered with oil, along with the flywheel cover, and everything else. I took the liberty of pulling the starter, to clean, and rebuild, as the oil had been leaking for sometime, long before I purchased the car. This is a common occurance with these cars as they use no gasket at the front, or rear of the block. Hope this helps!!

tholm1

My 95 LT1 does the same exact leaking smoking scenario. I would check around the back of the intake manifold. The front and rear intake manifold seals on the LTX motor are just RTV silicon and fail regularly. However that much oil is not coming from the intake manifold, it probably coming from the rear main seal. My vette leaked out the intake manifold a while back and it didn't smoke like that. About 6 months ago I had my oil changed at a Sears Grand in Austin, TX and they forgot to take out the old oil before they put the new oil in. The way I found out about it was from all the smoke coming from under the car. I checked the oil to see if I was low from all the leaking and to my surprise I had 8 quarts of oil in my car. Sorry I'm probably not helping at all, but I had to vent.

I'm now trying to justify a complete 383 rebuild of the engine if I have to separate the tranny from the engine.

onedef92

I think it's your intake gasket. Also, check out your PS pump and hoses, especially the rack-to-resovoir pipe. Look at the lower cross member that runs near the rack for telltale fluid leaks, too.

JBB

As was stated by others, the part in question is your starter. The oil is likely coming from above the starter & dripping off of it. Chech the Rt side valve cover & the rear intake seal. When driving slow the exhaust isn't too hot, but cruising @ 70 the cat(s) would light off (normal)causing the smoke. Often an around town car will build up oil underneath & smoke like crazy when finally driven on highway. Wash down underneath & the bellhousing area. (Careful of any electronics, I don't know what year you have, some have a dist in back & others have an ECM on the LR.) After washing down & checking fluids, look for the source with a mirror & a good light.

lefoy84

On the engine block just aft of the intake manifold on the rear of the engine and to the left of the distributor is the oil pressure port. On my 86 there is a short nipple and a 90 fitting. Attached to this is the oil pess sender and a switch called the oil press fuel pump switch. This switch sprung an internal leak and pumped out above 3 qts of oil before you could drive 2 miles. Had to pull the engine to check for damage.

Swe_Daniel

Hi! a big thanks to everyone helping out!

Tonight I was trying to locate the leakage, trying to see anything at the back of the engine is a PITA

Anyway here are some pics of this evenings adventure, First a few with the engine as it was, then after trying to clean it up
a bit (I'm gonna to a totall engine clean up really soon) I started up the car for a short while but it didn't spit any oil,
that I could see..

I might have to take her for a drive for it to start leaking,
couldn't do that tonight cause we cracked a couple of beers while doing this













This is after cleaning a bit with some WD-40

LD85

My oil pressure send that attatches to the back of the intake blew and leaked a ton of oil out quickly, make sure that this does not ahppen because it will drain quickly.