69mako

94 Corvette coupe with the LT-1 motor and auto trans I have 110,000 miles on it. I now have an oil leak on the back driver's side of the block.....starting to seep on to the converter :eek: :eek:

What is the cause and how easy is it to fix.

I think the back seal on the intake manifold is starting to go :yesnod:

Any help would be nice, Thanks. Larry :cool:

93 ragtop

The LT1 is bad for that. When you pull the intake to fix it, make sure the surfaces are very clean, and let the sealer dry 24 hrs before starting the engine.

atotalnincompoop

:iagree:

69mako

Or could I get lucky and have the oil coming from the oil pressure sensor????
I now have the back of the block cleaned off...a little greased lighting is fantastic for cleaning motors :yesnod: :yesnod:

I will keep an eye on it for the next few days.

If it is coming from the back of the intake...where should I look...in the corners....or right on the seating serface itself?

oldace84

Can only think of it being the intake manifold...have you done any work back there?????
Any back pressure in the motor that would cause the intake manifold to blow out..or has it been leaking a little at a time..until now????
tony
:smash:


[Modified by oldace84, 5:31 PM 12/16/2002]

MinnesotaWhite

Horrendously common on the LT1...don't sweat it...just replace the gasket.

69mako

I see the oil starting to leak right in the back of the intake manifold :thumbs: ...Well; there is a project right after I get back from vacation. No biggie :lol: :lol:

Thanks for the help guys :thumbs: :cheers: :thumbs:
Larry. :cool:

Joeyvette

No big deal ;) Just had mine done last month with 54,000 on the clock. :thumbs:

Corvette0096

Get some of that stuff in a can called "The right stuff"

chucks88

:yesnod: :iagree: :yesnod:

69mako

C :cool: :cool: L thanks, Larry :steering:

lcvette

69 mako, its a 45 minute job, fuel rail bolts, fuel rail cover pin bolts, unclip wiring harnesses from sensors and injectors, alternator bracket bolted to manifold, disconnect negative battery cable, and remove manifold bolts. scrape front and rear block surfaces and clean with clean rag and non residue leaving cleaner degreaser, remove manifold gaskets and remove and glue if any is aparant, clean manifold mating surfaces. replace new manifold gaskets, and lay a 3/8" bead of silicon gasket maker, i am partial to RTV copper gasket sealer (adheres very well) and here is the trick allow to set for 10 minutes before mating the manifold to the block, this will allow the sealant to ligfhtly skin over. also when setting the manifold down, be careful to align the manifold holes with the holes in the heads, any forward or rearward movement when touching the sealant will require removal and recleaning of both surfaces. trust me they don't seal for long if you slide them around. also run the bead of RTV about 1/2"-2/3" up the manifold gasket end. this will ensure a good seal. if the plastic locators on the intake gaskets reak upon removal, a trick to get them out is to take a self tapping screw smaller then the hole and a phillips screw driver and screw the self tapping screw into the center of the plastic locator, it will come out with a little tug after the threads have gone in a turn or two... just a small trick i learned along the way. good luck with it! its really fairly simple and straight forward!

Chris

Thud

I've gotta do this job too... I've been putting it off since I bought the car over 2 years ago, and I've had the new gaskets lying around all this time. :bb Mine's leaking from the front and rear!
But since I'm on vacation all next week, that would be a perfect opportunity.

I used to have a hardcopy of a GM TSB which has a recommended part no. for replacement sealant-- anybody know what it is, or is that copper stuff from Pep Boys just as good?

fullboogie

lcvette is right on - that's exactly how to fix it. Use RTV Copper or Ultra Black. By the way, mine's doing the same thing with only 10k on the engine! :cry

Springer's LT4

Also check the oil filter adapter housing gasket... my intake was leaking, but no wheres as bad as the adapter housing gasket.

Alex D

Yeah...old LT1/4 problem.....all LT cars get this leak......I once read that two reasons were the cause for the engines being leak prone. one was a problem with degreasing and cleaning the mating surfaces and the other was that a better sealant was needed and found later on. There is a TSB that lists the new RTV with OEM number. I have also heard that this new original RTV is by far better than all aftermarket RTVs and that its use is highly recommended to seal the intake permanently.........my 96 LT4 leaked in the back after only 9,500 mls., my current 96 LT1 with 24,000 miles is still dry as a bone and has no loil leaks whatsoever...lucky dog :yesnod:

Shaun Patrick

I got a '94 LT1 that had the same problem. It turns out that there was a bad intake manifold gasket. In my case, the oil was only visible on the block, it hadn't dripped on the ground. I had it replaced by an ASE certified GM dealer and it cost around $330. It sounds like this could be your problem too. Hopefully it's nothing worse. Hope this helps. Merry Christmas.

69mako

UPDATE: The oil is coming off the back of the block where the intake meets the block... the gasket goo is slipping out and I can see the oil starting to slide out a tiny bit.

I must have had this problem start over the summer.

I will be replacing the gaskets myself with the help of 96LT4 after the holidays have passed :thumbs: This is nothing new to me...I have replaced the gaskets on my 72 twice.....and helped others do the same.....
I'm not about to give some my $$$ to someone esle, when I can do it myself for the cost of the new gasket set and a tube of goo :lol: :lol: :lol: :lol:
Larry :steering: