Oil leak - Intake gasket
Thread Starter
Intermediate
Joined: Oct 2003
Posts: 35
Likes: 0
From: Columbia MO
Oil leak - Intake gasket
Hi, all. I'm new to the forum but a long time C4 owner/enthusiast.
My black/black '89 Coupe with just over 35,000 miles is at the dealership today for a new alternator (I tried to do the job myself but gave up when I couldn't loosen the battery lead connection. . .). While there, I had them try to find the source of a slight oil leak which had developed within the last year. I'm being told that the leak is coming from my "intake gasket" and that to replace it will involve over $700 labor/parts. Two questions for anyone who may know:
1) What "intake gasket" (location in engine) would leak engine oil? (I had my intake manifold gasket replaced a few years ago, when it started to leak COOLANT).
2) So far this is a slow leak; I changed the Mobil 1/filter last spring and the dipstick still shows just barely under the "full" mark. Will I be harming anything to let this go, and just keep a close eye on the oil level as I drive?
Thanks for any info out there on this.
My black/black '89 Coupe with just over 35,000 miles is at the dealership today for a new alternator (I tried to do the job myself but gave up when I couldn't loosen the battery lead connection. . .). While there, I had them try to find the source of a slight oil leak which had developed within the last year. I'm being told that the leak is coming from my "intake gasket" and that to replace it will involve over $700 labor/parts. Two questions for anyone who may know:
1) What "intake gasket" (location in engine) would leak engine oil? (I had my intake manifold gasket replaced a few years ago, when it started to leak COOLANT).
2) So far this is a slow leak; I changed the Mobil 1/filter last spring and the dipstick still shows just barely under the "full" mark. Will I be harming anything to let this go, and just keep a close eye on the oil level as I drive?
Thanks for any info out there on this.
Team Owner
Joined: Mar 2000
Posts: 83,384
Likes: 88
From: Boston, MA
Re: Oil leak - Intake gasket (gregcm)
Ugh I've had an alternator spin the bolt inside of itself so that I couldn't get the lead off either. I had to cut it and put a new end on it.
Anyways...
1) It is probably the same gasket. Did they say exactly where it is coming from? If it is the back of the block then it may be that when you replaced the gasket the first time the china walls of the block to the manifold didn't quite seal right. This is a common thing that happens if you do not use enough RTV there or if you use the cork gaskets and they bind or move during install.
2) If you've been driving it since spring and the oil level has hardly moved then it sounds perfectly fine to leave it alone. About how many miles have you put on the car? Some oil consumption is to be expected so they'll nearly never show "full" come oilchange time 3000 miles down the road. :)
The parts are probably $15 bucks and the rest is all labor. :(
p.s.
Welcome to the madness. :reddevil
[Modified by scorp508, 2:31 PM 11/6/2003]
Anyways...
1) It is probably the same gasket. Did they say exactly where it is coming from? If it is the back of the block then it may be that when you replaced the gasket the first time the china walls of the block to the manifold didn't quite seal right. This is a common thing that happens if you do not use enough RTV there or if you use the cork gaskets and they bind or move during install.
2) If you've been driving it since spring and the oil level has hardly moved then it sounds perfectly fine to leave it alone. About how many miles have you put on the car? Some oil consumption is to be expected so they'll nearly never show "full" come oilchange time 3000 miles down the road. :)
The parts are probably $15 bucks and the rest is all labor. :(
p.s.
Welcome to the madness. :reddevil
[Modified by scorp508, 2:31 PM 11/6/2003]
Instructor
Joined: Oct 2002
Posts: 103
Likes: 0
From: Smithfield VA
Re: Oil leak - Intake gasket (gregcm)
I replaced my intake manifold gasket earlier this year due to an oil leak. The leak itself was not that bad, but dripped on the exhaust manifold and stunk. Everywhere I checked wanted about $500 dollars to do it. It really is not that bad... just takes some time. What end up leaking is where the intake manifold seals to the block. In the front and back, the seal is made by RTV alone, no gasket. Wipe your hand along the back of the block behind where the intake manifold mates to the block. If your hand gets oily, then there is your problem. If you email me at skip_gina@yahoo.com, I can send you a document I received that goes through the process step by step. It took me about two days and I really took my time.
Skip
Skip
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Oil leak - Intake gasket (gregcm)
One thing to watch out for,sometimes the distributor gasket itself leaks oil and they still tell you ya need a $700++ intake manifold job.A very small oil leak from the intake either front or back usually isnt a problem if its not getting everywhere and dripping out all over.Almost all chevy engines leak here and usually the repair isnt done correctly the first time around.
But dont get taken by anyone for this job if you feel it needs to be done that bad.Keeping asking here and around for advise.
:)
But dont get taken by anyone for this job if you feel it needs to be done that bad.Keeping asking here and around for advise.
:)
Team Owner
Joined: Nov 1999
Posts: 26,679
Likes: 17
From: This vette goes to 11 Milford MA
St. Jude Donor '03-'05
Re: Oil leak - Intake gasket (gregcm)
The intake gaskets seal the manifold to the heads. You have coolant flowing between them and oil is splashed up by the lifters, so you could have it leak antifreeze or oil. All L98's eventually leak usually at around 10 years or 100k.
The factory runners are a pain to get off but overall its not a horrible job. It will take an afternoon if you've never done it.
The factory runners are a pain to get off but overall its not a horrible job. It will take an afternoon if you've never done it.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Oil leak - Intake gasket (gregcm)
This is a very time consuming job. As Scorp said, parts are cheap, labor is the killer.
If you're not at all familiar with your intake, then I'd leave it to a professional.
If you're not at all familiar with your intake, then I'd leave it to a professional.
