Oil leak
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 8,271
Likes: 411
From: Mt. Sinai NY
Oil leak
Ho all
Just looking for some general info. I nave a friend who has a 1990 c4 and has an oil leak that seems to be coming from the middle of the car. He doesnt have access to a lift amd I was wondering if I could tap into the wealth of info here on the Forum. The car has 90,000 miles Thanks
Clif
Just looking for some general info. I nave a friend who has a 1990 c4 and has an oil leak that seems to be coming from the middle of the car. He doesnt have access to a lift amd I was wondering if I could tap into the wealth of info here on the Forum. The car has 90,000 miles Thanks
Clif
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
Ho all
Just looking for some general info. I nave a friend who has a 1990 c4 and has an oil leak that seems to be coming from the middle of the car. He doesnt have access to a lift amd I was wondering if I could tap into the wealth of info here on the Forum. The car has 90,000 miles Thanks
Clif
Just looking for some general info. I nave a friend who has a 1990 c4 and has an oil leak that seems to be coming from the middle of the car. He doesnt have access to a lift amd I was wondering if I could tap into the wealth of info here on the Forum. The car has 90,000 miles Thanks
Clif
on my 90, I had a major oil leak at the rear china wall. not an impossible job to fix, but it does take some effort to repair.
I'd start by cleaning everything the best you can, and try to pin point the leak. they do sell UV (light) leak detector - I've never used it on an oil system though....
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 8,271
Likes: 411
From: Mt. Sinai NY
could be anyplace. if it is engine oil, and not tranny fluid, check - valve covers, rear china wall, oil pressure sensors, oil pan, or front/rear main seal. need more info.
on my 90, I had a major oil leak at the rear china wall. not an impossible job to fix, but it does take some effort to repair.
I'd start by cleaning everything the best you can, and try to pin point the leak. they do sell UV (light) leak detector - I've never used it on an oil system though....
on my 90, I had a major oil leak at the rear china wall. not an impossible job to fix, but it does take some effort to repair.
I'd start by cleaning everything the best you can, and try to pin point the leak. they do sell UV (light) leak detector - I've never used it on an oil system though....
Thanks for your response. Its motor oil thats leaking. Im not familar with the term "china wall"but the general consensus is the rear main seal. Basically what Im looking for is info from c4 owners about common problems inherent with the car
Thanks
Clif
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
A leak from the valve covers, back of the intake manifold, rear seal will often look like it's coming from the rear of the engine. The repair will range from simple to major (engine out.) The only way is to clean the area, as Joe suggested, and see exactly where new oil is leaking from.
Last edited by 383vett; Jul 29, 2016 at 10:29 AM.
Racer
Joined: May 2013
Posts: 405
Likes: 15
From: Panama City Beach Florida
Most likely the rear of intake manifold
That's where my 94 leaked, in the center at the back of engine. The front and rear of the intake manifold are RTV'd and called the china wall because of the pattern of the intake at the front and rear. (like the great wall of china)!
Race Director
Joined: Aug 2000
Posts: 11,470
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"common problem inherent to a 90" - nothing more inherent than any other SBC. - I've had two 90's. my first 90 was bone dry - zero leaks - never had leak issues. my current 90 had a major leak at the rear china wall when I bought it, mostly due to a poor mechanical repair during, i'm thinking, a head gasket repair. long story short, corrected the problem, and today, bone dry and zero leaks. as long as the gasket and seals are of good quality, with proper mechanical repairs, L98's and 90's in general are like any other small block, there are no inherent leaking issues. I have found that most oil leaks are due to poor mechanical skills by "wrench benders."
Last edited by Joe C; Jul 29, 2016 at 01:39 PM.
Advanced
Joined: Jul 2013
Posts: 87
Likes: 13
From: Tampa Bay area Florida
I had a rear crank seal oil leak in my 98 TA. Used some of this and it cleared it up for about a year so far.
http://store.gobdp.com/rear-main-sealer-00234/
http://store.gobdp.com/rear-main-sealer-00234/
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Burning Brakes
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Cruise-In II Veteran
As a very long time owner of a 1990, I have seen just about everything. On my own car and other owners.
The two most common leak points on a L-98 engine are the aforementioned intake manifold "China Wall" and the oil pressure sensors that are located at the rear of the block.
My suggestion is that after a good clean-up of the block, put some UV (ultraviolet) dye in the oil. Kits to do this are available at Autozone, O'Reilly's, etc. They include the dye, a UV light and special goggles for viewing.
With the UV dye you should be able to spot the leak point very quickly.
The two most common leak points on a L-98 engine are the aforementioned intake manifold "China Wall" and the oil pressure sensors that are located at the rear of the block.
My suggestion is that after a good clean-up of the block, put some UV (ultraviolet) dye in the oil. Kits to do this are available at Autozone, O'Reilly's, etc. They include the dye, a UV light and special goggles for viewing.
With the UV dye you should be able to spot the leak point very quickly.
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 8,271
Likes: 411
From: Mt. Sinai NY
As a very long time owner of a 1990, I have seen just about everything. On my own car and other owners.
The two most common leak points on a L-98 engine are the aforementioned intake manifold "China Wall" and the oil pressure sensors that are located at the rear of the block.
My suggestion is that after a good clean-up of the block, put some UV (ultraviolet) dye in the oil. Kits to do this are available at Autozone, O'Reilly's, etc. They include the dye, a UV light and special goggles for viewing.
With the UV dye you should be able to spot the leak point very quickly.
The two most common leak points on a L-98 engine are the aforementioned intake manifold "China Wall" and the oil pressure sensors that are located at the rear of the block.
My suggestion is that after a good clean-up of the block, put some UV (ultraviolet) dye in the oil. Kits to do this are available at Autozone, O'Reilly's, etc. They include the dye, a UV light and special goggles for viewing.
With the UV dye you should be able to spot the leak point very quickly.
Clif