Leaking Oil - Any ideas
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 7,163
Likes: 61
From: NH
St. Jude Donor '14
Leaking Oil - Any ideas
Hi guys,
My 91' L98 is leaking oil. It leaks from the driverside, above the filter / headgasket, but below the valve cover. Does anyone have any ideas about what between there may be leaking? Its not a huge leak, and my mechanic could see the path and got that far but couldn't identify it without going in-depth (had him doing a quick 02 sensor replacement). Was curious if anyone had any ideas?
(PS - Accidentally posted this is another forum (gen discussion) - someone said intake or oil pressure sending unit. Where should I look to figure out which?
Thanks,
Joe
My 91' L98 is leaking oil. It leaks from the driverside, above the filter / headgasket, but below the valve cover. Does anyone have any ideas about what between there may be leaking? Its not a huge leak, and my mechanic could see the path and got that far but couldn't identify it without going in-depth (had him doing a quick 02 sensor replacement). Was curious if anyone had any ideas?
(PS - Accidentally posted this is another forum (gen discussion) - someone said intake or oil pressure sending unit. Where should I look to figure out which?
Thanks,
Joe
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Whomever suggested the intake or oil pressure sending unit is right on track.
You really need to get a dye, but the problem here is that both are right on top of each other.
How many miles on the car? Has the intake ever been serviced? Is there any sign of a coolant leak?
You really need to get a dye, but the problem here is that both are right on top of each other.
How many miles on the car? Has the intake ever been serviced? Is there any sign of a coolant leak?
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 7,163
Likes: 61
From: NH
St. Jude Donor '14
Originally Posted by bogus
Whomever suggested the intake or oil pressure sending unit is right on track.
You really need to get a dye, but the problem here is that both are right on top of each other.
How many miles on the car? Has the intake ever been serviced? Is there any sign of a coolant leak?
You really need to get a dye, but the problem here is that both are right on top of each other.
How many miles on the car? Has the intake ever been serviced? Is there any sign of a coolant leak?
Backround - The car overheated when the previous owner told me the fluids were all just changed, and I foolishly took his word and didn't check myself, only to overheat and blow my starter a week later due to low coolant.
Right now, since I see it on the block, I'm guessing its the intake manifold gasket. I'm going to grab my camera and see if I can get some decent pictures. I can see the joint where the oil is coming from, and its below what I believe is the intake manifold (new to DIY / SBC, so ya gatta cut me some slack).
Anyone want to recommend a nicer gasket I can pick up for when it gets fixed?
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
It's not the gaskets that leak... the SBC uses an RTV bead at the front and rear of the block. That's what wears out. The RTV will give up after a while.
A few suggestions for improving the RTV's live span:
1) Drill some small dimples into the block and intake so the RTV and grip better.
2) Using a scotchbrite pad, scuff up the block and intake.
3) someone suggested carefully machining in a groove to accept an o-ring type of thing. That would require removing the engine!
Use either GM or Fel-pro gaskets. And get the best highheat RTV you can find... I don't remember the RTV that GM recommends off hand.
You really need to get a copy of the Helms Manual - www.helminc.com - it will make these repairs soooo much easier.
Oh, this problem is not so much mileage dependant as it is time dependant. The RTV just looses its grip on reality.
A few suggestions for improving the RTV's live span:
1) Drill some small dimples into the block and intake so the RTV and grip better.
2) Using a scotchbrite pad, scuff up the block and intake.
3) someone suggested carefully machining in a groove to accept an o-ring type of thing. That would require removing the engine!
Use either GM or Fel-pro gaskets. And get the best highheat RTV you can find... I don't remember the RTV that GM recommends off hand.
You really need to get a copy of the Helms Manual - www.helminc.com - it will make these repairs soooo much easier.
Oh, this problem is not so much mileage dependant as it is time dependant. The RTV just looses its grip on reality.
