LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Intake manifold oil leak symptoms..

Old 06-19-2009, 08:05 PM
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Default Intake manifold oil leak symptoms..

How bad can the intake manifold leak oil? I have a nice puddle under the car that forms after everytime i stop when driving the car. I eliminated a few things (oil pressure switch, oil filter, oil pan/rear main). I cannot think of anything else. I have oil everywhere under the car and also on the body (tranny tunnel area). Are these typical from leaking intake manifolds?
Old 06-19-2009, 08:46 PM
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Originally Posted by 1badzee
How bad can the intake manifold leak oil? I have a nice puddle under the car that forms after everytime i stop when driving the car. I eliminated a few things (oil pressure switch, oil filter, oil pan/rear main). I cannot think of anything else. I have oil everywhere under the car and also on the body (tranny tunnel area). Are these typical from leaking intake manifolds?
Given enough miles/years the heat from the egr tube breaks down the RTV that seals the back of the intake. So it is fairly common to get a leaky intake manifold.
Old 06-19-2009, 08:54 PM
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It was done last year.. and no EGR tube on this car
Old 06-19-2009, 09:02 PM
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Originally Posted by 1badzee
It was done last year.. and no EGR tube on this car
Then if it is in fact leaking from the intake manifold, it's because of installation error.
Old 06-19-2009, 09:03 PM
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Originally Posted by ss.slp.ls1
Then if it is in fact leaking from the intake manifold, it's because of installation error.

That's what I don't know -_- That's why I posted the thread lol
Old 06-19-2009, 09:38 PM
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when I put my hand under where the EGR is, I feel a THICK RTV silion LOL, I feel thanks to the last owner lol.
Old 06-19-2009, 10:00 PM
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yes, a leaky intake manifold can leaks tons of oil. If everything else checks out fine like you said, that pretty much just leaves the intake
Old 06-19-2009, 10:03 PM
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Originally Posted by Badazz 97 TA
yes, a leaky intake manifold can leaks tons of oil. If everything else checks out fine like you said, that pretty much just leaves the intake
Yeah, I just don't see how the oil would get on the body (above the transmission) if it weren't the intake manifold lol
Old 06-20-2009, 01:05 AM
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Originally Posted by ss.slp.ls1
Given enough miles/years the heat from the egr tube breaks down the RTV that seals the back of the intake. So it is fairly common to get a leaky intake manifold.
Bunch of crap. Hopefully you didn't get that bit of knowledge from Ken Collings since he knows about as much on that subject as a cup of dirt.
The EGR tube does not "break down" sealant. The reason why LT1 manifolds leak is either not enough sealant on the intake, dirty/sloppy install or the expansion/contraction of the entire intake (not just the area where the EGR tube is) causing intake bolts to loosen as well as sealant to fatigue over time or all of the above.
Hopefully you will not encourage the OP to wrap the EGR tube...
Originally Posted by 1badzee
Yeah, I just don't see how the oil would get on the body (above the transmission) if it weren't the intake manifold lol
Oil can get anywhere it wants. You must understand while the car is in motion the undercarriage is an extremely hostile environment.
Old 06-20-2009, 06:21 AM
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Originally Posted by SS RRR
Oil can get anywhere it wants. You must understand while the car is in motion the undercarriage is an extremely hostile environment.
Tell me about it.. It looks like a murder scene under there
Old 06-20-2009, 08:11 AM
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i had a leak from the back of my intake because of me and how stupid i was with the RTV silicone it wasnt enough
Old 06-20-2009, 09:03 AM
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My old LT1 was very leaky, when the motor was pulled.. pretty much all the way around the intake manifold was oil, and it looked to be like it was coming from the back of the manifold and dripping down from there to the ground.
Old 06-20-2009, 09:22 AM
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I had a bad intake manifold leak once, everytime I'd drive the car oil would pour on onto the exhaust practically and there'd be a cloud of smoke coming from under the car
Old 06-28-2009, 04:37 PM
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Originally Posted by myltwon
I had a bad intake manifold leak once, everytime I'd drive the car oil would pour on onto the exhaust practically and there'd be a cloud of smoke coming from under the car
Exactly what would happen. Anyway,

I replaced the intake manifold and put on VERY generous bead of Copper RTV on both sides of the block, and alas... IT STLL LEAKS lol. The intake manifold doesn't leak for sure (front is dry and i felt the back on the seam and it's dry). The oil leak seems to have gotten smaller (smaller puddles) so I assume the intake mani was just one of many leaks. Where else could the damn thing be leaking that much from? Under hard acceleration, my friend noticed that the car smokes (from oil hitting the exahust). HALP!
Old 06-28-2009, 05:01 PM
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Water pump drive seal or timing cover gasket maybe? That's where my oil leak is coming from. And everything under the car is just caked with oil. It gets on my x-pipe all the time and smokes also.
Old 06-28-2009, 05:11 PM
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Originally Posted by tspence45
Water pump drive seal or timing cover gasket maybe? That's where my oil leak is coming from. And everything under the car is just caked with oil. It gets on my x-pipe all the time and smokes also.
Nah, front of the motor/under it is spotless. Oil leak has to be coming from somewhere in the back/top. No leaks anyways up front or middle \=
Old 06-28-2009, 05:19 PM
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backs of the heads!

I had a 97 Z28 and someone had tried to mill the gasket surface on the side of my heads that meets the block. They ended up leaving huge grooves in it and the gaskets never set.......I had a shop do a dye test because I had already fixed my rear main, intake manifold, timing cover, valve covers, WP drive, oil pan, and oil sending unit...still leaked after all that... They put a dye in my oil and ran it for a bit then put the car on a lift...

They used a blacklight and shined it under my car and the dye glows flourescent in the blacklight. Any fresh oil was glowing and it led them to the back of my heads...both of them...and it was a BAD leak...I thought they only dealt with coolant in the heads, but apparently the oil can leak from the back...
Old 06-28-2009, 05:21 PM
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Originally Posted by Z28Camaro30Ann
backs of the heads!

I had a 97 Z28 and someone had tried to mill the gasket surface on the side of my heads that meets the block. They ended up leaving huge grooves in it and the gaskets never set.......I had a shop do a dye test because I had already fixed my rear main, intake manifold, timing cover, valve covers, WP drive, oil pan, and oil sending unit...still leaked after all that... They put a dye in my oil and ran it for a bit then put the car on a lift...

They used a blacklight and shined it under my car and the dye glows flourescent in the blacklight. Any fresh oil was glowing and it led them to the back of my heads...both of them...and it was a BAD leak...I thought they only dealt with coolant in the heads, but apparently the oil can leak from the back...
I have brand new DART heads with under 1,000 miles on them. That makes sense (what you're saying) but I would say that's quite a stretch for my situation. Thanks for the suggestion though!
Old 06-28-2009, 05:26 PM
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NP. I just remembered going through that situation before and it took me forever to get it down but that ended up being the problem.

Are you positive they seated right when they were put on? Did the leak start before or after the install? did you have the seating surface milled before you put them on, or did you just take em out the box and install them??

Not trying to insult you, just trying to cover all possibilities
Old 06-28-2009, 05:47 PM
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don't forget about the valve covers. I recently discovered my passenger side was leaking near the back of the head and I thought it was the intake.

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