When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have an oil leak in the rear of my LT1, on the driver’s side. It is dripping down on the exhaust pipe, and generating smoke. It is puddling on the rear of the block. I can see the shiny puddle in a web of the block, or maybe the bell housing. It is so tight between the block and the firewall, I can’t see where it is coming from.
Is there something back there, like an oil sensor, that could be leaking? Can oil leak out, between the block and head? The block and intake manifold?
I can’t find any pictures or diagrams of the back of the engine.
The engine was rebuilt three years ago. It has an automatic transmission.
Last edited by Indynick; Jul 29, 2017 at 12:56 PM.
I have an oil leak in the rear of my LT1, on the driver’s side. It is dripping down on the exhaust pipe, and generating smoke. It is puddling on the rear of the block. I can see the shiny puddle in a web of the block, or maybe the bell housing. It is so tight between the block and the firewall, I can’t see where it is coming from.
Is there something back there, like an oil sensor, that could be leaking? Can oil leak out, between the block and head? The block and intake manifold?
I can’t find any pictures or diagrams of the back of the engine.
The engine was rebuilt three years ago. It has an automatic transmission.
The front and rear of the intake manifold is sealed with rtv and are prone to leakage over time. They are known as China Walls.. it's not a difficult fix but you will need to tak your time a read up on it, if not familiar. Ozzstar has a couple of good videos on it. You might first try retourquing the manifold bolts
Good luck
Last edited by Drifter36; Jul 29, 2017 at 02:03 PM.
Reason: Clarity
..... Drivers side drip is usually one of the oil pressure senders on the back of the block ... one sender is for the oil pressure gauge and the other is a fuel pump override switch (in case the F.P. relay goes bad , car will get fuel once there is some oil pressure from cranking the engine) ... harder to get at on an L98 , but its still a pain on the LT1 .....
Thanks for the info. Now I know what I am looking for.
I took off the large vacuum hose, and the fuel rail cover, and there are two oil sending units. One is horizonal, and one is almost vertical. They are both mounted to the same fitting block. The base of the vertical one is wet with oil, the horizonal one is wet also, but it could be from the vertical one.
The vertical one is long, with three wires: red, yellow, and tan-stripped. The horizonal one is short, with one light green wire. Which one is the oil pressure sending unit and which one is the fuel pump override switch?
I think I will replace the vertical one, since it is the easer one to reach.
Last edited by Indynick; Jul 29, 2017 at 05:57 PM.
I think I found them in my FSM. The vertical one, with three wires, is the fuel pump override switch. I assume I need to use plumber’s tape on the threads. If I change the oil pressure sending unit, do I use tape also. In the old days, if you did that, the single wire will not make a good ground.
I realize this is an old thread, but adding to it and will update it later today or tomorrow with what I find. I have a very similar oil leak on my 95 LT1 with 76k on the clock. It's leaking high up and going down the block to the exhaust. I hope its just a valve cover gasket or sensor like the one above, but if its the china wall, then so be it and I will get it fixed. I will post back with info when I remove parts and see what is causing the leak. Hard to see in the photos I took, but there is a film of oil on the back of the engine, leaking from somewhere..
LT1 Oil Leak
