backside oil leak(s)

With the transmission off I can get a better idea of what's going on with my oil leak that drips out of the inspection cover.

It doesn't appear to be the rear main seal. If that were the case I would expect the flexplate to have oil on it, and it doesn't. The torque converter is also completely dry. However the inside of the bellhousing, on both the transmission and engine side, are all wet with motor oil.

I have oil pooling on the starter bolts and dripping onto the downpipe, which explains the smell.

Basically I see oil everywhere and can't really yet determine where it may be coming from. Logically since oil doesn't drip upward, the oil is either being slung and thrown everywhere by something rotating while simultaneously not getting the flexplate wet- which seems impossible, or the oil is coming down from the very top and running down into everything. That seems a lot more likely.

I did redo the intake manifold which I would hope have sealed it, but I may have not done a good job there.

Aside from that, and the oil pressure sender possibly leaking, what else should I look for back there?

1. Intake
2. Oil pressure sender
3. Valve cover gaskets

Yeah I probably won't need that tool. I appreciate the experience behind the answers, some of you have built more motors than I've ever touched. You know who you are. I see oil coming out of the inspection cover and there you go.

It's such a mess back there it's hard to see what's going on. There's oil everywhere. Also I never really could see that the oil pressure sender appears to be screwed into an adapter which is screwed into another adapter that's screwed into the engine.

I'll be cleaning it off now that I can get behind it, and we'll see what gets soaked first.

On the plus side, the transmission and crossmember are very well preserved. There's a good 2mm of geasy dirt crust over everything. No rust to be found on the underside of the car, that's for sure.

I got some pictures with the inspection camera which helped a bit to see what's going on.

I see there's some blobs of RTV meaning I probably put too much on.

Oddly there's oil on top of the cured RTV in spots, though most of what I can see looks ok.

I'll share some pics for commentary!

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Find one of those extendable mirrors on a stick at the local parts house, then check everything up high at the back of the engine. I did the intake and valve cover routine on my LT-4 in the Roadmaster then thought I had messed up somehow because the oil still freshly covered the inspection cover, starter, and the oil cooler adapter area. Mirror and a bright light showed no leaks up high so I concentrated on the lower part fearing it was the rear main seal. After thoroughly cleaning everything I found it was those despicable gaskets between the engine block and oil cooler adapter. Tried everyone's replacement gasket sets, even factory GM but I still have a nasty mess. The GM gasket set held the longest, made it for over a month before leaking again. Anyone have a real cure ? Oh yeah, the LT-4 came from a 96 Corvette the Ohio wagon's previous owner's wife wrecked. Wish he had put the six speed in the wagon too.

Hill billy it's about time you posted some pics of your four wagons,. the LT4 engine sounds interesting,.
I,d like to see pics of it,.

Just went through this on my 95. Leaking oil cooler adapter seals.it was slinging oil all over both sides of the engine. The first gasket set I bought was from Dorman. Junk. A buna oring (black rubber) that won't last anytime under the engines heat. I bought a fel-pro set, it came with a silicone oring and a square cross section ring. I used that square ring, it's been working great so far.....
Hope this helps

Ed

I'll re-check the oil cooler and see if that's still causing problems. Off the top of my head I can't see how that makes such a mess, but I am definitely familiar with how they can leak!

With oil leaks it;s easier to understand how the oil migrates from point of origin by doing a simple experiment,.
take a cup of water and throw the water out of the cup out of the window at 70 mph,. then try and pin point where the water landed,.

phantom 309 wrote:

With oil leaks it;s easier to understand how the oil migrates from point of origin by doing a simple experiment,.
take a cup of water and throw the water out of the cup out of the window at 70 mph,. then try and pin point where the water landed,.

Hah! that does seem to replicate what I see.

I think (hope) I did find where this leak is coming from, thanks to the UV dye method.

The grommet for the crankcase breather hose was leaking quite a bit. I ran a bead of black RTV around the lip, we'll see if that holds it in.

lamune,

Where is the crankcase beather hose and grommet? My '95 BRMW engine has the same problem and I changed the valve cover gaskets with no change.

Thanks


Chris

It's on the top of the passenger side valve cover, toward the firewall.

It was not easy to see the leak visually, since the oil is black, and the cover is black.

I put UV dye in the oil, and I spotted it with a UV light.

It's also a case of one of those "I already fixed that, it can't be leaking from there" things.

When I changed the valve cover gaskets I used Ultra Black RTV II to "glue" in the oil filler tube as the whole valve cover was coated in oil. I cleaned the valve cover. I also cleaned off the rubber breather hose grommet. I noticed a while ago that the grommet is wet again. I will use ultra black RTV on it and make sure the hose is intact, not plugged, and hooked up properly. I still am smelling hot oil when stooped.


Thanks

Chris

That's exactly what I was experiencing. I also used RTV on the oil filler for the same reason.

I just removed the grommet, cleaned it and the hole in the valve cover, ran a small bead in the grommet's groove and reinstalled it. No oil's come out since.