Changed the rear main yesterday while engine was still in car, started it up and drove it 30 min or so. Noticed still leaking, i even got the famous red seal from Dvorak. Any ideas ? the valve covers dont apear to be leaking or the oil sending unit either. After putting new oil in car the first few drops i did notice was the old darker or dirtier oil. The only thing i can think of is maybe a bad rear cap ? any suggestion would be appreciated. Could the oil be comming from one of the plugs in the back of the block ? I remember putting in a new cam plug but didnt use any sealer, just a thought. thanks

What's the story on the engine? Rebuild? I fought a rear main on mine for about 2 years after I rebuilt it, small block. 3 seperate times I took my trans out, once I siliconed the cam plug, once I changed the rear main in the car, no improvement. Finally I yanked the engine, and changed to a rope seal.

Here's what my problem was, the crank was wore where the seal was suppose to seal. I happened to have a brand new crank to measure, sure enough mine was about .010" too small, so it wouldn't seal. I tossed the rope seal in it, no problems since.

Front seal on the tranny?

engine was rebuilt and it has leaked ever since, the crank was standard so im not sure what the deal was. Im getting a little upset with having a new engine that leaks. Thought i would try the other seal same crap. I guess i will take out the trany and see if anything is leaking behind the block, rope seal maybe the next option

I just changed mine turn out it was in backwards, no more leaks.

What does the surface of the crank where the seal rides look like? You may need a sleeve on there if its worn or has grooves in it.

What type of plug did you put in the back of the cam? Was it a concave plug with no lip? If so, did you install it properly? I do think you should have put some sealer on it before installing. I always do. That in itself could be the leak. Mike

the crank looks ok, but i didnt mic it, maybe the rope seal will work, its just very frustrating, the plug was concave , but i dont for sure know if thats were the leak is, until i pull the trans.

How did you install the plug?

i didnt put any sealer on it

Did you flatten the plug out when it was installed?

If you look real carefull you can tell if its a rear main. Look up above the pan inside the crank flange. If its dry the oil is coming elsewhere. Is the upper rear china wall (the block portion behind the intake) dry? If so that leaves the 2 rear oil galley plugs or the rear cam plug.
Doug

Its not a crank from a boat motor is it?????

did not flatten plug, and no the crank is not out of a boat

The concave is there for a reason and when you install the plug properly it flattens out and locks in place and with no sealer it very well could be leaking. Mike