Rear oil leak - new 383 rebuild

[DavidA]

Hi

I have finally installed the 383 I finished rebuilding 3-4 months ago into my Dodge Challenger. It fired up first time which was really pleasing. Runs extremely well and sounds nice and angry.

I did notice a litlle bit of oil dropping from the bottom of the bell housing. I'm assuming it is coming from the rear main seal. After running the engine for 20 minutes I drained the oil, which seemed very thin, and then put in fresh oil. I then drove it approx 2 miles. It is still dripping a very small amount, much less than before.

Is this because the seal needs to bed in, particularly since the engine has been sitting for nearly 4 months fully assembled ? Is the leak likely to improve or get worse ?

The oil pressure readings are excellent. Just hope I don't have to re-do the rear seal.

Also any advice on how to run in a freah engine would be appreciated.

Thanks in advance.

[dwc43]

Did you put the RTV on the ends where the seal meets? Did you install it facing the right direction? Is it a rope or rubber type? Rope might take a little time to seat against the crank, but not long. It could get better, but it could get worse. I've seen them go both ways. As for run in, put in the 10w40 that you prefer and drove it like you stole it or how ever you daily drive it. Change teh oil and filter at about 500 miles and inspect the oil and cut open the filter and inspect it for metal. Then drive it and change oil every 3000 miles as normal.

[DavidA]

Thanks

It is the two piece rubber type seal. I did put a little bit of RTV on the ends and I am pretty certain I have it around the right way. One thing I didn't do, on the advice of the engine machine shop, was to soak the side pieces in diesel fuel before installing. The machinist said they swell up fast doing that and can be a real pain to get it. He said once the hot oil hits them they will swell up. Maybe that is my problem. As I said the amount leaking is much less so maybe the side pieces have swelled now after running the engine. Just hope the leak stops.

Thanks again for your reply.

[MoparMarcIdaho]

The first one I ever did back in the 70s I did wrong and it just puked it out.So you have something else going on.Hope it gets better.

[dwc43]

I've always put the two piece in dry just out of the box with no problems. Hope it clears up for you.

[DavidA]

Seems to be improving but still getting just a little coming out after running the car for 15-20 minutes or so. I may have a little bit coming out of the rear of the oil pan. Will have a good look when I get it up on my friends lift.

Thanks for the advice.

[GaryS]

Big blocks have a bad habit of leaking between the seal and the seal retainer. I now put a thin film of RTV between the seal and the block and the seal and the retainer. Since I've been doing that, I've never had a leak.