Oil leak help!

[Dirtman29]

I had an oil leak (2.3L ford) that I thought was coming out the back of my oil pan. Changed gasket to a reuseable rubber type & sealed the back of the pan with RTV silicone also. Doesnt leak at idle but once it revs up it starts dripping out. Now Im thinking rear main seal (its a D4 block, 2 pc. rear main) is whats leaking. I really dont want to tear this motor down, is there anything that I can add to the crankcase to help temporarily stop this drip? Its not pouring out, but drips enough to cause concern. Thanks for any help.

[dannyracer6]

If it is an old style d4, with the rear gasket groove on the main cap, did you fill the groove up with sillicone and let it dry so that the one piece rubber will fit properly. Usually you use the one piece rubber on the smooth rear main cap. I have done what you have done and just filled the rear cap groove and then it will seal. Just thought I would ask.

[Dirtman29]

If it is an old style d4, with the rear gasket groove on the main cap, did you fill the groove up with sillicone and let it dry so that the one piece rubber will fit properly. Usually you use the one piece rubber on the smooth rear main cap. I have done what you have done and just filled the rear cap groove and then it will seal. Just thought I would ask.

Yes the block has the grooves (my pan doesnt, its flat on the ends) but no, I did not fill them with RTV. Will have to take it back out & try that. Thanks danny.
Wouldnt letting the RTV dry in the grooves act a double gasket once the pan is reinstalled, in which case (I would think) it would leak worse? I would think you would want to seal it up while the RTV is still wet. Any info appreciated.

[Dirtman29]

Update:

Took engine back out and tipped it back so oil would leak, it is the rear main seal leaking. This motor was rebuilt & ran twice but they (apparently) didnt change the seal. Still a ford original 40+ y.o. seal. Now I have never done a 2 pc., should I silicone it where the ends meet? Any help appreciated.

[mustang99]

oil leak

Took engine back out and tipped it back so oil would leak, it is the rear main seal leaking. This motor was rebuilt & ran twice but they (apparently) didnt change the seal. Still a ford original 40+ y.o. seal. Now I have never done a 2 pc., should I silicone it where the ends meet? Any help appreciated.

yes put a little silicone where the seal joins together,,,just asking ,,u are putting the seal in the correct way?it is easy to install it backwards..u should get the instructions the way it goes in,,

[Dirtman29]

yes put a little silicone where the seal joins together,,,just asking ,,u are putting the seal in the correct way?it is easy to install it backwards..u should get the instructions the way it goes in,,

Thanks for the info, I better put it in right the 1st time, getting tired of yanking this thing already! This engine still had the original oil seal in it (I can still see the OEM ford part # on it).

[Old Rob]

We recommend and use JB weld to fill the groove. Use a fine file to smooth it down to match the caps and timing cover. The silicone can pull out when you remove the gasket and if your at the track or in a hurry?
One place some of these leak from, is where the cap fits into the corners on the block. They have a very small bevel and with high rpm crankcase pressure will leak. Just Put a tiny bit of silicone in the corners when installing the cap. Found this on the one and two piece seals. Be sure to stagger the ends of the seal so that they do not line up with the cap mating surfaces.
Automotive Component Engineering www.powerbyace.com has oil pan stud kits that address the issue of the larger four corners with stepped studs. Also if you use the oil pan rails from the later mustangs it will help with a more even clamping load on the gasket.