The 292 in my 63 F100 has a decent oil leak through the main rear seal, I had my local mechanic replace the seal but the leak is coming back right now I am loosing about a quart per 100-200 miles leaves a nice 5-6" oil slick after it has been driven around.

Any Ideas?

 

If it is, in fact, the rear main then it needs to be replaced again.

Many leaks are blamed on the rear main. So make sure it is not coming from some other part of the engine. Possibilities include:
valve covers, valley cover, rear most bolts on the intake flange, oil filter or oil filter adapter plate, oil pickup tube, oil pressure sender, any one of the oil galley plugs in the side of the block, oil pump, the two rear center oil pan studs (these should be studs, not bolts, and require thread sealer), cam plug, oil galley plug on the back of the block.
Many of those can drip down in nearly the exact same spot as the rear main.

 

I'll take another hard look at it this weekend. Can't hurt maybe I will find something.

 

It could still be the rear main seal, even though its almost new. If the rear main bearing is worn enough it will cause the seal to leak, when you drop the seal cap, also drop the main and look at the bearing.

 

Took a good look for the oil leak, I believe it is the rear of the oil pan gasket. A previous response mentioned that the two center rear bolt holes are actually studs mine are not they are bolts would this cause a problem? Any recommendations on an oil pan gasket.

 

Bolts won't really cause a problem but those two need thread sealer. And take care when tightening them because they are threaded into an aluminum retainer. The studs pretty well eliminate any risk there, though a hamfisted "mechanic" could still pull them out.
Make sure the pan rail is flat. When tightening the oil pan bolts, do not use a torque wrench. Tighten the bolts while paying attention to the gasket. If you torque them without paying attention, you'll probably squish the gasket out and it won't seal.
Any oil pan gasket set should work. Felpro is typically available at local parts stores. It's not likely that they will have it in stock but you can order it for pickup.

 

If those two bolts are causing the problem could I just pull those two bolts put thread sealer on them and reinstall?

 

Yes you can.

 

Thanks for the help

 

check out
rear main

 

I found when I did my rear main a few months back that the threads for these were stripped (but whoever worked on it before apparently didn't care). I drilled and tapped for studs.

There are lots of opportunities in and around the rear main to leak as well. If your mechanic was not familiar with Y's, he could have missed sealing something up. Good luck.

~Steve

 

I am pretty sure its fixed, it was the two back bolts on the oil pan. Cleaned off the oil put some thread sealer on the bolts and wait and wait and no oil leak, now time will tell weather or not it is fixed.

Thanks Guys

 

Still leaking, I am going to pull the oil pan and replace it when I have a chance. the truck is now up for winter updating and will not be brought down off the blocks until April.

I have a pan under the leak and noticed that I have a mixture of stuff in the oil, think it is gas but am not sure but I have not noticed any loss in coolant. Could this be coming from the fuel pump? I did notice that the P.O. had a fuel filter installed after the pump and wondered about that because I think the fuel pump has a filter on it.

 

A lot of people don't realize that there's a filter in the pump and install something inline--then wonder why the fuel flow didn't improve!

Sucks that it's still leaking. I still have a small drip after doing mine. (I think it's coming from the oil pump, though.) The fuel pump is pretty far forward of the rear main, so seems unlikely that you'd have fuel from there in the oil. Easy to diagnose with two separate drip pans, though. I had a fuel leak on a 390 (similar design) and the gas tended to drip off the bottom of the pump canister--it didn't migrate back to the rear of the motor.

Do you have power steering? Brake fluid level ok?

~Steve

 

No Power steering, and brake level is good. I am wondering if the gas got into the engine block itself, I will find out when I drain the oil.

Thanks