Hey guys, I need some help. Ever since its gotten COLD up here in MD/PA I've been leaking oil out of the rear of my 83 351W engine, but it is also wet on the engine frame cross member. I suspect that the 2 piece rear main seal that I put in after the rebuild about 700 miles ago is the culprit, but that doesn't explain the oil also dripping from the cross member for the van. Does anyone have any ideas as to anything else that it could be? I don't see any other spots that are wet on the engine other than the screw in oil dipstick on the pan. With everything else going on in my life and with it being frigidly cold I haven't had time to sit with the engine cold, warming it up to hot to find this oil leak. With the oil being cold at startup, the oil pressure has been higher according to the van's stock oil pressure gauge, but it is still in the "normal" range. When it is warm though it is down to the low end of "normal" at idle to the middle at speed. I'm still not sure if the dripping oil is coming from the back of the engine or the cross member but it is dripping fairly well. The only thing that was outside of the normal build was the high volume oil pump that I put in, is it possible that the pump also caused this problem. I doubt that they have failed this bad yet, but I have noticed some leaking at the base of valve cover gaskets. I'm also wondering if this is just a combination of several small leaks, but I haven't had time to look, especially with the massive snow storm that just passed through.
If this is the rear main seal, is it possible that it will completely fail while I'm on the road? I have to drive down to Pheonix AZ early in February and I don't have the means or the time to get get it replaced again before I leave. I do plan on replacing the seal when I get down there if that is the problem though. When I put the seal in I put it in with a little RTV at the ends where they leak typically, and a little engine assembly oil coating to prevent dry startup wear on the gasket. If anyone has any other ideas to check into please speak up, I'd like to do what I can before I have to leave short of replacing the seal. Even with my very limited driving it's going through about a quart a week, so I'm definitely going to have to keep an eye on the oil level on the drive down there.

Thanks everyone
Leon

 

I'm no expert but I don't think being cold would increase the chance of oil leaks. I would think it would actually make the oil a little thick so it leaks less.

As for things to check, if you say it's on the engine cross-member, potentially it's dripping from higher up forming up in a few places under the truck. if your valve cover gaskets are wet, I'd recommenced inspecting those close and replacing them if you take the covers off. You might get lucky and it was just the covers leaking oil down the back of the engine.

Otherwise some things to check would be potential coolant leaks dripping down back towards your engine too. I've had my Bronco have a coolant leak, which trailed some loose sludge and old oil down, appearing as an oil leak. Once I found it was coolant and fixed the leak, I had no more drips.

I don't believe you rear main seal would totally fail either on a trip. From my experience, they just start to leak more and more until it becomes a hassle to park it due to the oil stains. I've never heard of a situation were a seal fail and the vehicle dumped all its oil (not to say that can't happen, but I would be very surprised if it did.) Worst case scenario, it is your rear main again, you could just bring a couple of quarts extra oil with you and check your oil every so often on the road. My girlfriend used to have a v6 2004 mustang that would leave puddles of oil on the pavement every day she parked due to a bad rear main. She had to fill it with a quart a little more than once a week. She never got around to letting me fix it before cracking the pan on a rock, but that goes to show a bad rear main can still be driven on if needed.

 

Thanks for the reply, I finally got around to really taking some time checking for the leak when I changed the oil for the rebuild. I'm not going to discount the rear main just yet, but I did find some oil on the backside of both of the valve covers. I did get a new set of valve cover gaskets, some good rubber and steel ones this time. I couldn't find a good set of intake manifold gaskets so that I could take care of the coolant leak that I found as well. I did find some evidence of oil also leaking from the screw-in dipstick tube, but it doesn't look like it's leaking that bad so I'll try to use some Teflon tape even though I don't think it'll work. After I put the new valve cover gaskets in I'll check after a while to see if there is any oil still hangin around.