Ok all.. been working on the 88 getting it running (3.0L EB 2wd). It does run now pretty well.. definitely need some suspension work.. but that's a different post. I have had the rear main seal replaced and the oil pan gasket replaced to stop the oil leak. There is a lot less oil on the ground now.. but still leaves spots on the street. It appears oil is leaking down the oil pan from above and dripping off of it to the street. Any ideas? I also had the main cap bolts replaced (one was broken and the end was in the oil pan). Thanks in advance!

 

Check the timing cover seal behind the harmonic balancer, the valve cover gaskets, the oil pressure sending unit, and the oil filter. These are areas I've personally seen leaking on various vehicles.

A broken main bolt is pretty scary! You DID check the rest, right?

 

My local mechanic did the work.. so I'll need to double check that.. I ran the car today for a while.. then turned it off and tried to find the oil.. but with those tight quarters.. I couldn't tell where it was coming from.. kind of looked like where the transmission joins the engine.. it's back at the transmission place.. there's a transmission fluid leak.. and since the transmission is only 3 weeks old.. they are scoping it out. I'll keep ya informed!

 

Hmm...it COULD just be left over oil from your previous leaks. It does tend to migrate before it drips off. I had an oil pan gasket blow out the front and leak so much oil that it covered the subframe (5 quarts...one day), and I couldn't even find the leak.

 

check your PCV valve for plugging. should be vacuum in the crankcase, no pressure. pressurized crankcase is a sure leaker of an engine.

can also be caused by excessive ring blowby, worn/broken rings or piston ring grooves

with all the vacuum lines on these to break, it's easy to loose crankcase vacuum.

the OEM factory valve cover gaskets were cork, dried out cracked and leaked like no gasket there

 

You can check the backs of the valve covers for leaks. It could also be the intake manifold gasket; they're known for leaking. If the leaks are bad enough, they will flow down to the transmission.

I hate to say this, but if you can't find other sources from above, oil leak from the junction between the back of the engine and transmission is most likely the rear main seal, or oil pan gasket. It means they were not properly installed. I know this because I've had this problem before; leaking seal/gaskets, I replaced them once, started leaking again after about a year, now I'm ready to go into it again. I have a 4 liter engine with the cast aluminum oil pan that requires some trick to properly install, as it has to be bolted to the block and transmission together. My van is 4wd, so it's a bigger hassle to do than 2wd due to the front drive train and the tighter front cross member.

 

Oil only drips down when the vehicle is in park. If you're driving on the road the airstream under the car will spray every drop over parts located behind.
I have a leak on one side somewhere near where the pan gasket goes up the arc. Oil does collect at the drain-plug as the very end of the path. From there it either drips down where you standing or sprays over the trannys bellhousing making it messy allover, leaves the tranny as the suspect area where in fact isn't the problem.

A leak like this we call "the engine sweats".. mostly watched on elder cars with some mileage. Something to observe, if it's to much emission for the environment then the culprit must be found and fixed.

(btw: is a blue oil pan gasket original equipment for a 97 XLT RWD?)

 

Even at idle, the airflow from the fan will blow the leak everywhere. I don't think a blue oil pan gasket is factory. Ii think that's a FelPro. I think the original was black or maybe cork.

 

Here we go - Gasket must have been replaced once before with this blue FelPro. If not done properly the mess returns. not to say how complicated it is to remove the pan on the 3L engine.

 

Well... the transmission place fixed the transmission leak and said the oil leak looks like it's coming from the top of the right rear valve cover.. make any sense?

 

still having troubles!! The tranny is still leaking.. so back to the transmission shop.. the van is still leaking quite a bit of oil from what looks like where the transmission meets the engine... oil drips from there and where the oil plug is. It also appears that there is oil on the back side of the van after driving today. The main seal has been replaced... the oil pan gasket has been replaced. New head gaskets. I'm kind of a a loss.. other than the transmission place said the oil leak is coming from the top side of the right rear gasket. Does this make any sense? I don't want to move ahead with the restoration until she stops leaking! Thanks again!

 

You replaced the head gaskets? In the process, you should have replaced the intake and valve cover gaskets. If they did a good job there, there should be no leaks from the tops side of the engine.

When you say main seal, is that the rear main seal? That and the oil pan gasket should have stopped the leaks from the bottom side.

There is also the front cover, which has a gasket to the block and the front main seal.

That should be about it for the engine gaskets and seals.

If you're taking it back to the transmission shop to fix the transmission leak, can you get them to separate it from the engine to see if anything in the rear is still leaking? If you had cleaned up the oil leak traces before, the new leaks should be easy to follow to their sources.

 

Here's an article that may be of help. Revised Oil Pan Gasket Replacement for Ford 3.0L Engine: Engine Builder

Noted in the repair manuals and from experience, you cannot just replace the pan gasket and hope all will be well. The transmission bolts to the bottom of the pan exerting a pull on the pan. Before the pan is bolted down, you must measure the gap between the pan and the engine block (simplified explanation here) and install spacers to take up any gap. Filling this gap prevents pan distortion and subsequent leaks. Any Haynes or Chilton manual will explain this in more detail. It is not hard to determine the gap, but it is hard to find the correct spacer(s).

Replacing the rear main oil seal appears pretty straightforward but if you try to bang the seal in with an improvised tool, you run the risk of distorting the seal. Older engines eventually wind up with a groove worn in the crank end that will leak oil even with a new seal in place. A repair sleeve can be placed over the crank to eliminate this weak spot. The sleeve is cheap but the installation tool is ridiculously expensive.

Finally, there is a hex head plug located just below a large core plug(freeze plug) on the back side of the engine block, just above the rear main seal. This hex head plug has been found to leak on some engines, so you might want to inspect it while the transmission is out.

 

I don't think the valve cover gaskets or intake gaskets were done with the head gasket. The van wasn't running.. so we were trying to get it to run.. but now it's running.. we have to get the oil stopped leaking so it can park in the garage.. When I take it back to the transmission shop, he will take a look at it. I'll keep you all posted! Also, after driving today, I changed the wiper blades.. and noticed oil on the back side of the van.. I assume it's from the oil leaking under the car while driving?

 

Its hard to believe you could have a leak that would be severe enough to blow back onto the rear of the van. 90% of drips from the tranny/engine area would tend to accumulate on the underside of the van before ever making back to the rear end.

It would almost have to be aerosolized somehow to get back there. A more likely scenario would be leakage into the exhaust system and being expelled but this would certainly show up as a dark, badly smoking exhaust - quite noticeable. Are you certain it is oil and not some other substance?