2.3L ('83-'97) 91 Ranger Rear Main Seal Leak

[BC32]

So I just rebuilt my 2.3L/ 4 cylinder on my Ranger. Since then I have had to replace the rear main seal about 4 times. I cant figure out why it keeps leaking. Pretty much all of the valves and sensors were replaced. I cleaned out the oil separator and replaced the PCV before reinstalling the engine. All the vacuum lines seem to be free and clear of obstructions. Today I am replacing the EGR Vacuum Solenoid(totally overlooked replacing that to begin with). Any other ideas on what could be causing this? Thanks for the help.

 

[scotts90ranger]

You sure it's the rear main? There'd be oil coming out of other places unless there's a ridge on the rear of the crankshaft... That's not the only place for oil to leak in the back, there's a couple oil galley plugs behind the flywheel too, other than that in the back is either the oil pressure switch or the valve cover. Most of my oil leaks have been either at the switch or elsewhere, my worst was the cam bolt...

 

[BC32]

Yeah pretty sure it’s the rear main. It leaks only while being driven. It I turn it on and have it idling, no leakage. Dropped the transmission immediately after a drive and the only wet spot was around the rear main. I could see here it was leaking. At one point it was a good amount of oil coming out. Oil was spread all across the undercarriage. Thanks for the reply. I’ll have to quadruple check all the plugs on the back side. Oil pressure switch and valve cover are good. Thankfully haven’t had leaks through there.

 

[Juddys123]

L

Yeah pretty sure it’s the rear main. It leaks only while being driven. It I turn it on and have it idling, no leakage. Dropped the transmission immediately after a drive and the only wet spot was around the rear main. I could see here it was leaking. At one point it was a good amount of oil coming out. Oil was spread all across the undercarriage. Thanks for the reply. I’ll have to quadruple check all the plugs on the back side. Oil pressure switch and valve cover are good. Thankfully haven’t had leaks through there.

Any update on this thread? Having a similar problem with the rear main on my truck. Recently rebuilt motor. I put a second seal in it and it still leaks a lot out, but only when driving or holding it at a high rpm where oil pressure is high. I installed a speedy sleeve over the crankshaft because of a groove in the seal surface and I’m still having problems. This is driving me crazy .

 

[scotts90ranger]

If it's leaking out of the bellhousing area while you have high oil pressure it's probably the galley plug on the back, should be a pipe plug, I can look tonight at my spare engine hopefully and get a picture.

Are you sure it's out of the back? I had a horrible leak out of the front of mine once and it turned out to be the cam bolt... the other place in the back that I've had leaks is the oil pressure gauge switch... they don't have sealant and temperature cycles or just vibration loosen them up...