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.