Jeep Strokers

Has anyone had any issues with a stubborn rear main seal that insists on constantly dripping.

New build. 4.2 crank in 4.0 block and pan. Fresh from the rebuild, there was a pretty steady oil leak at the rear main seal.

Took it into the shop yesterday and we spent the morning removing the pan, inspecting the pan and the rear seal. At the time it seemed that there was some minor deformation on the corner of the seal and that some assembly lube had found its way onto the seal.

Installed new seal (with dish soap) and new pan gasket. Reinstalled exhaust and skid. Drove home, now have some oil drips at the bottom of the bell housing again. Arrrgh!

Any thoughts? Tricks?

Did you use any RTV where the cap meets the block? What about where the gasket meets the cap & block and pan meets the gasket?

One other thing. There use to be little "nubs" on the gasket to fill in the holes between the main cap and block. Some oil pan gaskets no longer have them. Instead they instruct you to fill the gaps with RTV.

Also, Check your PCV system/vent.. Any buildup of crankcase pressure will definitely cause a leak at the rear main.

There is no PCV of course. The rear metered line was connected to the intake vacuum fitting, as per stock.

The front breather connection was connected to my cold air intake.

The seal had the little tabs and the tabs were fitted into the corresponding spots on the cap.

Doesn't seem to be leaking from the pan.

Is there a possible difference between the 4.0 and 4.2 cranks where the seal rides?

Did you open the rear elbow orifice a touch ?

jsawduste wrote:Did you open the rear elbow orifice a touch ?

That will increase the 'air leak' below the TB and increase the idle speed. Hopefully the IAC can control the rpm.

Understand what your saying but not only is the bleed opened up but in many strokers I also drill a hole in the throttle plate to increase idle air flow.

Sometimes the stroker wants a little more air then what can be flow(n) through the idle IAC circuit.

I spent a long time chasing a leak in my rear main seal when I built my stroker. First, did you wash out your bellhousing with some brake cleaner after your last attempt at repair, there might have been some oil left in there that was dripping. Anyway, I changed my rear main seal twice and the damn thing kept leaking. I had a new oil pan but it was a dorman or some other aftermarket pan. After changing the rear main seal didn't fix the leak I spent the money on a mopar oil pan. Installed the new pan and tada, no more oil leak.