07-24-2019, 03:45 AM
WF Supporting Member
Join Date: Jan 2014
Location: SouthEast of Denver
Welcome to the Forum Ryadboh,
Changing the Rear Main Seal isn't too difficult on a 4.2.
You are already experienced in replacing the pan gasket.
The blue rubber Fel-Pro one piece gasket is the one to use.
When replacing the RMS, I suggest removing the rear cap (obviously) for access to the seal. Then loosen the remaining 6 journal caps. Loose enough so that the caps can drop down a bit.
I bought my RMS at NAPA because, overall, I've had better luck with their parts than some of the other parts stores. I don't remember for sure, but the seal I bought might have been a Fel-Pro seal too.
Make sure that the rear cap is spotlessly clean. I used a wire brush to clean mine.
Oil the seals well and be sure to use the little white plastic "shoehorn" that comes with the seal to help start the upper half between the crankshaft and the block.
Use a small speck of RTV on the sides of the cap, making sure to not get any RTV between surfaces where the block and the cap meet.
Don't forget to tighten the remaining 6 journal caps and torque all of them to spec with a good torque wrench.
Use a dab of RTV on all 4 corners of the pan gasket according to the instructions that come with the Fel-Pro pan gasket.
For a more detailed instruction about the RMS, look for a post by Got it at last. Look in his signature for a link to several service manuals. Click on the link and then click on the manual that most closely relates to your '87. Look in the 4.4 engine section for how to replace the RMS.
BTW, are you sure your leak is coming from the pan area?
It's common for the valve cover to leak at the rear and run down the back of the motor, to look like it's the pan leaking, when in reality, it's the valve cover gasket leaking.
Good Luck, L.M.
"Wrangler....It's not just a vehicle, It's a lifestyle".
1987 YJ-4.2L-Standard Shift- Re-manufactured Carter Carb-2" body Lift-31X10.5X15 BFG KOs-190K Miles No back seat.
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Warn front bumper. Matching imitation Warn bumper on the rear.