Has anyone...
- Thread starter Joopin
- Start date
redrooster
New member
Not sure about the 4.0 specifically, but my the AMC V8's had a two piece rear main that you could replace by pulling the pan and the rear main bearing cap.
I believe the front is a one piece that is mounted in the timing cover. You will have to pull the harmonic balancer to install the front seal. Don't mess with it if it's not leaking
I believe the front is a one piece that is mounted in the timing cover. You will have to pull the harmonic balancer to install the front seal. Don't mess with it if it's not leaking
Bounty__Hunter
Super Moderator
It's not too hard to replace, I'd just do the rear main and oilpan gasket. Check the valve cover gasket as well.
Check your CCV (closed crankcase ventilation) system to make sure it's working properly. If it's not, you could be building too much crankcase pressure causing seals and gaskets to blow. Replacing seals without fixing the CCV will just allow more leaks down the road.
A sign of the CCV not working properly is oil in the air filter.
To test the CCV, find the vacuum line running from the valve cover to the airbox. Pull the line at the airbox and make sure it's sucking air into the valve cover, not blowing air out. If it's blowing air out, chances are the line between the valve cover and intake manifold is clogged.
Check your CCV (closed crankcase ventilation) system to make sure it's working properly. If it's not, you could be building too much crankcase pressure causing seals and gaskets to blow. Replacing seals without fixing the CCV will just allow more leaks down the road.
A sign of the CCV not working properly is oil in the air filter.
To test the CCV, find the vacuum line running from the valve cover to the airbox. Pull the line at the airbox and make sure it's sucking air into the valve cover, not blowing air out. If it's blowing air out, chances are the line between the valve cover and intake manifold is clogged.
shvlhd666
New member
The FSM says to unbolt the motor mounts, exhaust bolts at the collector and the starter.
My personal experience proved that you only have to remove the starter and jack up the frame until you obtain enough clearance to remove the pan.
And that's all. Took me about 3 hours and that is only because I wasn't in any hurry.
Funny thing though, I found an extra pan bolt inside the pan when I removed it. It looked brand new. Almost like it was dropped in there at the time of manufacture. Lucky that the crank never picked it up.
My personal experience proved that you only have to remove the starter and jack up the frame until you obtain enough clearance to remove the pan.
And that's all. Took me about 3 hours and that is only because I wasn't in any hurry.
Funny thing though, I found an extra pan bolt inside the pan when I removed it. It looked brand new. Almost like it was dropped in there at the time of manufacture. Lucky that the crank never picked it up.
Joopin
Super Moderator
Well let me say that the RMS went a couple years ago, started leaking like crazy. I put in some thicker oil and some additive, it slowed down and stopped almost completely. Since it was barley noticable, I let it go and didn't get it fixed for a year. It steadily got worse. I then had a mechanic fix it since he was already working on my jeep.
He told me that if you let the rear main go too long it will actually affect the inner seals as well. So if you replace the rear main and the inner seals are all sloppy than the rear main will be shot again eventually.
Now that brings me here, the rear main is shot again... so I assumed all the inner seals are shot. I was going to just build my stroker and drop it in, but with the new house and everything who knows when that's gonna happen.
In the mean time oil is getting all over my new driveway... not good.
I tried clogging up the leak with some mud, but that didn't work...
He told me that if you let the rear main go too long it will actually affect the inner seals as well. So if you replace the rear main and the inner seals are all sloppy than the rear main will be shot again eventually.
Now that brings me here, the rear main is shot again... so I assumed all the inner seals are shot. I was going to just build my stroker and drop it in, but with the new house and everything who knows when that's gonna happen.
In the mean time oil is getting all over my new driveway... not good.
I tried clogging up the leak with some mud, but that didn't work...
Bounty__Hunter
Super Moderator
There are no 'inner seals' that affect the rear main seal, that I know of.
The fact it has done it twice leads me to believe it's a clogged CCV and too much crankcase pressure.
The fact it has done it twice leads me to believe it's a clogged CCV and too much crankcase pressure.
Joopin
Super Moderator
Sweet, if it is what you say... that's a heck of a lot less work. I'll check on that vacuum. Thanks.
redrooster
New member
Bounty is correct on the seals and the CCV likely being the root cause. I don't know of any engines that have internal seals on the crankshaft. You have a front seal on the timing cover and rear main and that is all. The crank is held in place by bearing caps that need oil to live. You wouldn't want seals on them anyway.
