Rear main leaking, too much crank pressure?

[mark2215]

The intake is the stock manifold that came with my jeep. The IAT was in the pipe running to the air filter but is now located in the outlet of the intercooler. The throttle body is a BBK.

[SilverXJ]

The IAT was in the pipe running to the air filter

It came stock like that?

When you get a chance take a pic of that twist in breather elbow. Might be something else on the last 4.0Ls that they changed.

[mark2215]

my jeep had a cai when I bought it but from my research 2005 IAT was indeed located in the pipe connecting the filter to the throttle body.

Here are some pictures of the rear breather elbow.

elbow1.jpg

elbow2.jpg

[wjtom]

Ive never seen one like that either.

[SilverXJ]

my jeep had a cai when I bought it but from my research 2005 IAT was indeed located in the pipe connecting the filter to the throttle body.

Here are some pictures of the rear breather elbow.

Thanx for the info & images. Interesting little details I did not know about on the last 4.0Ls.

[SilverXJ]

Any update on the leak?

[mark2215]

No update. I've been working too much so no time to hook up a gauge to the dipstick.

[mark2215]

Ok, hooked up a gauge today. Vacuum at low throttle and pretty much goes to 0 at wot/high boost but no pressure. So now the question is, do I change the rear main seal when I pull the oil pan or just reseal the oil pan? Is there a way to tell what seal is leaking when I drop the pan? Did I mention I hate oil leaks!

[SilverXJ]

I know how you feel. I hate leaks as well. The only thing I can recommend is to clean the area well with brake cleaner, run it for a bit to cause the leak then take it apart and look.

When you pull the pan take a look at the seal as well as where the pan gasket meets with the block/main cap. There may be two pockets on either side of the main cap that are recessed. They should be filled with RTV if the oil pan gasket if missing the little nubs to fill that area. Most new gaskets are don't have that. There still should be a little bit of RTV even if the pan gasket has the numbs.

As for the RMS that is up to you. After you readings from the vac gauge I don't think you have a problem with your PCV system. Gojeep has a good writeup on RMS replacement: http://www.go.jeep-xj.info/HowtoRearMain.htm

[mark2215]

so I'm getting everything ready to pull the pan and reseal it all. One thing I just though of is my oil pan is a new dorman pan. The pan seemed like good quality but maybe it's the reason for the leak. Does anyone have any experience with dorman/aftermarket pans versus a dealer pan?

[mark2215]

I ordered new oil pan gasket, rear main seal, and the correct sealant to do the job right. I decided to go ahead and replace the rear main while the oil pan is off so I don't have to deal with any of it again (hopefully). I have another 100 miles to go before it's time for the oil change then I'll reseal everything. Hopefully this weekend.

[mark2215]

Update, I changed rms and oil pan gasket, put it all back together and at last no more leaks. The hardest part of the whole project was removing the exhaust.

I also learned it only takes a few seconds to pump 3 quarts of expensive joe gibbs oil all over the ground when you have 2 o-rings on the oil filter. At first I thought somehow the old o-ring was left behind even though I always check but nope, the o-ring was still on the old filter. The new wix had 2 on it from the package and I didn't even notice, I even pre-lubed it and missed it? I can guarantee I won't make that mistake again. Joe gibbs oil isn't cheap!