Tracing valve cover leak

[LJ06]

Tracing an oil drip on a newly purchased LJ. Hoping its not the RMS, and based on reading about others’ experiences, seems like the valve cover is the place to start looking.

Looking under the hood, seems like there is quite the build up around the valve cover. A couple of questions:
- the rear PCV seems quite loose, and is quite dirty around it. It moves/wiggles without applying any force. Seems like this could be one of the sources. Should this be tighter/new grommet needed?
- should there be a nut holding this down (rear on driver side) - pictures attached

Thanks all!

 

[Drippy]

Depends on the mileage and condition. Valve cover gasket will need to be replaced over time.

The "PCV" valves on Jeeps are a straight thru design with a smaller orifice in the rear elbow.

I'd change the grommets and break clean down the valve cover and recheck for leaks. Or replace everything including the valve cover gasket. If it still leaks, your best bet is the rear main seal going out. And there isn't anything holding down the plastic harness bridge. There are taps that locks into place.

Fel-Pro Valve Cover Gasket. #V55045BR
Front elbow - Dorman 47079
Back Elbow - Dorman 47057
Grommet - Dorman 42344 x2

 

[Rubicon John]

If you’re absolutely determined to find the source of a leak...

Clean all traces of oil off the engine with brake clean. Add some leak detection dye to your oil and begin to keep an eye on the first sign of dye after driving the Jeep a bit.

Honestly though, a rear main leak runs down the back of the oil pan and should present itself as an isolated leak.

edit: I just remembered not everyone has a UV light in their toolbox to look for dye

 

[Chris]

If you’re absolutely determined to find the source of a leak...

Clean all traces of oil off the engine with brake clean. Add some leak detection dye to your oil and begin to keep an eye on the first sign of dye after driving the Jeep a bit.

Honestly though, a rear main leak runs down the back of the oil pan and should present itself as an isolated leak.

edit: I just remembered not everyone has a UV light in their toolbox to look for dye

Solid advice right here! I highly recommend this method to anyone who is trying to pinpoint a leak without having to guess.

It really works!

 

[LJ06]

Thanks all! Will try the grommets first - was surprised how loose the PCV was so wasnt sure if that was normal.

I fully expect to have to do the valve cover gasket soon-ish, though hoping to wait out atleast until next oil change.