Hey there im new to the jeep world and i have an 89 cherokee 4.0 auto. Is the pcv valve supposed to be running into the air cleaner box? most of the other ones i have seen on everything else go into the intake or throttlebody somplace.The valve seems to make noise when i shake it but if i open the oil fill cap after i shut it off it makes a woosh noise like its has pressure any help would be apprieciated

 

First off, Merry Christmas- hope yours is better than mine. I am stuck in a motel away from my family listening to 18 wheelers passing less than 50 feet from my room.

On to your question, and if I err, I hope someone jumps in for a correction. I have no direct experience with an 89, but I have a 94 and a 00XJ and I assume that these 4.0s are almost the same as yours. The valve cover on both of mine have three openings. The middle one is the oil cap and has nothing to do with this. The front one has a plug with a (roughly) 1/4" inner diameter that leads from the valve cover to the air box. The back opening has a similar looking plug that has an inner diameter (more on the importance of this later) smaller than 1/8 inch. This plug goes to the intake and supplies a metered amount (through the small hole) of vacuum to create a negative pressure in the valve cover.

Extra credit- does your airfilter get covered in motor oil? The back plug can clog over time and oily air will then be drawn into the airbox hence oiling your air filter. Solution is to replace or clean the back plug. I would replace since they are hard not to destroy in removal and they only cost about $3 plus $2 for the new rubber grommet that will most likely get destroyed as well in the removal. Just replaced both grommets and the back plug on my 00xj last week- about a 40 minute job as I also swapped out a leaky valve cover gasket.

Hope this helped.

 

My 89 doesn't have a PCV. How about a pic.

 

my 89 has a plastic elbow that is90 degrees and runs to the lower part of the back of the intake... no PCV...

 

What I did on my truggy was I replaced the back plug with a pcv and grommet from a 4.2, then run it with some 3/8 vacum hose to a brass airchuck. I took the chuck that was on the intake and replaced it with a brass one.

 

Allright thanks everyone i will have to go and investigate a few things beings all the roads are closed and we are in the middle of a blizzard fun stuff. I havent been on here enough yet and i dont even have a pic of my xj so i will have to figure it out

 

 

There is no positive crankcase valve, just the crankcase valve. There isn't a filter in the plastic pieces on the inside of the two valves. One has a larger diameter and goes to the air box. The other has a smaller diameter and goes to the intake manifold. I met have settled the diameters... There is a rubber grommet between each valve and rocker arm cover.