BLOWBY
 

My next problem is a oily airfilter. I just replaced my filter and its already a third of the way saturated with oil. Its bad enough, that it runs out the bottom of the airbox. I thought about putting a K & N air filter on my engine and bypassing the hose from the valve cover. Any other ideas/fixes??

uhhhh rebuild lol

You may have true blowby (rings worn) or very possibly you may have a clogged CCV system. This is a VERY common problem on 87-90 XJ. I had a bad case of it with my 88 Comanche. A clogged CCV system routes oil into your air filter box and can give the appearance of true blowby, when oftentimes it is NOT.

I recommend that you proceed as follows. Remove your valve cover. Buy a complete set of ccv hoses and grommets (approximately $45 at either the dealer or aftermarket). While you are at the parts store, buy a good quality valve cover gasket. Thoroughly clean the valve cover until you can eat out of it. Remove and replace the CCV grommets. Replace valve cover. Install new CCV hoses.

Now see where you are at. Very often, this will result in either a complete resolve of this oil in the air filter issue, or at the very least a very big improvement. I can't even recall how many times I have performed this fix on 87-90 with very good results.

If this doesn't help, a compression test is always a good data point here to determine engine condition. A good "snapshot in time". For the Jeep 4.0 engine, you should have 120-150 psi, with no more than a 30 psi variation between cylinders. Be sure to perform both a dry and a wet compression test. The wet test with a tablespoon of oil in the cylinder and then redoing the test is what tells the story on ring wear.

Here is a thread that you must read.

http://www.cherokeetalk.com/forum/f8...d-blowby-5870/

Hope this helps and keep us updated!

My '89 does this also. Unfortunately I just did my VC gasket and didn't open up the CCV :furious: Would it hurt to stick an air nozzle in it and blow it out?

Blow Bye
 

I fully have expectations of the Peep suffering blowby. 546000+ km and running dalily, I too soil the air filter. The plugs still run clean. I catch some of the oil vapour and condensate in a screen coalescer in line of the tube prior to the air box. I picked up a unit intended as a water system screener, added some barb fittings, works for me, I empty it once a week in the winter. You could consider this.