Manager Forum

Calling all the JEEP guys!!!! I got a 1989 Jeep Wrangler with a 4.2L engine, manual transmission that got 143,000 on the clock that has the traditional oil leaks on the rocker cover and tremendous blowby coming out of the breather at the rear of the rocker cover. This thing runs great and looks good but it gots a bad problem. I am aware that there has been some issues with these engines and oil leaks. What have you fellows found to be the fix for this owners gem?

If it has that much blow by the only fix I have found is a rebuild.

i do believe that there was or still is an updated valve cover. the pcv system has a habit of plugging and the lines deteriorating.

Is there any way to determine blowby that is excessive? That may be a rather elementary question but this customer will want to know details. BTW he does have the new stamped steel rocker cover on this engine. New PCV valve also. I checked vacuum with a gauge and at 900 rpm it holds a rock steady 21" of vacuum.

quick rule of thumb i use is take oil cap off and place hand over opening. you should feel a slight pull on you palm. if your hand is being forced away, too much blow by. if it's not burning oil, all ports are clear, and you're getting good pull at pcv you probably have a cracked compression ring. with that kind of mileage, yank it and put in a jasper unit.

So ? what happened?

Owner opted for a Jasper unit after considering some other options.

Thanks for asking. Sorry I didn't post it earlier.