CCV on 97XJ

97XJ, 4.0, AW-4, 231J. 160,00 miles.


I am told that the 2 tubes that connect to the top of the valve cover are part of the CCV system.

One tube goes to the air cleaner box.
The other connects to what?

How do I clean/maintain these components?

Thanks,

Jeff-97XJ

On my 96,the front one runs to the air cleaner.The rear one go to the intake manifold.
I don,t think any thing needs to be done except check that the hoses are not pluged or cracked.
Wayne

Wayne Sihler said:

On my 96,the front one runs to the air cleaner.The rear one go to the intake manifold.
I don,t think any thing needs to be done except check that the hoses are not pluged or cracked.
Wayne

Click to expand...

Hmm... which reminds me... my back hose is fine, but the front one cracked in two. Tried taping it up as best I could... what effect would there be if it's not exactly airtight?

If you disconnect the hoses, you can twist the things that are stuck to the valve cover about 90 degrees backwards, and then lift them right up. You should check, mine were totally clogged with old oild and soot remnants. Don't mix them up! The rear one, which goes right into the intake manifold has a restrictor in it, causing the vacuum to draw air through it at a slow and steady pace, effectively ventilating the crankcase and drawing the oil fumes into the manifold to burn it in the cylinder. The other hose at the front draws fresh air from the air filter.

If the front one leaks, you risk drawing dirty air/dust into the valve cover and engine. If the rear one leaks, your engine is sucking "false" air, so it won't run properly, effectively being a vacuum leak. I guess both should be airtight, but the rear needs to be totally tight! (The front doesn't suck that much)

My knowledge is limited to my 1993 4,0 HO from a ZJ, but I think it's the same with XJ.

Check out the Cherokee America pages, there is an article there on maintaining the CCV system. Good tip for ensuring that your CCV doesn't become a secondary oil filter. Note that the major problem is with the early HO's but will be quite helpful for newer also.





cherokee america

if the rear one get clogged the pressure will blow out the front tube and oil your airfilter... the best way to clean it is to remove the entire valve cover assy and disassemble and clean each piece individualy with carb cleaner... there is a metal "flapper" under each of the fitings that likes to trap junk.. dont just pop out the fiting from the top if you have time to take it all apart.
mike