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View Full Version : fix your 4l pcv system - I did!


Fuzzydog
04-19-2006, 03:55 PM
my cherokee has been soaking the air filter with oil ever since I bought it, about a year ago. did some web searching and found out why (plugged breather line from valve cover to intake manifold.) - gotta love the internet!

I bought the new vac lines, grommets, etc from the dealership (about $100), took off the valve cover and cleaned it up really good, and put in a new air filter. oh yeah, tightened a half dozen exhaust manifold bolts while I was in there, also removed the idle motor from the tb and cleaned it up with tb cleaner as well.
now...my valve cover doesn't leak, my idle doesn't race up to 2-3k, no more exhaust tick, my air filter is still clean after 5 days and...oh yeah...the increased airflow really gives you a 'seat of the pants' performance increase. That air filter plugged with oil really restricts the breathing.

and...I was wondering something. It was suggested to use brake cleaner to clean the valve cover, which I did. Now I'm wondering why would I EVER use anything else to clean off oil, grease and grime!?!?! That stuff is the SHIZ!

In The Zone
04-19-2006, 09:40 PM
pretty much all manufactures have the same issues with pcv systems

they usually are due to neglect plugging up with years of sludge and resin from the crankcase

kootenaycat
04-19-2006, 09:55 PM
pretty much all manufactures have the same issues with pcv systems

they usually are due to neglect plugging up with years of sludge and resin from the crankcase

Except the 4.0L PCV system is even more fawked then normal, there is no PCV valve that you replace!

Thanks for the tip Fuzzy! Gotta do that to my XJ as well. But when you work on cars 8hrs/day you don't want to do much more in the evenings or weekends!

Kinslayer
04-19-2006, 10:11 PM
Yeah, you can do that mod for 20 bucks, if you are feeling really expensive. Make sure you use a nice fat hose, it won't clog up after that.

I learned this from a QUICKIE LUBE PLACE - dude was like "Yeah, these 4L's always do that, here i'll fix it for ya"

In The Zone
04-20-2006, 08:29 AM
Except the 4.0L PCV system is even more fawked then normal, there is no PCV valve that you replace!

Thanks for the tip Fuzzy! Gotta do that to my XJ as well. But when you work on cars 8hrs/day you don't want to do much more in the evenings or weekends!




see i learned somthin again [cheers]


school of FIBC rocks[36]

Smurf131
04-20-2006, 01:12 PM
jeap thrills stocks the pcv system for something like $55 i just rebuilt my 4.0l and i have no problems with anything now!

Fuzzydog
04-20-2006, 01:20 PM
what all is included in the jeep thrills kit?

from the dealership I bought the small vac line from the firewall end of the valve cover to the intake manifold (creates vacuum in the valve cover) and also a bunch of vac lines all attached together on a connector that replaces the big vac line going from the airbox to the grill end of the valve cover - also has smaller vac lines going to IM and also to the fuel rail ...FPR? I guess? I paid just over $100 for it.

Smurf131
04-20-2006, 03:16 PM
ok you got the full kit i only bought the one closer to the grill to the air cleaner the one by the firewall was fine, it probably works out the same then.

Fuzzydog
04-20-2006, 04:00 PM
yeah, I was sick and tired of changing air filters every 3 weeks just so I had any power at all - I figured I would set aside some time and do it right once and for all.
That thing better not spit any more oil into the air filter ---with the engine running, I have major vacuum at the firewall end of the valve cover - that should keep the oil vapor flowing the right direction....

Smurf131
04-22-2006, 07:52 PM
something else that helped me out before i rebuilt it was get some lucas oil heavy duty engine oil stablizer, it ups your oil pressure helps things seal and it cut my blow-by in half. it wont sludge and it blends safely with any kind of oil it also keeps your oil clean and makes it last longer. i work at an automotive machine shop as an apprentice and one of my co-workers uses it religiously and the last oil change he did on his truck was about 6000km ago and his oil looks almost new.