Member
Take off your valve cover and clean the crap out of the inside. Take off the ports inside and clean them as well. Don't worry about the little gaskets that will break when you take them off.
Then get a new PCV and CCV elbow and tubes.
Good time to put on a Felpro VC gasket if you don't have one already
Then get a new PCV and CCV elbow and tubes.
Good time to put on a Felpro VC gasket if you don't have one already
CF Veteran
4.0s have no PCV, it's just a CCV system. The grommet on the back of the cover feeds crank case fumes into the intake while the one on front is supposed to suck in clean air. Since the newest XJs are 13 years old now, most suffer from a little blow-by due to worn piston rings. No big deal. Just be sure to check and clean that back grommet and hose with your oil changes.
CF Veteran
On top, in the link in my signature is cruiser's tips. This is #25. IT HAS A LINK THAT WOULD NOT COPY/PASTE.
Cruiser’s Valve Cover Mod
Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.
Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets.
Cruiser’s Valve Cover Mod
Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.
Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets.