nukinfuts29

This is a Fram Tough Guard air filter, and it is only three months old to the tune of MAYBE 1,000 miles......that dark black spot smells like burnt something. Not oil, to be honest, just smells like carbon maybe? WTH is going on under my hood??

jnicewan

Its oil vapor from blow-by gasses coming out of the rubber tube that goes into the air box from the valve cover. If you disconnect the tube it might look like smoke/vapor but oil is in those vapors. Some people old school type build draft tubes for their engines when they get tired of replacing air filters and/or slobbering up their intakes and throttle bodies.

Your engine is showing signs of wear, excessive blow by gasses come from the crankcase when your piston rings or cylinder bores have wear. This condition multiplies with high speed/rpm and heavy load type driving.

huntingman2706217

There are write ups on converting your valve cover line to a oil catcher... may help in your case...

4Doors

First, remove the tube that goes from the valve cover to the air box and spray some throttle body cleaner through it to make sure it isn't blocked. I got an incredible deal on my first Jeep, a YJ, because they were certain the rings were shot (air filter looked exactly like yours). Turns out it was just the PCV system was clogged up.

huntingman2706217

Ya pcv valves are cheap and can try that first...

4Doors

Sorry, I should have said CCV (closed crankcase ventilation), not PCV. The 4.0 doesn't actually have a PCV valve, although I have read about people installing one. You have 2 hoses coming out of the top of your valve cover, and you need to make sure these aren't clogged. The smaller rear hose draws fresh air into the valve cover and the larger front hose draws the oily air out of the valve cover and into the intake to be cycled again (I could have the functions of those hoses backwards). You need to make sure those hoses and the plastic elbows aren't clogged, and you might need to just replace them as they become brittle and crack. Also, the hoses might be free and clear but the holes on the underside of your valve cover might be clogged, so you might need to pull the valve cover and clean it thoroughly.