oil in air filter

I have a 1992 xj with the 4.0 liter 6 cyl. . I am getting oil blown ontop of the air filter. It is coming from the tube of what I believe would be the pvc tube coming from the valve cover. It is enough oil saturation, when I change the air filter there is oil residue in the bottom of the air box. Is the engine not breathing properly? Is there a pvc valve? The parts store says no pvc valve? Thanks in advance for anyones assistance.

Swabby

its more like a ccv valve and its the hose closest to the fire wall

The CCV valve is a small orifice in the end of the tube that sits in the head (as 90xj06 says) and connects to a vacuum port on the intake manifold. Engine vacuum draws air from the valve cover (fumes and other nasty stuff) and fresh, filtered air is drawn in from the tube in front coming from the air cleaner. This orifice can get clogged quite easily. Take a small wire or small drill bit and clean the hole out. You can spray some cleaner in there and make sure the tube is clear.

This can also happen if you have too much blow-by. This is when your piston rings no longer seal well and combustion gases can enter the block and "overpressure" it. This excessive pressure is too much for the vacuum at the CCV to handle and the excess blows back into the air filter. You should check your engine compression to see if this is the source as well.

The inside of the valve cover can also cake up with sludge and restrict the area around the CCV. A good cleaning can also ease the oil in the filter problem.

I had a pretty bad problem with this. Turned out my CCV was completely clogged. After cleaning the orifice and blowing cleaner through the line with a compressor, it cleared up. I also removed my valve cover and scrape out all of the junk inside.

I do think I have some blow by issues. Cause??? The engine has 146,000 miles. And when the engine idles for a while it will start smoking blue smoke out of the exhaust. And I have a ticking sound which makes the engine actually sound like a diesel engine. I just went to the jeep jamboree at Snowshoe West Virginia and as we were out on the trail rides when we would come to a spot where we would wait for people to get through an obstacle and as I sat there and idled the engine would start smoking blue smoke out of the exhaust. But the smoking out of the exhaust clears up when I start rolling again. I have good oil pressure. I have not ever actually done a cylinder compression check. Thanks for your thoughts and help on the issue.

V/R
Swabby

swabby said:

I have a 1992 xj with the 4.0 liter 6 cyl. . I am getting oil blown ontop of the air filter. It is coming from the tube of what I believe would be the pvc tube coming from the valve cover. It is enough oil saturation, when I change the air filter there is oil residue in the bottom of the air box. Is the engine not breathing properly? Is there a pvc valve? The parts store says no pvc valve? Thanks in advance for anyones assistance.

Swabby

Click to expand...

You also said that you're getting blue smoke from the exhaust so it seems the piston rings are worn and are allowing combustion gases to "blow by" into the crankcase. It's the pressurization of the crankcase by these gases which is causing your air filter to become saturated with oil.
Oil getting past the rings into the combustion chambers causes blue smoke and also causes detonation which is the ticking sound you're hearing.
A "wet and dry" compression test of all cylinders will reveal the extent of the problem.