I have an 85 XJ with 2.5l with carb. During the really cold weather I was having trouble getting it started. When it warmed up I started working on it and took the top off the air cleaner and half way around the air filter it was full of fluid. Near the back where the air is supposed to be pulled into the valve cover by the PCV system it was milky looking, and I even found oil down where I took the flexible duct off the metal snout of the air cleaner. The oil to me seemed to have a gasoline odor also. Cleaned it out and seems that some of the paint was dissolved there also.

I checked the compression and 2, 3, 4 were 110, 100, 100, (couldn't get the compression tester on 1 because of the AC compressor). 2 plug was black sooty, but not oily, 3 was so clean it looked like it had never been used, and 4 was slightly black but not oily. Plugs have about 4k miles on them. Changed the oil with 4k miles on it and it was black but not burnt looking or milky, slight gas smell. When it first starts there is quite a bit of white smoke/mist coming from the air inlet port of the valve cover, once it warms up it isn't so bad, but at start up you can even see it coming out through the little filter inside the air cleaner if the top is off.

Could the cold weather be causing enough condensation in the valve cover/air cleaner to cause the milky oil in the air cleaner?

Unless #1 has a real bad compression loss, I can't figure where all the blowby is coming from. It doesn't run badly at all which makes it not seem to be the problem.

 

It's a 30 year old 2.5, there will be blow by. How far do you drive each day?

 

With age comes blow-by, with winter condensation in the oil and air cleaner.

 

About 15 miles to work, it is running about a half hour. Definitely have to let it warm up a few minutes before leaving, takes a while for the choke to finally open.

Only has 147k miles on it, but still gonna refresh the engine once summer gets here.

 

It still feels pretty sound for its age and the compression isn't bad, just worried a little to see so much oil there. I plan on keeping it going for many more years to come.