It's my '91 XJ.

Went outside and checked the oil, found a light brown sludge about 1/8-3/16" up the dipstick. Worried, I checked my coolant level. No change; it was the same as it had been for months. Plus, the sludge itself was more of a cowhide brown, not milky white. Also, when I checked my oil just 3 weeks ago, there was nothing.

Is it possible that the crazy weather here in Shenco, going from freezing to sunny to raining, caused some condensation to build in my crackcase? Also, my Jeep sat for about 2-3 weeks with minimal driving while I had my dad's Focus. Could this stuff just be some condensation from the crankcase?

Also, I noticed that my oil pressure seemed a little lower than normal. At hot idle, it sits at about 21-24 on the gauge. Normal. However when cruising down interstate going 70-75, the needle sits just above the 40 mark, at about 41-42. But then I noticed that when I slowed down behind a big rig to 55, and then got back up to speed, it seemed like the needle was pointing just shy of 40. I am currently about 1 qt low on oil. Would this have any effect? Or was this just some kind of wierd oil physics thing that happens when you slow down and then speed back up?

 

Topped off the oil and noticed the oil pressure weird thing didn't happen again.