I changed my oil today, and i keep finding more and more **** wrong with my car. When i took off the engine oil cap there was **** dirt crud **** in the cap and im assuming in the heads. What is it from and what do i do to get rid of it?

o and whats the best oil to use for a car with 80,000+ miles?

 

Yeah, moisture, oil vapor and whatnot accumulate there. Probably worse if you do any short distance driving where the engine doesn't warm up fully. I just wipe it out and lube the O ring to keep crud from the outside coming in.

Opinions on oil are many. I currently use Mobil 1 0W40.
BTW, your engine is just getting broken in good. (see sig)

 

that's probably just sludged oil. Yes there will be more of this in places throughout your engine where oil doesn't actively circulate. It's not harmful, but if you want to clean it out there are ways.
You can clean the top end out (intake, cylinders) with top-engine cleaner (sea-foam). You can clean out the bottom end and oil passages with a different engine cleaner (this stuff you put in, run for 5 minutes, then change the oil).

After 80 thousand miles this isn't a bad thing to do.

Synthetic oil doesn't sludge much, if any. Using synthetic from here on will minimize the sludge buildup.

 

The cap is cooler than much of the rest of the engine area. As such, it will be a place for condensation to develop. I check and clean the underside of the cap at every oil change and use it like a "canary in a coalmine."

A long time ago I had relatively new 88 4wd Chevy w/350. I had a crack between #4 & #6 cylinders in the lifter valley. The first indication there was anything wrong was a light tan sludge (oil/water emulsion) on the underside of the filler cap. Wound up having to get a new block under warranty and I've been pretty **** about checking it ever since.

I was using synthetic oil at the time and there was hardly any junk under the cap at any time. I did a lot of highway miles and there was little chance for any condensation to develop. Shorter trips will tend to develop crud under the cap.

 

Are you still running a PCV system? I tried running breathers in the vavle covers and noticed simular crap built up in the oil fill tube where I had one breather. I went back to the PCV after one oil change, and not seen any more of it. My hands smelled like gas when I wiped it out, so I am sure the vapors were trying to escape until they mixed with moisture to make the stuff.