Bumping this thread with new and conflicting information. After the previous signs (milky traces on the dipstick, oil in the air cleaner, dirty colored coolant, suddenly low oil pressure), we'd concluded that I'd likely blown a head gasket. This diluted the oil, causing it to be quite thin, causing the low oil pressure and increasing blowby on a tired 190k bottom end.
This was borne out further when I took the car on a probably ill-advised 120 mi trip on Friday afternoon, as when I got back the air cleaner was well filled with a frothy oil mixture that looked like hot chocolate.
At that point I simply focused on prepping a spare longblock and head Lou hooked me up with for a swap (because, really, that's only marginally more of a pain than a head gasket replacement, and gives us a chance to futz around with a pretty new engine
), but while waiting for some engine paint to dry I ran a compression test on my current engine. I did properly except it was on a *cold* engine rather than hot, and it revealed excellent 125psi across all cylinders on the first pump, 165 after three.Because I wanted to keep driving the car, I changed the oil today, hoping to at least temporarily regain decent pressure, but new oil didn't give me any more pressure than the old stuff. Also, the old oil didn't seem to have any water in it at all, it was just very black and smelled burnt (~1000mi on this oil). It also was over a quart low, on an engine that doesn't leak (except, apparently, into the air cleaner).
The final new symptom is a grinding sound that seems to be coming from the engine as it drops back to idle rpm after it's been under load (stopping at a stoplight, etc). It quickly goes away if I blip the throttle.
I'm still planning on swapping a new engine in when I get the opportunity, but does anyone have a clue what could be happening here?
Thanks,
Matt
edit: PS, probably unrelated, but my vacuum advance doesn't seem to be working (sucking on the hose at idle has no effect on rpm)