when i check the oil level after just driving the car it appears a quart low, but if i let it sit for an hour i magically have my missing quart back. anyone else have this issue? could it be a blocked oil passage because i also have excess crank case pressure. would a quart of atf help?

the engine has 150k, i just got it and do not know the previous maintenance.

 

It takes 5-10 minutes for most engines to really drain back fully, and thick oil, clogged filters etc. may take longer. You could have some head passages gummed up a bit from dino oil, but it shouldn't hold a full quart for too long up there.

With that kind of mileage on the engine, I would not worry too much, just keep up with oil changes and watch the level. If you try to run any cleaners or such through, you might end up causing leaks by breaking down the layers that have built up over the years.

 

completely normal oil behavior