[Perfectlap]

Compression and leak down test. All of the money you will be spending to buy that car is for the engine. Without a running engine these cars are worth $40 and a pack of gum. Would you buy a house without checking the foundation? Of course not. You must determine the health of the engine before making an offer. Healthy engine with 40K miles is not the same as a 40K mile engine with red flags of trouble to come.

If you are absolutely serious about buying the car (post-PPI), I would make a deposit pending an examination of the oil. In other words you will be changing the oil before taking delivery. Inspect the pan, the filter is probably of no use because it may have been changed recently. Of course the pan may have been cleaned out as well but I would guess that to be atypical of the average seller. If you spot glittery things that can be picked up with a magnet in the oil...consult your mechanic on the source/cause to see if this an early warning of a $,$$$ repair.