Disappearing Oil

[elionwyr]

Originally Posted by geozukigti

Bad pistons.... The car wouldn't run at all. Bad piston RINGS, the car would be sluggish, burn oil, the oil would be nasty at oil change time, bad MPG, smoke from the exhaust..

Ok, then I'm back to being very confused.

Here's the scenario:

* Bought the car Saturday (previous owner was a mechanic who had the car for 4 months and barely drove it, but he noticed nothing wrong with it)
* Check Engine light is on
* Checked oil - nothing on dipstick.
* Put in 3 quarts (but 5/30, which I now know is not the right oil)
* Registered halfway between non-existant and full

* Check Engine light has not turned off
* Check Oil light came on Wed
* Checked oil - nothing on dipstick
* Added 2 quarts - barely registered on dipstick

No smoke, no sluggish behavior
No sign of oil under car
Air filter looks clean
No sign of oil spraying across engine (my Shadow had a leaky head gasket so I know what that looks like)

I've had two mechanics drive it (the past owner and a friend) and neither have felt or noticed anything odd.

I'm tempted to take it to get an oil change and start from scratch, as it were. But I really thought that it sounded like a piston-related issue. So NOW what?

[geozukigti]

That's a severe oil loss! Perhaps check the oil pan gasket, or drain plug. Your valve seals could be passing oil into the exhaust too.