When no oil leaks are present, the only way oil could be disappearing would be via :
1. Valve seals.
2. Piston oil rings.
3. Intake manifold via the PCV.
For any of the above conditions to occur, it would not use up half the oil on the dipstic mark, it should be almost 1 quart for that amount, unless the engine is smoking badly from the exhaust.
Top up the oil and check the oil under the same conditions, ie before start up every morning. After starting the oil level might be different as some oil could be trapped somewhere and not getting down to the sump fast enough.
Saturday, May 29th, 2010 AT 8:54 AM