After Reading Just The Title I Was Thinking PCV Valve. Most Oil Consumption Problems Are Not Intermittent. A Freezing (In Cold Winter Weather) Or Sticking PCV Valve Could Be A Cause.
I’m shocked at the $150 estimate. Most PCV Valves are inexpensive and easy to replace. Most can be removed and shaken to see if they rattle. A rattle sound is good. Stuck ones don’t rattle. Your’s could be stuck at one time and loose another time.
I’d check with another shop or two (could be an independent) and get an estimate on replacing the PCV valve. I’m thinking it should be less than 30 or 40 bucks, but I could be wrong. It’s a shot in the dark, but I don’t think it has to be an expensive shot.
CSA