Soooo no leak but I have lost 2 qts of oil in less than 500 miles. The mechanic who did the work said that he changed the oil cause there was antifreeze that leaked and u are not suppose to run it with the antifreeze in there. He used a semi synthetic 5w20 which is not what we used before. So when I complained of this he said he didn't do anything that would compromise the engine to burn the oil. So he changed the oil back to the Castrol 5w30 full synthetic that we used before but still burning the oil. My hubby changed the Pcv valve and I'm going to watch it. No leaks, no smoke, no low antifreeze. The hose to the Pcv valve did not have oil in it, so I'm stumped. The mechanic said the pistons/ everything looked good and the motor was strong. What next if this continues?