The car lost very little oil. They did everything correct but use a cheap or incorrect filter. I wached them change the oil (0w-40) and install new o-rings. It would be nice to see the cross section of the filter assembly in the engine. The car has low profile tires and you hit a bump in the road, the filter is on a shaft upside down and the force of the bump would push it down the shaft. The grinding noise lasted a few seconds which sounded like you were gringing the gears of the transmittion. If I pushed in the clutch the noise woud disappear. The noise would stop after about ten feet. The oil does drip down in the ac clutch but the air was not on and I don't thank it would make that type of noise. AS I said the noise has stopped after the did the oil change myself.