Purchased an a/c 2stage vacuum for my a/c repair, the unit was previously rented out and had oil spilled throughout the container, and an empty container of oil. I asked the tech if they had more oil and another tech advised he is unsure where the oil goes and that it should be good to use. The oil capacity showed 30% or less. I asked if I can use any compressor oil or if it would be a problem if I used synthetic oil the auto zone rep said to just use it how it is. I advised it could burn up- he said oh well! Be sure to check all tools purchased from behind the counter prior to leaving because these auto zone reps clearly don't give a-f I'll return it to another store and shop anywhere but here. read more