After 2.5 years of use it looks like my vacuum pump oil is quite dirty, or the inside is starting to corrode. Never once changed the oil. I didn't realize the oil got contaminated and needed to be changed before it ran low. Don't be like me, change your pump oil. Because let's be serious, http://www.instructables.com/id/RepairingCleaningUnsiezing-Edwards-RV8-vacuum-pu/?ALLSTEPS doing this doesn't look all that fun.