I would like to know what the effects on an oil pump are when oil is changed.

Obviously after changing the oil filter the engine will run dry without oil pressure for the first few seconds while oil is sucked up past the non-return valve.

I know that for the engine itself this is not a huge deal as todays oils are magnetic and stick to things, but what effect does this have on an oil pump?

Does it degrade its performance in anyway? Or is the oil pump "tougher" than the engine. What I mean by excessive is every 3000 miles. To some people this is common and perfectly acceptable but I am curious to how the oil pump is affected.

1 Answer 1


Many mechanical oil pumps look like this.

enter image description here

There is very little mechanical resistance and friction occurring in this design. With very little lubrication this type of oil pump will do just fine in terms of wear.

When you change your oil the fluid in the pump will more than likely not be drained, as a result there will be some lubrication in the pump itself. This low amount of lubrication will be protect the oil pump under the conditions you specified.

I would not be concerned with oil pump damage from the results of an oil change.

  • How the heck does that thing pump?
    – corsiKa
    Dec 15, 2015 at 22:37
  • @corsiKlauseHoHoHo It's an internal gear pump or gerotor; Wikipedia explains how it works. The inner rotor turns the outer one, and the changing volumes between them suck oil in on one side and then squirt it out the other. Dec 15, 2015 at 22:56
  • yes, it works almost like a Wankel engine does Dec 15, 2015 at 22:57

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .