Oil filter in relation to oil pump....

[gregk24]

This may sound silly to many of you, but I don't have the automotive knowledge that many here do so here it goes....is the oil filter before or after the oil pump?

Does it depend on the application? Thanks!

 

[Ducked]

After.

Oil goes from the pump into those holes around the outside of the base of the filter, comes out the hole in the middle, and hence to the rest of the engine.

 

[Shannow]

Not a silly question, as you know more after asking it.

There's another, the pick-up screen in the sump, which is really a filter before the oil pump. It's got to be only a rock catcher (pumps can swallow quite large particles, but an overly large one will sieze them solid)...think flyscreen.

 

[Kira]

Oil in a bypass filter returns to the sump after exits the filter (Ha-Ha but true). Kira

 

[Rick in PA]

By placing the oil filter after the oil pump, the oil pump can deliver full pressure to the filter.

If the oil filter was placed before the pump (on the suction side) the maximum pressure that could be developed at the oil filter would be about 14.7 PSI (atmospheric pressure). The flow rates would probably stink and you would probably run the risk of oil starvation.

I knew how the system was set-up, but I never stopped to think about the why. See, a simple question can make us think.

As I remember, there's also a pressure relief valve in the system. An oil pump is what you call a positive displacement pump. That means it forces the oil no matter what. The pressure relief valve act to limit the maximum pressure in the oil system. Without a pressure relief valve, the oil pressure would (under the right circumstances) just skyrocket and could blow out a gasket or make other mischief.

Going from memories of rebuilding an engine back in the '70s, but the lubrication system is pretty basic and shouldn't have changed.