Subaru o/f drainage-mess

[ARCOgraphite]

With the engine off there is 5 QTs in the sump. Probably room for 6 QTs.

When I turn the engine off the oil in the filter does not drain back into the sump. But drain the 5 QTs from the sump and the oil will drain back out of the filter. How does the filter know if there is any oil in the sump?

Once could postulate that since the filter is at the highest point of the engine, when you drain the pan, the oil pickup is uncovered and air can now travel up to the filter inlet. But with the adbv in the way and some oil likely in the oil pump, I really don't see this happening.
I think its just the "time" involved in draining the oil allows the mains to leak and the filter to empty.

We have had 4 Subaru with FB25 and FB20 the employ a top mounted filter.
Every time I have changed the oil, the factory blue Fram filter has been empty.
I change the oil approx 1-3 hours after a hot shut down.

Also with PCV - or even before - the idea of removing the oil fill cap or pulling up the dipstick
to aid drain speed or quantity is a myth.

This is much easier to change than the old EJ 253 with the exhaust and heat shields wrapped around the filter.
That motor required a cup wrench and extension to to tackle that job without frustration.

- Ken

 

[HemiBenny]

However, there was a bit of a mess from the oil draining from the drain plug and flowing back into the plastic shield. I had it on front jack stands. I think next time I’ll lower it when pulling the plug.

You can take a piece of cardboard or something to make a funnel-type shape to stick up there to catch the oil and drain it straight out. Another thing would be to jack the back of the car up to make it level, I do this when changing my SIL's oil in her Subie because I'm rotating tires as well.

 

[t1snwrbrdr12]

Unscrew 1/2 turn. Lift vehicle to drain oil and rotate tires. When those two items are complete, lower vehicle and slowly unscrew the filter.

Basically the filter needs time to drain, but in order to do so, loosen it a little first.

I do this on every top of engine filter and it works great to rid the oil from the area and makes for a clean filter change after the oil drains. Cartridge style I completely unthread but leave in the housing, though.