Does the unfiltered oil enter the filter through the center and then filter out and back into the engine or does it enter the outer edges and then out to the engine through the center hole?

 

I don't know for sure---but when I prefill a new filter, the oil will only enter the filter through the center opening. If I get oil on the filter top where the small, outer holes are--the oil 'sits' there--it will not enter the filter through those holes.

Dan

 

I'm reasonably sure that the oil enters through the tube, into the center of the filter and out through the holes. I came to this conclusion because of the the direction of the anti-siphon valve that some filters have. The Motorcraft 820S is a new filter replacing the 820. The "S" however, designates a silicone O ring instead of the older neoprene or rubber rings.

DW

 

Anyone know 100% for sure?

 

Easterisland,
You've got my attention. Why the concern about which way the oil flows through your filter?

 

I'm going to get a remote filter locater and accusump. I want to find out which direction the oil flows so I can install a check valve so the oil flows from the accusump in the correct direction. I think the only one who has done this is Ruslow.
Also I figured it would be nice to know exactly which way the oil flows.
BTW, what you guys said makes sense and is probably right.

 

Well, there's one way to find out. Remove your filter and start her up.

 

That would be nice. I am having an engine built and that isn't possible.

 

It's the opposite, the oil goes in the outer edge of the filter and comes back out the center hole, where it goes first to the main oil galley. Think about this, the paper element is accordian shaped in a circle, there is a whole lot more surface area aound the outer diameter than in the middle where it is all bunched up. Also, most filters have a metal sleeve in the center with very few holes punched in it, not exposing much of the paper element. This larger surface area of the element also holds true in conical air filter designs like most of you are using. The rubber check valve that's in the outer ring where some of you were saying you couldnt pour oil past does allow flow when under the least bit of pressure, but it would shut against the out rim if oil were forced through the center of the filter. And if the check valve was at the outlet of the filter instead of the inlet, you wouldnt retain oil in the filter over a period of time. Hope this helps.

 

In through the edges and out through the center.