Why Upside Down Oil Filter?
 

Why does Mercruiser mount oil filters with the open end pointing down? I've tried searching for the answer but haven't found anything conclusive. I'm thinking of changing my remote oil filter to right-side-up to make filter changes less messy. Is there any advantage to upside-down? If not, why does Mercruiser do it?
---rick

I always wondered the same thing until I heard of the trick on here. When doing a filter change, loosen the filter slightly but do not remove it. Let it sit a few minutes. By venting it with the loosening, all the oil in the filter drains back into the pan and you actually wont spill a drop when you remove the filter. Works like a charm.

I would have said the open end down makes changes less messy because the filter will be drained? There's probably a more scientific answer relating to the flow of oil and catching 'dirties' in the filter but it's Mercury, so who knows........?

RR

Quick edit: Above post makes sense. Like it!

stab it with a screw driver on the bottom of the filter,which is up.:Dit drains nicely,,now the ones that are horizontal,they can get messy.

This is the trick I recommend too. In either filter orientation, they will spill oil when removed.

Huh. Now I'm jealous that mine is open end up, lol.

But you can fill yours up with fluid before installing it, so that evens up the score.

i was just wondering about that, lol. I guess you have to spin on the inverted units dry. Merc doesn't seem worried about it though.

Clearance ? in most applications there is something mounted right below the filter head

I`d rather have upside down, at least it drains out with a hole at the top .


Mine , not so much


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