Getting the oil filter off

We have reached that portion of the year when boats are being tucked in for long winter naps.  This is an excellent time to change the oil in your engine so that it rests all winter with fresh, non-acidic oil.

This means that it is time to change the oil filter.  And there we are all faced with the same problem:  That filter which was so carefully installed, following the manufacturer's recommendation to only turn it 3/4 of a turn after the gasket contacts (they even paint little marks on the filter to help you determine this)?  That filter which was installed with your bare hands and nothing more?  Well it is now welded to the engine.  What went on with bare hands is by no means coming off that way.

Man is the tool maker.  No matter the difficulty, he has invented a tool to overcome it.   Removing a stuck oil filter is no exception - since the spin-on oil filter replaced the element-in-a-canister, many tools have been invented to deal with the seemingly inevitably recalcitrant filter.

On Eolian, I use a rubber strap wrench to loosen the oil filters on the engine and the generator:

Strap Wrench

This tool is cleverly designed so that the harder you pull on the handle to turn a cooked-on filter, the tighter the strap grips the casing of the filter.  It is a one-size-fits-all tool - all you need to do to adjust it is to pull on the strap.

But not every filter is mounted where there is enough free space to swing the handle of this wrench.  In my shop I have a couple of alternatives which have served me well working on automotive engines over the years. 

Mechanic's metal strap wrench

This is another kind of strap wrench - but on this one the strap is a metal band, and it has no handle.  Instead, you use your 3/8" ratchet wrench with an extension as a handle, which allows it to be used in much tighter quarters.  Needless to say, you can apply much more torque with this tool than with the rubber strap wrench.  This tool does not have the range of adjustment of the rubber strap wrench; nevertheless it has worked on every Ford and GM filter I've used it on.  It wouldn't fit the small oil filter on Eolian's generator tho.

"The Crusher"

Next is a tool that grips the filter from the end.  For really tight spaces this is the ideal tool.  As torque is applied to the nut, a cam action pulls the two grippers tighter and tighter together, eventually crushing the body of the filter.  No way can this slip.

I do not use the 'socket wrench' type of filter grippers - those cup-like things that have an interior contour like the shape of the end of the filter body.  First, all the filters are different, so you need to have a collection of them.  And they don't grip nearly as securely as the tools above.

Finally, when all else fails, more than one desperate mechanic (possibly including your correspondent) has simply driven a screwdriver clear through an oil filter and used it as a lever to turn it.  This method is crude, messy, and effective.

Whatever tool you use, it is a good idea to put on a new filter once a year.  Filters are cheap; engines are expensive. 

Now go get dirty.

Getting the oil filter off