Custom Wrench for an Odd Oil Filter

My car uses an oil filter for which I have not been able to find a commercially made end cap oil filter wrench. Based on a forum for my make of car, others have the same problem. I need an end cap wrench because the oil filter peeks through a round hole in the splash pan under the engine. I made my own custom wrench. Some welding is necessary. (There are also adjustable filter wrenches that fit various sizes of filter, but these have a limited contact area for gripping the filter.)

Materials:

• 1/8 inch steel about 3 1/2 x 3 1/2 inches
• 1/8 x 1/2 inch steel bar
• 1/8 inch rod
• An old socket from a wrench set
• An extra new or used oil filter to use as a pattern (No harm will be done to the oil filter in the process of making one of these end cap wrenches.)

Tools:

• Hacksaw
• Angle head grinder with a cutting wheel
• Grinding wheel
• "C" clamp
• Vise
• Screwdriver
• Welder

I first made one of these filter wrenches when my wife got a 2002 Subaru Forester. The local auto parts store did not have an end cap wrench to fit the filter. I used a new filter from the dealer as a pattern to make an end cap wrench like the one shown in this Instructable. After buying a new Hyundai Sonata recently, I discovered the wrench required to remove the filter is the same as that required for my wife's Subaru. KIA and all  four cylinder Hyundai engines use the same filter. I do not know which KIA models use this filter.

I thought I would use the FRAM filter specified to fit my car, but all after-market oil filters, even FRAM, have a rubber gasket that is just a little undersize, and those filters begin to leak sooner or later. After learning that, I decided to use only the factory filters. They are no more expensive at the dealer than a good after-market filter.

This photo shows the oil filter from under the engine. You can see the edge of the splash guard around the oil filter. Although one of these wrenches (from a previous Instructable) could work, there is not much space for manipulating it onto the filter. An end cap wrench would be better.

I used 1/8 x 1/2 inch steel bar stock to make tabs to fit over the wrench flutes on the oil filter. These are 7/8 inch long. Set your filter on a flat surface with the open end up and measure from the flat surface to the top of the flutes.

My filter has fifteen flutes. I will space them on every other flute. That means two will be right next to each other.

The fluted end of the filter is slightly less in diameter than the open end with the gasket. I drew around the open end of the filter to make a paper pattern. Then I cut it with a scissors and taped the pattern to a flat piece of 1/8 inch steel plate.

I cut around the paper circle pattern with an angle head grinder and cutting wheel. It is an imprecise process and would have been much better if I had a plasma cutter and a setup like this one. I did not want to make the steel disc too small, not did I want it to be too large. The disc does not need to be exactly round. Some cosmetic grinding can be done later, too.

Before welding the tabs to the disc, it will be necessary to hold them firmly around the flutes on the filter so they are correctly positioned for a good fit between the wrench and the filter. I joined two radiator hose clamps end to end. See the next step for how they are used.

Slip the enlarged hose clamp around the body of an oil filter. Slide a steel tab under the hose clamp and onto one of the oil filter flutes. Push the tab down so it touches the steel disc. Carefully check to be certain the filter is centered on the disc. I used a vise for welding. Weld the tab to the disc.

At this point three steel tabs have been welded to the disc. The first couple of tabs are the most difficult to position and weld. More things could go wrong at that point. Before welding the second tab, make any needed fine adjustments in the position of the filter with respect to the steel disc. The photo shows the filter removed from the disc and tabs. Position the hose clamp so it holds the tabs in place for welding, but be careful that you do not accidentally weld the hose clamp to a tab.

With each new tab to be welded you will need to loosen the hose clamps a little and slip a new tap into place. Here you can see one of the last tabs ready to be welded.

Welding always causes things to move as they cool. When finished welding the tabs to the disc, check the fit of the filter between the tabs. The filter should slide in and out of the wrench easily now, but without too much looseness. An adjustable wrench can be used to bend the tabs a little. But, there is also a bit more welding to do, and that can change the fit again.

I added some 1/8 inch rod around the upper portion of the tabs to keep them from bending and opening in use should a lot of torque be applied to remove a difficult filter. I bent the rod to fit the circumference of the tabs. I used locking pliers to hold the 1/8 inch rod in place until I could tack weld the rod to each tab. Then I removed the pliers and finished the welds. Be very careful not to weld your pliers to the 1/8 inch rod.

No matter how careful you have been, the filter may be too tight in the wrench after welding the 1/8 rod around the upper part of the tabs. Do a little grinding on the inside face of each tab. Push the wrench onto the filter without forcing it too much. Remove the filter. Look for paint that left a mark on the tabs. These marks indicate high spots where a little more grinding is needed.

I went to a local tool store that sells new and used tools. A cheap import used 17mm socket for 3/8 inch drive was one dollar. I centered the socket on the bottom of the oil filter wrench and clamped it into place with a "C" clamp. Then I welded the socket to the steel disc on the oil filter wrench. As you can see, I used a grinder to remove sharp edges and give a more pleasing look.

You can see the weld bead that joins the socket to the bottom of the wrench. Here is the finished wrench on a 3/8 inch ratchet. Eight tabs is a sufficient number to remove an oil filter from the car's engine.

Sometimes the filter binds a little in the wrench. That is true also of commercial wrenches from molded ABS plastic. One advantage to this filter wrench is that the user can insert a screwdriver and gently nudge the filter from the wrench after removing the filter from the engine. When installing the new filter on the engine, just grab ahold of the wrench and pull it off of the filter. If you need more force than that, make an "L"-shaped rod and use it to pry the wrench from the filter.