Custom Wrench for an Odd Oil Filter




About: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying posting things I have learned and done since I got my first ...
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.)

  • 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.)
  • 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.

Step 1: The View From Under the Engine

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.

Step 2: Make Tabs for the Flutes on the Filter

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.

Step 3: Make a Paper Pattern

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.

Step 4:

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.

Step 5: Getting Ready to Weld Tabs to the Disc

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.

Step 6: Weld the First Tab

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.

Step 7: Weld Locator Tabs Around the Circumference of 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.

Step 8: Continue Welding Tabs in Place

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.

Step 9: Check the Fit

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.

Step 10: Support for the Tabs

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.

Step 11: Too Tight After Welding?

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.

Step 12: Ratchet Wrench Interface

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.

Step 13: The Finished Product

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.

Step 14: Sometimes...

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.



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    34 Discussions

    Phil Bwillyprojetos

    Reply 3 years ago on Introduction

    The device in the video is interesting. However, there would not be room to pass the three yellow cylinders on my car.

    Phil Brimar2000

    Reply 7 years ago on Introduction

    Thank you, Osvaldo. Do not look too closely at some of my welds. They do not break, but they are not very pretty.

    fintonPhil B

    Reply 6 years ago on Introduction

    "They do not break, but they are not very pretty." Describes my welding perfectly Phil!


    6 years ago on Step 14

    EXCELLENT project !!!
    You gave me the idea of welding my cap type oil filter wrench to a used 3/8" socket, or better: a universal joint surrounded by an steel spring or short piece of rubber hose, so that the extension I need to reach the filter in one of my cars (VW Jetta IV) maintains it more or less aligned to the extension but provides some misalignement capability.

    The thing I DON'T like about the sheetmetal can type of oil filter wrenches, is that the cap has a simple square hole in it, so that it is all too easy to loose the connection between the ratchet extension and the cap wrench, specially when the filter end is domed and tends to push the extension end out of the cap type wrench.  With a socket or a stiffened universal joint, the fit will be much more secure!

    Quoting from your Bio: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects...
    Let me tell ypu that I miss those magazones too. Too bad present day hobbies are to haevy on video games/computers/iPads etc. and too slim on mechanical crafts and projects.
    As I have a little (2 year) old baby, I plan to give him a "Meccano" type of toy, in order to pormote his building abilities and gusto.

    Best wishes and please continue writing more Instructables like this.
    Amclaussen, Mexico City.

    3 replies
    Phil Bamclaussen

    Reply 6 years ago on Step 14

    Thank you for your comments and thank you for looking. I expect the fear of lawsuits may have reduced good DIY articles in magazines. Back in the late 1950s and through the 1960s there were articles on converting circular saws to bench or table saws. Other than some on Instructables, one of which I did; you do not see those any longer. And, the video game craze has hurt creative DIY projects. The bright spot is robotics. It draws on the gamers, but requires learning about mechanics and electronics, too. I currently have 223 Instructables, most of which are attempts solve useful DIY needs. Whenever I get a good idea, I will publish it.

    amclaussenPhil B

    Reply 6 years ago on Step 14

    It is a real pleasure knowing people like you, with 223 Instructables, you are an Expert Instructable writter! I see your point with circular saws. Talking about this subject, I have plans to build a practical Saw Bench that can also hold a Router and/or a small Drillstand; all of them mounted in removable baseplates. This bench will have small lockable wheels, to make it easy to move and store away. The concept is sold by Skil, but I plan to make my own, larger, sturdier and even more practical. But my job leaves me little time to do my things, so that it will have to wait. Best wishes, Alfredo M. Claussen, Mexico City.

    Phil Bamclaussen

    Reply 6 years ago on Introduction

    Alfredo, I missed your comment. Here is a link to a saw bench like you want to build. Steli has been gracious in his responses to me. I am sure he would answer any questions you have.

    Phil Bmikeasaurus

    Reply 7 years ago on Introduction

    Thanks, Mike. This seems like a lot of effort in some ways, but every time I use my custom wrench, I am glad I made the effort.

    amclaussenPhil B

    Reply 6 years ago on Introduction

    I bet you save a lot of time and effort using your wrench!  As I perform al the maintenance of the three family cars, I frequently perform oil changes. But I also use an "Oil System Cleaner" bottle by Wynn's or a similar product in order to maintain clean the inside of the engine and to remove the harmful dust produced by one volcano about 35 miles from my home in Mexico City, as it is very hard and fine, and tends to destroy engines if you don't take oil changes seriously or don't have a good air filter!


    Reply 6 years ago on Introduction

    OH yeah! MOST recently (designed?) cars seem to be projected by a bunch of monkeys dressed in automotive engineers clothes!  It seems that their bosses told them to first draw the sparkplugs, filters and belts in their AutoCad PC's, and THEN start placing all the other engine components around them, to finish wrapping tightly the engine compartment sheetmetal around the resulting mess.  Amclaussen.

    Phil Bspylock

    Reply 7 years ago on Introduction

    That may work in some situations. But, if you look closely at the photo in step 1 and grasp what it shows, you will realize the filter is enshrouded above a hole in the splash pan and there is no room for gaining leverage from the side adequate to turn off an oil filter. Even if I could get enough leverage, there would be a terrible mess of old oil running over a large area.


    7 years ago on Introduction

    My car also has an odd filter that my wrenches don't fit, and there isn't much room to work in either. When I find it too tight to undo with my hands, I just wrap a short length of rope around it 5 or 6 times in an anticlockwise direction, then pull on the rope and the filter twists loose like a rotating pulley. Because I'm pulling the rope from out in the open above the engine compartment, I can really put my strength behind it and if it slips, no skinned knuckles. Great instructable. Rated.

    1 reply
    Phil Bcaarntedd

    Reply 7 years ago on Introduction

    Thank you for sharing your good idea. Some cars, including mine, would not have space for wrapping or pulling the rope because of the splash pan.