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DIY: Spin on filter conversion (2.3 L I4)

74657 Views 84 Replies 43 Participants Last post by  calvariae
Another credit to 6tech for this one.

Frustrated at changing your oil on the 6i? The 6i's standard cartridge filter requires several gaskets and a Mazda-sourced filter be replaced at every oil change. It's expensive, and you are left with no aftermarket filter choices. That means visiting the dealer prior to every oil change for the parts, or- worse yet- having the dealer do the change. But wait- there's hope! You too can have great filtration options! Convert the lame cartridge system to a geniune happy #1 fun Spin-on filter*.
*=Now With Japanese Kanji!
How-to Convert the 6i Cartridge Oil Filter to a Spin-on Type
By Crossbow and Stretch

The 6i uses an old style cartridge based filter. Replacing the filter is a multi-prong process, which involves replacing 2 O-rings and one main cartridge all "usually" only available from your dealer, for a price around 10-15 USD. The primary disadvantage of this is the reliance on the dealer for parts (inconvient and expensive), and having to worry about proper fitment of o-ring seals at every oil change.

The Mazda 3i uses a spin-on based system which fits flawlessly on a Mazda 6i. By purchasing the replacement filter assembly, gasket, and filter, you can convert the 6i to a spin-on filter, allowing for a reduction in cost (2-3 dollars a filter instead of 10) and making oil changes extremely easy and simplistic.

Spin-On Filter Mount [Part # L301-14-310]* (Recent part# update to L301-14-311)
Spin-On Filter Gasket [Part # LF01-14-342]*
Spin-On Filter [Part # LF10-14-302]*
Oil Drain Pan
Phillips Screwdriver
6.5mm Allen Wrench
10mm Socket
15mm Socket
76mm Oil Filter Socket Wrench (Or Strap Wrench)
Socket Wrench (3/8)
Socket Wrench Extension (6 inch)
1 Inch Wrench or Adjustable Wrench
5 Quarts of your favorite oil. (0w-20 mobil1 in this article)
Brake Parts Cleaner
Paper Towels (Galore)
Latex Gloves
Razor Blade/Flat Chisel or Paint Scrapper
Protective Eye Wear (From Revenge of Cartriage Filter)
*=Ordered from your local Mazda parts department.


Step 1: Put your car up on ramps/jackstands. Remove the undercover (one plastic screw, five 10mm bolts). Drain your oil (15mm socket). Remove the old cartridge filter/o-rings.

Step 2: Ok so here's the part where we make a little confession. We couldn't get the old cartridge filter out. It KNEW we were going to replace it, so it put up one hell of a fight. It attacked me viciously without remorse, and prevented all manner of tools (including dog power) from removing the cover. So here, for everyone's enjoyment is a singular photo of the pure evil which stood before us, filled with hatred and anger. This my friends, is a Mazda 6i Cartridge Oil Filter. May whatever gods you believe in have mercy upon your soul.

Step 3: There are four 10mm bolts holding the cartridge assembly in place. Two on one side, and two on the other. First I'll point out the passenger side bolts (photo'ed here) and the driver side bolts in the next step. Each photo has a secondary zoomed in variant, for those that are lost and confused.

Step 4: Here are the locations of the two driver side bolts. Additionally the Oil pressure connector and sensor assembly is pictured. This will have to be eventually removed to transfer to the new assembly.

Step 5: Before continuing further, make sure to remove the oil pressure sensor plug. Its got a tab which sits on top of the sensor assembly. (Where the large 1 inch nut is). Press down on the tab and pull it out. Failure to do this step could result in the plug being jarred and possibly damaging sensitive electronic gizmo thingys. After the plug is removed, if you have a wrench to remove the sensor assembly, remove it now to make the next step easier. You can remove the main assembly with the pressure sensor still attached, if you have the proper extensions to your socket wrench.

Step 6: Start loosining the four 10mm bolts on the main assembly. WARNING!: The filter will defend itself. Crap will fall. Crap will get in your eyes. Your children's children will get crap in their eyes. Either dodge like a ninja, or wear some sort of eyeprotection during this step. The filters defenses are far greater then anything concievable by human imaginiation. Do not turn your back to it! You may find it helpful to have another human present to take photos and laugh at you when you get stuff in your eyes.

Step 7: If you haven't already drained the filter (like us) this is what happens the second you loosen a single bolt. Oil goes EVERYWHERE. (Yes into your eyes too in you don't dodge like a ninja). As the oil falls, reflect upon the steps you should have followed (ie: Draining filter and removing it, wearing eye protection). Eventually the oil will stop spraying/draining everywhere, and you will be able to continue removing the four 10mm bolts. As the last bolt comes off, try and hold the assembly upright and lower it into the oil drain pan. You do have an oil drain pan right? Failure to do so will result in more crap in your face, limbs, shirts, and hair. Many bothan spies died to bring us this information.

Step 8: Finally the source of evil has been removed. Note the "oil passages" (ooooh neat) and the "oil pressure sensor" (ooooh even neater). If you haven't yet removed the oil pressure sensor, do so now because....

Step 9: Its time to screw it in the NEW assembly. (Part # L301-14-310) Huzzah! Hurray! Death to the Cartridge system! Kittens and Puppies for all! um back to install. If you have some thread tape, you can use it to replace any lost during the inital removal of the sensor. Otherwise you might find it useful to turn an extra revolution (when reinstalling the pressure sensor) to ensure that the remaining thread tape is securely in place. Next its time to prepare the old mounting surface....

Step 10: Clean the matting surface of the old gasket as best as possible. When you remove the old filter assembly, some of the gasket may be left behind. Using a combination of parts cleaner and a razorblade/paint chisel scape off and remove any remaining material. Use paper towels to ensure no cleaning chemicals get in the oil passage ways.

Step 11: Apply a thin film of "NEW oil" on the gasket surface of the new spin-on filter assembly. This will help to hold the gasket in place while you mount the assembly.

Step 12: Put the new gasket in place (Part# LF01-14-342). Make sure the tab's are pointing down as indicated. (Like the original gasket was setup).

Optional Step: Laugh at the old cartridge filter assembly by showing it its faster and shinier replacement.

Step 13: Attach the new assembly/gasket. Hold the unit in place and lightly hand tighten the four 10mm bolts in (Note that the oil pressure sensor is already connected before the assembly is in place). Hand tighten all the bolts down. Then torque the bolts down in an X pattern, left-right, right to left.

Step 14: Reconnect the Oil Pressure Sensor Plug.

Step 15: Lubricate the Spin-On Filter (Part# LF10-14-302) and pre-fill it with oil. This allows for the car to reach oil pressure faster on startup (as oil no longer as to fill 0.5 quarts of filter space before pressurizing).

Step 16: Install the spin-on filter onto the new assembly you just installed. Bask in the glory of the simplicity of such a system, and hand tighten the filter to 11-14 ft/lbs.

Step 17: Refill the car with oil. Remember that the 6i takes 4.5 Quarts of 5w-20 or equivilant oil. For oil recommendations check...

Step 18: After refilling the car with oil, check for any obvious leaks by the new assembly or drain plug. If there aren't any, start the car and let it run for a few minutes. Check for leaks. (The car is obviously still up on ramps). If you don't have any leaks after a few minutes, you might want to consider giving it a short drive around the neighborhood, then going back up the ramp and checking again. If everything checks out fine, then put the dust shield back on, and your good to go! Congratulations on a successful install.

Special thanks to Stretch for being the guinea pig for this conversion!

----Filter Oversizing Info----
Thanks to Otaking for the info on oversizing the 6i filter after the conversion is complete.

Purolator Info-
PL20195/L20195 = oversized
PL10241/L10241 = stock

The filter that works is from a 94 Mustang V6 and has the same pressure valving, etc.
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Haha, that's the group of items I'm doing next oil change too.
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