2004 Mazda3: Crankcase Oil and Filter Change

• Why Do I Want To Do This?

  • If ensuring that Mazda will honor your warranty isn't enough...
  • With use, oil breaks down and loses some of its important properties, which include viscosity, shear strength, and neutral pH. Since the crankcase oil lubricates many of the moving parts in your engine (like your main bearings, your rod bearings, and your camshafts), it is critical that your oil be able to perform its duties.




• How Often Should I Do This?

  • Every 3,000 miles seems to be the general consensus for people who are insistent upon taking excellent care of their cars. Replacing it more often won't hurt, but some will accuse you of being obsessive-compulsive. Mazda recommends a normal replacement interval of 7,500 miles and a severe-duty interval of 5,000 miles.
  • Furthermore, if you notice your oil getting thin or smelling like gasoline, it may be time to change it, regardless of mileage. Some cleaners and unburnt gasoline can dilute or break down the oil, at which point it needs to be replaced.




• How Long Will It Take Me To Do This?

  • For your very first time, plan for an hour or two.
  • Having done this a zillion times on many cars now, I usually knock it out in 30 minutes or so, depending on how long I let the oil drain out of the pan.




• Anything I Should Do Prior To Attempting This Procedure?

  • Make sure you have all the required tools and supplies BEFORE you drain your oil and can no longer drive your car.
  • You may elect to drive your car for 5 mintutes or so so that the oil gets warm. If you do this, make sure you let the car sit for a few minutes so that you don't burn yourself on hot oil.




• What Mazda Parts Will I Need?

  • Oil Filter Element
  • Oil Filter Housing O-Ring
  • Oil Filter Drain Plug O-Ring
  • Oil Pan Drain Plug Crush Washer




• What Other Parts Will I Need?

  • (4.5)qt. 5W20 (or equivalent) Motor Oil




• Where Can I Get the Stuff To Do This?

  	Part	Company/Contact	Part Number
  	Oil Filter Element	Mazdastuff.com	L321-14-302
  	Oil Filter Housing O-Ring	Mazdastuff.com	9XG0-77-18X0
  	Oil Filter Drain Plug O-Ring	Mazdastuff.com	LF01-14-312
  	Oil Pan Drain Plug Crush Washer	Mazdastuff.com	??
  	5W20 Motor Oil	Your Favorite Auto Parts Store	N/A





• What Tools May/Will I Need?

  • Small Flat-Blade Screwdriver
  • 3/8" Drive Socket Wrench
  • 10mm 3/8" Drive Socket
  • 17mm 3/8" Drive Socket
  • 6mm Allen Wrench
  • Small Hook or Pick
  • Oil Filter Wrench [optional]

The Procedure

	Raise and Support Front of Car
	I used a floor jack to raise each side of the car from the sturdy location directly inboard of the emergency jacking points. I then used jack stands to support the car while I was under it. NEVER, NEVER get under a car that is not securely supported. Using only a floor jack is not considered securely supported. [Update] On my second time doing this, I grabbed a set of ramps from a local auto parts store, and this made raising and supporting the car much easier. My Mazda3 (stock suspension) has about 7" of ground clearance at the front bumper cover, and the bumper cover extends about 20" in front of the wheel. Thus, as long as the ramps are no higher than 7" or do not reach 7" in height within the first 20" of length, they should work.
	Remove Undercover Trim Clips
	Remove the clips by inserting a small flat-blade screwdriver under the center section and popping it out. Remove the center section and then remove the outer ring.
	Remove Undertray Bolts
	There are several 10mm bolts that fasten the plastic undertray to the car. Remove these bolts so you can remove the undertray.
	Unclip Undertray
	Each side of the undertray has a clip near the wheel. Unclip the undertray and it should be free of the car.
	Remove Oil Drainplug
	Remove the 17mm drainplug from the rear of the oil pan. Make sure you have your collection container under the hole so that you can catch the oil that will drain out.
	Remove Oil Filler Cap
	Remove the cap so that the oil will drain faster and more completely.
	Remove Oil Filter Drain Plug
	Using a 6mm Allen wrench, loosen the the drain plug so that you can remove the lower portion of the canister without spilling oil everywhere.
	Loosen and Remove Lower Lid of Oil Filter Housing
	You may be able to do it with your hands, but if not, you can use a strap-type wrench or the "special tool" from Mazda.
	Remove Filter Element
	The filter element just slides out of the housing.
	Install New Filter Element
	Just slide it on like the old one came off.
	Remove Rubber O-Ring
	Remove the large O-ring from the lower filter housing lid. You may need to use a pick or hook as it's kinda slippery.
	Install New O-Ring
	The O-ring is necessary to properly seal the oil filter housing.
	Replace Drain Plug O-Ring
	The small O-ring on the drain plug needs to be replaced as well. Again, you can use a pick or hook if your fingers get too slippery.
	Install Drain Plug
	Thread the drainplug into the plastic lid and make sure it's tight. Be careful not to over-tighten it because the lid is plastic and the drainplug is metal. The writing on the oil filter housing lid says that the tightening torque is 10N*m +/- 1N*m (7.5ft*lbs to 8.5ft*lbs). You can put a 6mm allen socket on your torque wrench to tighten the drainplug properly.
	Lubricate O-Ring
	Wipe a little oil along the outer surface of the large O-ring on the lower lid of the oil filter housing. This will help ensure that the O-ring does not catch and tear while you reinstall the filter element.
	Reinstall Filter Element and Lower Housing
	Thread it on and make sure it's not cross threaded - you don't want oil leaks! The writing on the oil filter housing lid says that the tightening torque for the lid is 30-35N*m (22-25 ft*lbs), and you can measure this by putting the Mazda special tool on your torque wrench for the final tightening.
	Reinstall Oil Drain Plug
	After installing a new crush washer, thread the plug back into the oil pan and make sure it's snug. I don't have the official torque spec for this drainplug, but the 17mm drainplugs that thread into aluminum casings (like the Mazda3's oil pan) on my other car are typically tightened to 18-22 ft*lbs.
	Remove Upper Engine Cover [optional]
	If you tend to be a klutz, you might want to remove the upper engine cover so you don't spill oil everywhere.
	Fill Oil
	Refill the crankcase oil through the filler hole. It should take about 4.5 quarts if you're replacing the oil filter at the same time. Mazda recommends 5W20 oil in the Mazda3, and Mobil makes a synthetic 0W20 oil that meets these requirements.
	Replace Oil Filler Cap
	Replace Upper Engine Cover
	Start And Run Engine
	Run the engine for a minute or two, looking under the car for any leaks. Stop the engine immediately if you find any leaks.
	Check Oil Level
	Allow the car to sit for 10 minutes or so. Then, check the oil level via the dipstick and see what it reads. There is about 0.75qt difference between the "Low" and the "Full" marks, so add enough oil to get it to register close to the "Full" mark without overfilling it.
	Replace Engine Undercover
	Replace it like you took it off.
	Clean Up Your Mess
	Clean up any oil that spilled during the process and dispose of the oil containers. Take the used oil to your local parts store or HazMat disposal site and properly recycle it. Don't pour it in a hole in your mother-in-law's back yard or the EPA will become intimate with your bank account. Further, make sure you take your old filter to the HazMat site and don't wrap it in paper towels and hide it in your trash like your neighbor does. Do the responsible thing and properly dispose of your used oil and filters! And put your catalytic convertors back on, too ;-)