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Mazda CX-9 Engine Oil Change Guide
How to change the motor oil and filter on the Skyactiv-G turbo 2.5L I4 engine in a 2016 to 2021 Mazda CX-9.

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2019 CX-9 2.5L I4
Skyactiv-G Turbocharged
Partially Remove Dipstick
This automotive maintenance tutorial was specifically written to assist owners of the second generation 2016, 2017, 2018, 2019, 2020 and 2021 Mazda CX-9 SUV in changing the motor oil and replacing the oil filter on the Skyactiv-G turbocharged 2.5 liter inline four cylinder engine.

Owners of other Mazda vehicles such as the CX-5, CX-3, CX-30, MX-30, CX-8, Mazda8 (MPV), MX-5 Miata, Mazda2 (Demio), Mazda3 (Axela), Mazda6 (Atenza) and Mazda5 (Premacy) may also find these DIY instructions to be helpful.

A few compatible replacement canister style oil filters with their part numbers are as follows: Mobil 1 M1-108A, K&N HP-1008, Bosch 3300, Purolator PL14612, Fram PH6607, Wix 57002 and Pennzoil HPZ-37.

The total oil capacity specification in the owner's manual for an oil change with a filter replacement is 5.1 U.S. quarts (or 4.8 liters) of SAE 5W-30 oil.

Please double check your owner's manual to verify the oil capacity specification and the recommended oil viscosity (weight) for your climate.

According to the scheduled maintenance section of the owner's manual, the service interval specification for changing the motor oil and oil filter is every 7,500 miles (12,000 km) or at least once a year.

Most owners will use the "flexible maintenance interval" as indicated by the oil life meter on the "maintenance monitor" system and change the oil when the "wrench" indicator light is displayed on the gauge cluster.

It would be best for the engine to be warm enough for the old oil to flow out quickly and for most of the contaminants to be suspended within the old oil.

The tools and other items needed to complete this oil change procedure include a floor jack, two jack stands, an 8mm socket with a 1/4" drive ratchet, a flat head screwdriver, a 17mm socket with a 3/8" drive ratchet and possibly also a pop rivet removal tool.

The first few steps are to open the hood, partially remove the dipstick an inch or two and spin off the oil filler cap in the counterclockwise direction.

Removing the oil fill cap and partially lifting out the dipstick will help prevent a vacuum from forming and also allow the old oil to drain out faster.


Spin Out Oil Fill Cap
SAE 5W-30 Oil Type
Raise Front of SUV
Set the oil fill cap aside in a safe place.

The oil fill cap in this 2019 CX-9 AWD had SAE 5W-30 printed on it.

Engage the emergency / parking brake and place wheel chocks on both sides of the rear tires to help prevent the vehicle form moving.

Carefully raise the front of the SUV with the floor jack and securely support it with at least two jack stands.

Plastic Skid Plate
Oil Service Access Cover
Loosen Counterclockwise
Slide under the engine bay with the 8mm socket, a 1/4" drive ratchet and a flat head screwdriver or a pop rivet removal tool.

Locate the oil service access cover on the plastic under engine cover or "skid plate".

Remove the two black metal screws by turning them in the counterclockwise direction with the 8mm socket and a 1/4" drive ratchet.

Loosen Second Screw
Pry Out Button - Unlock
Pull Out Pop Rivet
Set the two screws aside in a safe place.

There are also two black plastic pop rivets that secure the oil service access cover in place.

Use the flat head screwdriver to pry out the center pin or "button" head in the middle of each fastener to unlock it.

Then pry out the base of the fastener with the flat head screwdriver or use the pop rivet removal tool.

Remove 2nd Pop Rivet
2 Screws & 2 Pop Rivets
Pull Off Access Panel
Set the two pop rivets aside with the two screws.

Carefully pull the oil service access panel out of the under engine cover or "skid plate".

Set the service cover aside in a safe place.

Oil Pan & Old Oil Filter
Used Oil Catch Container
Loosen Counterclockwise
Once the cover is out of the way, you'll be able to see the black metal oil pan, the black metal oil drain bolt and the OEM oil filter.

Slide the used oil catch basin to just below the oil drain bolt.

Loosen the oil drain bolt by turning it in the counterclockwise direction with the 17mm socket and a 3/8" drive ratchet.

Be careful when you remove the oil drain bolt. The old oil might still be hot enough to burn your fingers.

Spin Out Oil Drain Bolt
Drain Out Old Oil
Tighten Oil Drain Bolt
Spin out the oil drain bolt the last few turns with your fingers to avoid having it drop down into the catch basin.

If the oil drain bolt is equipped with a crush washer or "gasket", inspect it and replace it with a new one if necessary.

The compatible replacement oil drain bolt washer part number is Mazda 9956-41-400 (also known as 9956-41-400-PT).

Allow the old oil to drain out for at least a few minutes or until the flow slows down to just an occasional drip.

Clean off the oil drain hole with a paper towel or a rag and make sure the old washer is not still attached to the pan.

Spin in the drain plug a few turns by hand in the clockwise direction to make sure it doesn't become cross threaded.

Tighten the drain bolt in the clockwise direction with the 17mm socket and a 3/8" drive ratchet until it is snug.

If you have a sensitive and reliable torque wrench, the service manual torque specification for tightening the drain bolt is 23 to 30 lb-ft.

Old Oil Filter Location
Lisle Oil Filter Wrench
Loosen Counterclockwise
The oil filter is located just behind the oil pan.

Slide the used oil catch basin to just below the old oil filter.

Twist off the old oil filter by turning it in the counterclockwise direction.

If you have trouble removing the old oil filter that was over tightened at the factory or at a quick oil change station, I recommend using the Lisle 63600 oil filter wrench.

It makes loosening even the most stubborn and stuck on oil filters extremely easy.

Allow the old oil to drain out from the oil filter and the filter receptacle for at least a few minutes.

Dip Finger In New Oil
Lubricate Rubber O-Ring
Twist On New Oil Filter
Dip your finger into some new oil and lubricate the rubber o-ring gasket on the new oil filter.

Lubricating the rubber o-ring on the new filter will help it form a better seal, prevent oil leaks and also make it easier to remove during the next oil change.

Make sure the gasket from the old oil filter is not still attached to the engine.

Twist on the new oil filter in the clockwise direction until it is snug.

This should be about 1/3 to 1/2 turn past finger tight.

Try to avoid over tightening the new oil filter to prevent from damaging the rubber o-ring gasket which could lead to an oil leak.

Double check that the drain bolt and the new oil filter are tight before moving on to the next steps.

Line Up Access Cover
Slide In Front Edge
Re-Insert Pop Rivet
Slide the access cover back into place.

Make sure the pins in the center of the two pop rivets are in the raised and unlocked position.

Push In Center Button
Replace 2nd Pop Rivet
Pop In Center Pin - Lock
Push the two pop rivets back into place.

Pop in the buttons in the middle to lock the fasteners in place.

Tighten Clockwise
Replace Second Screw
Access Panel Secured
Replace the two screws by turning them in the clockwise direction with the 8mm socket and a 1/4" drive ratchet until they are snug.

Try to avoid over tightening the screws to prevent from damaging the plastic access cover or the skid plate.

Carefully lower the SUV from the jack stands by using the floor jack.

Insert Automotive Funnel
Pour In New Oil
Replace Oil Fill Cap
Insert the automotive funnel into the oil fill hole.

According to the owner's manual for the 2019 CX-9 the total oil capacity for an oil change with a filter replacement is 5.1 U.S. quarts (or 5.1 liters).

Since it is much better to have less oil than necessary in an engine than to overfill it, I recommend only pouring in about 4.5 to 4.75 U.S. quarts of SAE 5W-30 oil at first.

Running an engine that has been overfilled with oil may lead to sluggish performance and possibly cause damage to seals, gaskets or other components.

Temporarily replace the oil fill cap by twisting it on in the clockwise direction and push down the dipstick.

Push Down Dipstick
Check Dipstick Oil Level
Oil Change Complete
Start the engine and allow it to warm up for at least a few minutes to near operating temperature.

Turn off the ignition and allow the new oil to drain back down to the oil pan for at least 10 to 15 minutes.

Pull out the dipstick, wipe it clean with a paper towel, fully re-insert it and then pull it out again to check the oil level.

If necessary, slowly pour in more oil up to the 5.1 U.S. quarts total capacity for an oil change with a filter replacement and repeatedly check the level on the dipstick.

The correct oil level is when the oil on the tip of the dipstick reaches to or just below the upper hole.

Replace the dipstick and make sure that the oil fill cap is tight.

It would be a good idea to check your driveway, parking spot or garage for drops of fresh oil during the next few days which might indicate a leak from the drain bolt or filter.

To reset the oil life on the "maintenance monitor", follow these steps: 1. Select the "A" icon on the home screen to display the applications menu. 2. Select the "Vehicle Status Monitor" option. 3. Select the "Maintenance" option. 4. Switch the tab to the "Oil Change" option. 5. Press the "Reset" button to reset the oil life meter.

Turn off the ignition and turn it back on again but do not start the engine. You should see that the "wrench" icon is no longer being displayed.

Don't forget to write down the procedure in your vehicle's service records.

For more, please check out all of the 2016-2021 Mazda CX-9 DIY Repair & Maintenance Guides.

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