How to replace air filter on a 2015 Subaru Forester

DIY: Remove or replace the air filter on a 2015 Subaru Forester

Tools required: 
None
Screwdriver if removing intake boot (optional)

Time: 
5-10 minutes

Car: 
2015 Subaru Forester 2.5i


Steps: 

• Open the hood.
• Locate Air Filter Box on passenger side behind headlight.
• Remove two metal clips holding two halves of air filter box together. Clips are circled in red below. 
• Push the rear half of air box backwards and remove dirty air filter. 
• If there is not enough space to remove the old filter, consider removing the rear half. Loosen and remove the clamp circled below in blue and pull the intake hose backwards. Un-clip the MAF sensor wire bundle and remove the rear half.

 

•  Dirty OEM air filter below. 

 

• I replaced the old filter with a MAHLE Air Filter. The Mahle filter has more pleats for better filtration and performance. Look at the picture below to see the difference. 

  Installation:

• Install new filter with the pleats facing the headlights and flat side facing passenger. If there is excessive dirt and grime, clean the area with soapy water or a degreaser. 
• Push rear half to forward half until they fit and re-attach two metal clips. 
• If you removed the rear half, attach the rear half and MAF wiring bundle. Connect intake hose to rear half and reattach clamp. 
• That's it! 

Start the car and check for major air leaks around the air box halves and intake hose.

Notes: 
Check your air filter at least every other oil change. Air filters typically need to be replaced 10,000 - 15,000 miles depending on driving habits and air quality.

A clean air filter will improve gas mileage and power. Do not let a dirty air filter punish you at the fuel pump.

DIY: Clean or Replace MAF Sensor on R50 Pathfinder or QX4

Steps: 

-Remove the 10mm nuts and bolts securing the air box filter. Red Arrows
-Remove the two plastic hoses on top of the air box. One of the hoses attaches to a metal nipple at the end of the air box. Blue Arrows.
-Loosen the MAF clamp with a Phillips screwdriver. 

-Remove the four 10mm bolts holding the MAF to the rear of the air box. Red Circles.
-One of the plastic tubes on top of the air box plugs into the metal nipple circled in blue. It may be difficult to remove the tube and will take some time. Be careful not to bend or clamp the metal nipple.

-Remove the electrical plug from the MAF sensor. Circled in Red.

-Remove the air box assembly and then remove the MAF. I had difficulty removing the MAF without taking out the air box assembly. I was worried about damaging the intake boot which is why I removed the air box assembly first.

-Once the MAF is removed, you can take out the sensor by removing the two bolts holding it into place. Red Arrow.

-Use CRC 05110 Mass Air Flow Sensor Cleaner - 11 Wt Oz. to clean the MAF sensor. Do not touch the sensor or wipe it with a towel, let it air dry. Spray the cleaner directly onto the sensor highlighted in green.

Installation is the reverse of removal. Pretty simple.

I suggest using Super Lube 21030 Synthetic Grease (NLGI 2), 3 oz Tube on the hose that attaches to the back of the air box for easier installation and removal.

Now is also a good time to replace the air filter if it is dirty and clogged. I use K&N 33-2031-2 High Performance Replacement Air Filter because of its high performance and re-usability.

Why clean your MAF sensor? 
Dirty MAF sensor results in poor gas mileage, loss of power, difficulty starting, engine stalling, and lean or rich idling. If the MAF sensor is extremely dirty, you may get a check engine light.

Take the time to clean your MAF sensor on a periodic basis, it only takes a short amount of time and will save you money at the pump.

Note:
If the mass air flow sensor meter is cracked or warped, you need to replace it. I recommend buying this one.

If the sensor itself is damaged and cleaning does your fix your issues, you need to buy a new sensor. I recommend the Delphi AF10163