DIY: BMW E39 5 Series Cabin Air Filter

How to replace cabin air microfilters on the BMW E39 5 Series (1997 - 2003)

Parts:

• Cabin Air Filters. Choose any of the brands below. I went with the Mann filters. 
• Mann CUK2736-2
• Bosch C3821WS
• Meyle 64112182533 (Charcoal activated)
• Meyle 64319069927 (Paper filter) 
• Mahle LAK 73/S

Recommended:

• Vacuum, towels, all purpose cleaner, Lysol or Einszett Klima AC cleaner. 

Steps:

• Pop open hood

• Locate two cabin filter service covers. One is located on the driver side and the other on the passenger side behind the strut towers. 

• Unclip wire latch circled in red below. Do this on both sides. 

A screwdriver may be used if it is difficult to unclip.

• Pull filter cover out towards you. Be careful not to damage the two rear plastic tabs. 
• Part # 64318379627 left and part # 64318379626 right in case they need to be replaced. 

• Remove old cabin air filters. 

Old micro filter.

• I don't think the previous owner ever changed the filters. Look at all the dusty, mold, and crap that on the old filter. Yuck! New Mann filter looks so much better. 

• Clean filter box by vacuuming leaves, wiping away any dirt and debris. Ensure intake and drain holes are clear. 
• Now is good time to spray any Lysol or A/C cleaner into the air box intake to remove nasty and funky smells. 

Previous owner never cleaned the box so there is dust and debris everywhere. 

• Install new filters by placing them in box. 
• There are directional air flow arrows on the Mann filter which tells you which side is up. 
• Many filters have less pleats than before and do not fit perfectly in the air box. There may be some gaps on the side and distortion. Unfortunately, I haven't found a brand that is a perfect fit. 

• Install covers by inserting rear tabs in first

• Reclip wire latches onto covers.

Notes: 

You want to replace the microfilters regularly to ensure pollen, dust, harmful gases, and spores are removed from the ventilation system. Spend the extra money and get the charcoal filters for optimal filtration. 

If you do not replace them, they will look as nasty as the old filters and you will be breathing all that crap. This is a 5 minute job and the filters are cheap, just do it yourself. A mechanic will charge too much to replace the filters and may not remove the debris hanging out in the box. 

The filters come in pairs.

Helpful picture below. Taken from BMW Parts manual.

Here is a Top Gear clip of Jeremy Clarkson banging on the cabin air box with a hammer. Jeremy thinks it is a fuse box and Richard and James correct him.

Why: 
Microfilters clean the air in the cabin of your BMW. A dirty and clogged microfilter means you and your passengers are breathing in that polluted air. Microfilters remove contaminants, pollen, pollutants from the air going into the cabin. This is the quickest and easiest jobs you can do and I am shocked that the previous owner never changed them. 

DIY: Infiniti QX4 & Pathfinder Air Filter 2001-2003

How to remove and reinstall engine air filter for the Infiniti QX4 & Nissan Pathfinder R50

May apply to earlier model years. 

Steps:
Pop open the hood and locate the engine air filter box. The box is behind the driver side head light assembly.

Locate the clips and pop them open. Pull the tray holding the air filter out. Clips are highlighted in red.

Remove the air filter and put in the new one. The filter goes in one way with the rubber seal facing the driver.

 

Dirty air filter removed. 

 

Dirty and clean filter comparison.

Check your filter with every oil change and see if it is dirty and clogged. A dirty air filter results in lower performance and MPG loss. Changing the filter is super quick and a cheap way of making sure you get the most performance out of your car. 

K&N 33-2031-2 High Performance Replacement Air Filter is the best air filter you can buy. The K&N Air Filter can be cleaned and re-used which saves a lot of money in the long run.

Purolator PA24278 PureONE Air Filter is pretty good if you don't want a re-usable filter.