Old filter on left, new filter on right - who knows when the filter was last changed. The car is currently 14 years old and has 145,000 miles.

Maintenance catch-up continued on my friend’s ‘03 WRX last Friday. Included in Friday’s work was investigating the cabin air filter. MonkeePuzzle informed me that some early GD/GG Imprezas were equipped with a cabin air filter, which was either a dealer or owner installed option. Apparently, this one was so equipped...

As it turns out, I wasn’t the only one unaware of the possible existence of a cabin air filter in this car... the filter that was in place was quite nasty!