TDI engine intake and cabin air filter replacement

Changing the engine intake or cabin air filter
Difficulty: 1/5
Back to a4 "how to" index

Introduction

This article is divided into three sections: replacing the intake air filter, cleaning the snowscreen, and replacing the cabin air filter. The snowscreen is an air intake snorkel with a screen that keeps out large debris and snow out of the air intake box. If it gets clogged with mouse nests or leaves, a spring loaded auxiliary intake flap opens, preventing the engine from air starvation. This air is warm engine bay air and is not as good as cold intake air but it prevents the engine from stalling.

Mann makes the OEM VW air filter so it's a good filter. The cold climate air filter has an extra foam layer on the bottom.

Parts (click links to compare current prices)

1 new air filter - either:
Cold climate engine air filter (with extra foam layer) VW# 1J0 129 620 -a genuine VW, mann filter, german filter
Non cold climate engine air filter VW# 1J0 129 620 genuine VW, mann filter,
phillips screwdriver
a brush or compressed air to blow out screen.

Procedure

Intake air filter replacement

All you have to do is unscrew the top cover.
(2 phillips screws). Mine were rusty so I used a dremel to cut a groove in them and then used a standard screwdriver to remove the screws.

If you need more clearance, remove the MAF electrical plug and unclamp the accordion like hose if you want. I also suggest vacuuming out the bottom of the air filter box and cleaning the snowscreen while you are in there. Make sure the tabs all fit into their slots and that the air filter edge gasket is seated properly.

These cars are known for slow MAF failure. If your car has been losing power, a faulty MAF may be responsible, see 1000q: limp mode, 1000q: constant low power or can't rev, and 1000q: a4 MAF for more details. If you determine that the MAF is bad and need to remove the element, a special VW tool is required to remove the MAF screws. You could also use the dremel to cut a groove into it and just replace them with normal screws. Most MAF come as a whole unit and requires no special tools to remove.

Very easy but here's a video anyways. There's unnecessary music in the video so don't bother turning up the volume.

Cleaning the snowscreen

Note that in the below pictures, the air box and battery were removed for clarity.

Remove (1x 10mm) nut circled in yellow and pull out the intake snorkel. The snowscreen is at the end. Just use water or compressed air to clean it out and then replace it. I do not recommend cutting the snowscreen out since it prevents larger debris from reaching the air filter.

Here is the spring loaded door.

Cabin air filter

Remove the 4 phillips screws (one is circled in red) and pull up and away the rubber weather stripping on top of the firewall.

Pull out the plastic trim and the cabin air filter. During reassembly, the black plastic frame has 2 tabs on the top front edge and 3 tabs on the lower rear edge. 1 of the tabs is marked in red.

Vacuum out any dust dirt from around the area and replace the filter and trim. The ribbed cylindrical object below the air filter is the blower fan.

I prefer activated carbon filters since the activated carbon absorbs and removes odor from the air.

We would like to hear your story or tips so feel free to share in the myturbodiesel.com forums