VW TDIs are turbocharged engines with precise air metering. This means that the intake air has to be clean to protect the turbo and Mass Airflow Sensor. It also helps to keep moisture out of the air system where possible. And the airbox on a TDI should seal well to protect both against dirt and innacurate Mass Airflow readings.

Even though most folks agree that the manufacturer’s recommended 10,000 mile oil change interval is the way to go, there’s lots of debate regarding how often to replace the air and fuel filters in TDIs, especially CBEAs. Some people change air filters as often as every 10,000 miles, but most feel every 20,000 miles is a good interval. Whatever change interval you choose, the filter change is quick and easy. Here’s how to do it.

What will you need?

Air filter, part number 1K0 129 620 or 620A. The difference between these two filters is the number ending in the letter A includes a pre-filter. CBEA engines have a two part airbox that can draw air from inside the engine compartment if the snorkel to the outside is blocked. The prefilter helps keep moisture out of the engine when the airbox is accessing air from the engine compartment.

Many people decide to save a few dollars and forgo the prefilter. Whether or not you use one is up to you. However, we believe that all CBEA TDIs in North America were delivered with pre-filters. It’s your choice.

All you’ll need is a Phillips head screwdriver for this swap. Easy.

Changing the filter

There are a total of six screws on the top of the air filter box, four on the filter and two on the MAF connector. Remove the four airbox screws

Then remove the two screws on the MAF connector.

You can see all six screws in this top down view

Once the screws are out, lift the cover and remove the filter. Here you can see the old (20K) and new filters side-by-side.

If you look at the dirty filter you can see the line made by the partition in the airbox.

Put the new filter in place. It should fit snugly. Press the cover into place and replace the screws. You’re done!

A final note

Folks sometimes like to open their airbox to take a look at their filter to see if it’s time for replacement. This isn’t a good idea. Manufacturers maintain that the gasket on the filter is designed to seal—once. Technically, if you open the box you should replace the filter as it won’t seal as well the second time.