Exhaust fumes inside the cabin, VW T6 TDI (Solution)

When there's a smell of exhaust fumes inside a VW T6 with a TDI engine, the EGR pipes are prime suspects in the investigation of the cause.

The AGR pipes can either tear at the corrugated sections or directly at the flange. The cracks can be identified by slight traces of soot, hissing sounds under load, and the smell of exhaust fumes when the vehicle is stationary.

The AGR pipe at the front is relatively easy to replace, but accessing the one at the back, near the turbocharger, requires a lift.
A 1/4" ratchet with a swivel head and a short extension is useful for the screws on the turbocharger.

Generally, extensions are very helpful because you often need very long arms, or the workspace is somewhat limited.

Part number for the front AGR pipe:
04L131521AR

Part numbers for the rear AGR pipe:
04L131521BF
or
04L131521BH

"Which of the two is correct must be verified with the dealer using the VIN."

For my 2018 150HP TDI, the part number was 04L 131 521 BH. The corresponding seals are 04L 131 547 S and 03L 131 547 P.