Audi A4 1998–2005 — technical service bulletin
Bulletin 0406 · NHTSA communication 10011880 · issued Dec 13, 2004
Technical service bulletin
communication type
Engine and Engine Cooling
component
1998–2005
model years
16
vehicle entries
Official summary
Coolant leak at oil cooler hoses. *tt
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.