Mercedes-Benz AMG C32 2001–2020 — technical service bulletin

Bulletin LI83.20-P-051802 · NHTSA communication 11017039 · issued Apr 1, 2025

Technical service bulletin

communication type

Engine

component

2001–2020

model years

vehicle entries

Official summary

Complaint Vehicle with atypical reduced heat output. Cause Silicate granulate may have escaped from a damaged bag in the expansion reservoir (not visible), reducing the coolant flow in the heater heat exchanger (see picture). Remedy With the aforementioned complaint, make sure that the cooling circuit is inspected for silicate residues after all standard tests are completed. The silicate residues tend to accumulate upstream of the shutoff valve for the heater hot water pulsed valve. If there are silicate residues in the coolant, the engine must be flushed thoroughly. To make sure that all sili

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.