Second Hand Mercedes-Benz GLS Catalytic Converter

The GLS exists in two main generations: the X166 (2016–2019) and the X167 (2020 onwards), and the catalytic converter fitted depends heavily on the engine code and emissions standard (Euro 6 being the relevant era for both UK generations). Parts crossing the X166-to-X167 boundary are strong confirm-with-breaker territory, as the engine families and exhaust architectures changed between generations — a visually similar cat from the wrong generation may not fit or could cause MOT issues. Always confirm against your registration with the breaker before purchasing.

Yes, all petrol-engined GLS variants (including the straight-six and V8 units across both the X166 and X167 generations) are fitted with catalytic converters as part of the exhaust after-treatment system. Diesel GLS variants use a different after-treatment system centred on a diesel oxidation catalyst (DOC) and DPF rather than a traditional three-way catalytic converter, so what you need depends on whether your GLS is petrol or diesel. Make sure you know your fuel type and engine code before requesting quotes from a breaker.

These are different engine codes — the 350d uses the OM642 V6 diesel and the 400d uses the OM656 straight-six diesel — and the exhaust after-treatment components differ accordingly. On diesel variants the relevant parts are the diesel oxidation catalyst and DPF rather than a conventional catalytic converter, and interchange specifics between these two engines are strong confirm-with-breaker territory. Give the breaker your exact registration and engine code so they can check against their stock.

No — trim level (whether AMG Line, Grand Edition, or similar) does not affect catalytic converter fitment on the GLS. What matters is the engine code, fuel type (petrol or diesel), and the emissions standard the vehicle was built to, all of which are tied to the drivetrain rather than the trim specification. Your registration and engine code are all the breaker needs to identify the correct part.

These models use different engine codes — the GLS 500 (X166) used a 4.7-litre bi-turbo V8, while the GLS 580 (X167, from 2020) uses a 4.0-litre bi-turbo V8 with a mild-hybrid system — so the exhaust and emissions hardware differs between them. Whether any components interchange is strong confirm-with-breaker territory, particularly given the change in engine architecture and the addition of the 48V mild-hybrid system on the X167. Confirm against your exact registration and engine code with the breaker before buying.

A 2018 GLS sits in the X166 generation, while a 2020 GLS is an X167, and these are distinct vehicles with different engine families and exhaust systems despite sharing the GLS name. Whether any catalytic converter components cross this generation boundary is something you must confirm with the breaker against your specific registration and engine code, as a part from the wrong generation may not physically fit or may affect emissions compliance at MOT. A good breaker will check their stock against your reg to be sure.