Second Hand Mercedes-Benz GLS EGR Valve

It depends on the engine. Diesel variants of the GLS — including the GLS 350d — do have an EGR valve as part of their exhaust gas recirculation system, which is standard on diesel engines to meet emissions targets. However, the petrol-engined GLS variants (such as the GLS 400, GLS 500, and GLS 63 AMG) do not use EGR valves, so if you have a petrol GLS you will not find this part on your vehicle. Check your V5C or registration plate against the engine code to confirm which you have before searching.

These are distinct generations with different engine architectures, so the EGR valve from an X166 GLS is very unlikely to be compatible with an X167 GLS even if the engine displacement looks similar on paper. The X166 ran from around 2016 to 2019 and the X167 was introduced from 2019 onwards, and Mercedes updated engine internals and emissions hardware between the two generations. You should always confirm the exact engine code with the breaker against your registration to be sure.

No — trim level does not affect EGR valve fitment on the GLS. Whether your GLS is in AMG Line, AMG Line Premium, or any other trim designation, the EGR valve is determined entirely by the engine code and the emissions standard the vehicle was built to, not by how the car is specced or badged. Give the breaker your engine code (found on the V5C or stamped in the engine bay) and your registration, and they can match the correct part.

Both of these fall within the first-generation GLS (X166) range, and if they share the same engine code the EGR valve is likely to be compatible, but you should still confirm with the breaker against both registrations. Minor running changes and emissions-related updates can occur within the same model year range without a formal facelift, so an identical engine code is the key check rather than the model year alone. Never assume fitment without the breaker verifying both vehicles' codes.

Yes, this matters and is worth checking carefully. The EGR system is directly tied to the emissions hardware of the vehicle, and a valve from a Euro 5 engine may not function correctly or may cause emissions faults if fitted to a Euro 6 engine, even with the same displacement. The Mercedes GLS was introduced to the UK in 2016, by which point Euro 6 was the prevailing standard for new vehicles, but always confirm the exact emissions classification of the donor vehicle with the breaker against your registration to ensure you are getting a like-for-like unit.

The GLS was effectively the successor to the GL-Class, and some engine codes were shared across the Mercedes SUV range, so there is a possibility of crossover — but this is not something to assume. Engine codes must match exactly, and the emissions era of the donor vehicle needs to align with yours. Confirm with the breaker using your full registration and engine code, as fitting a valve from a different model or era could cause running issues or an MOT failure.