The dealer-entry of 'CL Class' looks like a likely typo — the four-door coupe sold in 2018 is the CLS, not the old CL. Also, Mercedes large coupes of this era almost always came with automatic gearboxes, so a factory-fitted diesel manual is uncommon; verify the VIN/ID plate to confirm the exact model and transmission. Diesel engines on these cars often have DPF/EGR and sometimes AdBlue systems, so history of motorway use and regeneration events matters; servicing at dealers is pricier, but competent independent Mercedes specialists are common in Ireland.

• Confirm model and transmission via VIN/ID plate and paperwork — ensure it really is the CLS and that the manual gearbox is factory-fitted, not a mis-specified listing.
• Clutch and gearbox: test for slipping, a heavy or grabbing pedal, smooth gear engagement and no crunching or synchro noise during row-up/row-down shifts.
• DPF / EGR / AdBlue: check for warning messages, evidence of frequent DPF regens or a blocked DPF (black smoke, limp mode) and AdBlue fault codes if the car is SCR-equipped.
• Air suspension (if fitted): check ride height both sides, listen for compressor runs or leaks, and look for suspension error warnings — repairs are expensive.
• Boot access and rear comfort: check rear headroom and boot seals/hinges for leaks or wear caused by the coupe roofline and heavier use of the load area.