M260 (DE20LA) vs M104
Side-by-side reliability comparison
Specifications
Character
M260 (DE20LA)
"The transverse 2.0 turbo petrol in the A 220/A 250, B 250, CLA 250, GLA 250, GLB 250 and the AMG 35 models from 2018. German guides call it robust. Its known weak point is wear of the exhaust valve seats and guides: Mercedes extended the warranty in North America to 15 years / 150,000 miles and the fix is a new cylinder head. Check for misfire codes and ask whether the head has been replaced."
M104
"Twin-cam 24-valve straight-six of the W124, W140, R129, early W202 and W210. The block and bottom end are long-lived - 400,000 km and more are documented. Two things to check: the engine wiring harness on cars built about 1993-1995, whose insulation crumbles (a new, later-type harness is the permanent fix), and the head gasket, which can weep or blow with age, usually after overheating, so the cooling system and fan clutch must be healthy."