BMW B48

The petrol four of the modular family — the same 500 cc-per-cylinder architecture as the B38 three and B58 six — and the N20's replacement across BMW and MINI.

It exists in this catalogue partly to be told apart from the N20, whose timing-chain reputation dominates any search for a BMW 2.0 turbo. The B48 addressed that area, and applying N20 expectations to it is the same category error as reading an N54 fault onto an N55.

It is a closed-deck design with an integrated exhaust manifold in the head, which is efficient but means cooling-system faults are less tolerable than on an older engine: the coolant path runs through the head casting, so an overheat has fewer places to be harmless. Direct injection brings the usual intake-valve carbon at higher mileage, mitigated on later versions by supplementary port injection. Because the family shares parts and behaviour across cylinder counts, a fault documented on a B58 often reads across directly.