M50/M52 vs M43
Side-by-side reliability comparison
Specifications
Character
M50/M52
"Smooth, linear inline-six with bulletproof internals — 300,000 km is routine. Budget a full cooling-system refresh (plastic tank, impeller, thermostat housing) and expect VANOS seals and the oil separator to need doing. Only trap: European M52 built 1995 to early 1998 had Nikasil bores that sulphur fuel destroyed; ask for a leak-down test or proof of a replacement block. M50 and M52TU are not affected."
M43
"BMW's simple 8-valve four-cylinder (1993-2002): M43B16 and M43B18 in the E36 316i/318i, E34 518i and Z3, and the M43TU 1.9 with balancer shafts in the E46 316i/318i and Z3 1.9. Iron block and a timing chain instead of the M40's belt. German guides call it robust, unlike the N42/N46 that replaced it. Typical age faults only: cooling-system plastics, oil leaks from the valve cover and front cover, noisy hydraulic lifters, the DISA intake valve and, on older cars, the air-flow meter."