M50/M52 vs S58
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."
S58
"The 3.0-litre twin-turbo straight-six of the X3 M, X4 M, M3, M4 and M2 (2019 onwards). So far it has proved very tough: AUTO BILD stripped a 100,000 km M3 and found almost no wear, no oil use and no breakdowns. The one manufacturing fault was a batch of main bearing shells in cars built July-September 2021, held back by BMW and repaired before delivery. Otherwise expect normal M-car wear items: crankcase ventilation valve, coolant leaks and spark plugs on hard-driven or tuned cars."