Is the B58 reliable?

Widely regarded as one of BMW's most reliable modern engines.

Most weak points are known and fixable: coolant tank and pump leaks; a plastic oil filter housing that can leak coolant or oil, often from about 60,000 miles, the subject of a proposed 2026 class action covering 2014 to 2021 X3, X4 and 1 to 5 Series cars; a crankcase ventilation valve whose diaphragm can split, which BMW covers for 15 years or 150,000 miles on the first engine (SI B01 14 23, cars such as the 2017 to 2021 M240i and 2018 to 2019 X3 M40i); and carbon on the intake valves of the direct-injection-only engines, before the 2025 update added port injection.

One is not: on engines built from about 2018 to 2022, the variable oil pump's plastic ring can crack, and complaints cluster on 2020 and 2021 M340i cars; BMW changed to a metal part during 2022. Well-maintained engines are widely reported to pass 150,000 miles; no measured figure exists.

Reliability is each car's score out of 100 for the years it had this engine: the engine rating plus that car's own known problems, service costs and age. The Guide Score is for the car's best year to buy.

Bills are the guides' estimates, not quotes; each car's guide says which model years a problem hits and how to check for it. The bars share one scale, up to the costliest bill here.

Every engine we rate, from the most reliable down, is on the engines page.