BMW M240i G42

The B58 oil filter housing module uses a plastic coolant vent hose and rubber gaskets that become brittle from heat cycles. Symptoms include a sweet coolant smell, declining coolant level, and white crystalline residue near the filter housing. Most G42 cars are still too young to show this, but the design is identical to the F20 M140i and F22 M240i, where the issue typically appears between 80,000 and 120,000 km. A permanent repair replaces the full OFHG set, plastic vent hose, and single-use aluminum bolts simultaneously. Independent specialist cost is €600-900; BMW dealers charge €1,000-1,500. A class action lawsuit was filed against BMW in early 2026 over this issue across B46/B48/B58 engines.

On the updated B58TU1 fitted to the G42 M240i, the PCV diaphragm is integrated into the valve cover rather than being a separate part. When the diaphragm tears, the entire valve cover assembly must be replaced rather than just a gasket. Symptoms include blue/white exhaust smoke, increased oil consumption, rough idle, and occasionally limp mode. BMW issued a warranty extension (SIB 01 14 23) covering the PCV valve cover for 15 years/240,000 km from the original in-service date, which applies to most G42 cars. Outside warranty, full valve cover replacement at a dealer costs €800-1,200 including labor. Aftermarket diaphragm-only repair kits are not viable on the integrated TU1 design.

Affects 2024 production M240i and other G-series models. The steering gear bolts may not have been tightened to the correct torque, allowing the gear to loosen during operation. This recall was issued in January 2024 and BMW replaces the steering gear free of charge. Verify the recall has been completed before purchase by checking with a BMW dealer using the VIN. If not yet done, the work is free under recall but the car should not be driven hard until it has been actioned. Symptoms include steering vagueness, knocking from the steering column, or wandering at speed.

The VANOS solenoid O-rings are a wear point on all B58 engines. The rubber hardens with age and oil contact, allowing oil to seep past, which triggers VANOS fault codes, rough idle, and reduced performance. Typically appears after 80,000-100,000 km. Solenoids cost €80-100 each and replacement takes around 30 minutes per side. Professional repair runs €200-500. Many owners report this as a straightforward DIY fix on the B58.

Like other modern BMW engines, the B58 uses an electric water pump. Some failures have been reported on B58 applications before 80,000 km, though it is not a widespread G42-specific issue. Symptoms include intermittent overheating warnings, coolant temperature spikes, or limp mode. Replacement cost is €500-800 at independents and €900-1,200 at BMW dealers, including coolant and a new thermostat which is recommended at the same time. The pump is buried at the front of the engine, so labor is the main cost.

The G42 uses iDrive 8 which has had a rocky early life. Owner reports include unresponsive touchscreens, restricted driver assistance warnings (lane keep, heated steering), and the digital key not always being recognized. Most issues are resolved by software updates, which BMW provides over-the-air or at the dealer free of charge during warranty. Outside warranty, dealer diagnostic and software work runs €100-300. Hardware replacement of the head unit, if needed, can reach €700-800. Also affected: the 2023 ECU recall that allowed windows and sunroof to operate after the digital key was removed.

Some G42 owners have reported internal condensation in the driver-side headlight unit. Light condensation often clears with use, but persistent moisture indicates a seal failure. Under warranty, BMW replaces the headlight unit free of charge. Outside warranty, a new LED headlight unit costs €1,000-1,500 including labor. Check both headlights carefully on a viewing, especially after rain or a car wash.