BMW E90 3 Series Buying Guide: What It Costs to Fix

What this guide covers

This guide covers the E90 sedan, E91 wagon, E92 coupe and E93 convertible with the N52, N51 and N54 engines named on our repair pages. The chassis page is BMW E90 repair costs. Costs are what owners reported; they are not failure rates, and a repair with few reports may simply be one owners talk about less.

Engine oil leaks

Look for a burning oil smell and oil on the serpentine belt. The valve cover is the common N52 leak, with seepage at the cover edge (Valve Cover / Valve Cover Gasket), and the oil filter housing gasket leaks on the N52 and N54 (Oil Filter Housing Gasket (OFHG)). The oil pan gasket is a bigger job on E9x cars (Oil Pan Gasket), and the rear main seal needs the transmission out (Rear Main Seal), so make sure the leak is diagnosed correctly.

For the engines, see BMW N52 Common Problems and Repair Costs and BMW N54 Common Problems and Repair Costs.

Cooling system

Ask about the electric water pump and thermostat (Electric Water Pump + Thermostat). The radiator leaks at the side tanks, and manual and automatic cars take different radiators (Radiator Replacement (E9x)). A sweet smell inside the cabin with foggy windows or a wet footwell points at the heater core, a labor-heavy job with book time of about ten hours (Heater Core Replacement). The A/C compressor (A/C Compressor (E9x)) and evaporator (A/C Evaporator Replacement) are the warm-air items.

Steering, suspension and bearings

Whining when turning and fluid at the reservoir means power steering hoses or pump (E90 Power Steering Hoses & Pump). A steering wheel shimmy under braking, wander at highway speed or a clunk over bumps points at the fluid-filled thrust arm bushings, which often wear by 40 to 60k miles (Front Control Arms & Thrust Arm Bushings). A hum that rises with speed is a wheel bearing (Front Wheel Bearing / Hub, Rear Wheel Bearing), and a clunk on takeoff is the driveshaft flex disc (Driveshaft Flex Disc (Guibo)).

Small repairs that add up

Check the engine mounts, which are fluid-filled and wear sooner on the 335i, but get a second opinion (Engine Mounts). Other items owners priced include the alternator (Alternator Replacement), starter (Starter Motor Replacement), door lock actuators (Door Lock Actuator), window regulators (Window Regulator (Cable Type)) and adaptive headlights (Adaptive Headlights / AHL Module). Clogged sunroof drains can send water into the cabin, and water damage to modules can dwarf the cleaning cost (Sunroof Drain Cleaning).

How to buy

Ask for service records that show which of the jobs above were done, check for coolant crust and oil on the belt area, and listen for the noises described. For M3 cars see the BMW E90/E92 M3 (S65) Buying Guide: Rod Bearings.