What to watch for on the BMW 3 Series

People buy the 3 Series BMW for the rear-wheel drive, the steering and the strong engines. Used, it is often priced close to an Octavia, but the running costs can be elsewhere. That is why with the 3 Series it pays to choose by engine and history, not by equipment. This is a general overview of what owners talk about most. It is no substitute for fault statistics, it serves as a basis for questions to the seller. Always check a specific car against the pre-purchase checklist, ideally at a garage that knows BMWs.

Generations. E46 (1998–2006), E90/E91/E92/E93 (2005–2013 depending on the body), F30/F31 (2012–2019) and G20/G21 (from 2019).

Diesels.

• The four-cylinder N47 (mainly 318d, 320d, roughly 2007–2014) has timing chain problems on some engines. The chain sits at the back of the engine, so replacement is expensive. Listen to a cold start, a rattle from the gearbox end is a warning. Ask whether the chain has been replaced and ask for the invoice.
• The newer four-cylinder B47 (from 2014) and the six-cylinder N57 are rated better.
• For all diesels the usual applies: particulate filter, EGR valve, swirl flaps in the intake on older engines, turbo and dual-mass flywheel.

Petrol engines.

• The four-cylinder N20 (F30, roughly 2011–2015) has timing chain guide problems on some engines. Again, listen to a cold start and ask about the history.
• The six-cylinder N52 and N53 (E90) are popular. On older ones the electric water pump, thermostat and oil leaks come up. On the direct-injection N43 and N53 there are injector and ignition problems.
• The turbocharged six-cylinder N54 (335i) has high-pressure fuel pump and turbo problems on some cars. The newer N55 and B58 are considered more robust.

Oil leaks. On many BMW engines the valve cover gasket or the oil filter housing gasket starts to leak over time. Look under the engine and along its sides. A slight film of oil is not a disaster, but oil dripping onto the exhaust or the belt is a problem.

Gearboxes and drive. The six-speed and eight-speed ZF automatics tend to be reliable if the oil has been changed, even though the manufacturer calls it "lifetime" fill on some generations. On xDrive (all-wheel drive) listen when turning in a car park for clicking or scraping, which can point to a problem with the transfer case.

Suspension and tyres. Many 3 Series run on run-flat tyres, which are harder and dearer. Check the tyre wear and the condition of the arms and bushes on the front axle. Rear-wheel drive, power and "sporty" previous owners mean it pays to look at the differential and clutch too.

Electronics. Try iDrive, navigation, air conditioning, parking sensors and lights. A warning light or an error on the display can be minor, but also an expensive repair, so diagnostics are worth it.

History and mileage. Many 3 Series are imported. Check the service history and accidents by VIN and compare the mileage with the wear on the driver's seat and steering wheel.

Current offer and prices. The page Used BMW 3 Series shows how many 3 Series are on offer and for how much. You find the price development in Price trends.

Do you drive a 3 Series? Write the generation, engine, gearbox and mileage and what you repaired. Experiences with the chain on the N47 and N20 and with running costs will be appreciated by anyone thinking about a BMW.