Engines · BMW
BMW M47 diesel common problems
The M47 is BMW's 2.0 four-cylinder turbodiesel, built from 1998 to 2007, with common-rail injection in BMWs from the 2001 update (M47TU) and more power from the 2004 update (M47TU2). It powered the 318d, 320d, 520d, 118d, 120d and X3 2.0d before the N47 replaced it, and a version was also used in the Rover 75, MG ZT and first Land Rover Freelander. It is well regarded and rewards regular oil changes.
Common problems and what to look for on the M47
The known issues most worth checking when you view a car with this engine. None of them means a car is a bad buy, but they're worth knowing about before you buy, and a good history often shows they've been dealt with.
Swirl flaps in the inlet manifold
What to look for: Ask whether the swirl flaps have been removed and blanked off, or replaced, and look for the invoice. A sudden misfire, heavy smoke or a loss of power on the drive are the signs that something has already gone wrong.
Why it matters: From the 2001 update the M47 has small flaps in the inlet ports. The screws holding them can loosen over time, and a flap or screw drawn into the engine can damage the piston, valves and cylinder head, and sometimes the turbo. BMW fitted larger spindles and screws from 2004 and plastic flaps from around 2006, but later engines can still fail. Specialists usually remove the flaps and fit blanking plates. A car with the flaps removed or replaced is in a good position.
Crankcase breather
What to look for: Ask when the crankcase breather was last renewed and look for it in the service history. Look for oily residue around the inlet pipework and the turbo, and note any smoke on the drive.
Why it matters: Specialists advise renewing the breather unit about every 40,000 miles, alongside regular oil changes. It's a routine service item, and a record of it is a good sign of a car that's been looked after.
Turbo and its oil feed
What to look for: On the drive, listen for a whistle or siren-like noise as the turbo boosts, and note any lack of power or blue or black smoke under acceleration. Ask whether the turbo or its oil feed pipe has been replaced.
Why it matters: Turbo failures are common on these diesels, often because the oil feed pipe to the turbo becomes blocked over time and starves it of oil. Regular oil changes help. Replacing the turbo, or fitting a reconditioned centre cartridge, is a known job, and specialists usually replace the feed pipe at the same time.
More known issues, covered in the full guide for each car
- Confirm it's the M47 and not the N47
Cars with the M47
- BMW 3 Series E46: 318d and 320d (150PS from 2001)
- BMW 5 Series E39: 520d, 2000 on
- BMW 5 Series E60/E61: 520d (163PS), 2005 to 2007
- BMW 1 Series E81/E82/E87/E88: 118d and 120d, 2004 to 2007
- BMW 3 Series E90/E91/E92/E93: 318d and 320d, 2005 to 2007
- BMW X3 E83: 2.0d, before the switch to the N47
A pre-purchase inspection guide for your car
The CrankSight guide is a pre-purchase inspection (PPI) you do yourself, written for the exact model and generation you're viewing. It walks you round the car on your phone, with every check for that version, engine included: what to look for, where to find it, and what anything you find is likely to cost. As you go it builds an assessment of that car, and if you view more than one, it lines them up side by side.
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General points for the engine, last checked October 2026. Every car is different, so treat this as a guide to what to look at, not a verdict on any car. CrankSight is independent and has no connection with any manufacturer.