Engine knock on BMW: causes by model and engine

Documented faults, from most to least important

Severity × frequency. Below each one, the BMW models it appears in.

- Critical severityFrequency: Very frequentBMW N47Rear timing chain stretch and breakageYes: the N47 has its timing chain at the rear of the engine, next to the gearbox, and on a very high proportion of units, especially those built between 2007 and 2009, it stretches or breaks prematurely because of an inadequate tensioner, with a risk of destroying the engine.Repair (garage): €1,590–€3,000Appears at around 50,000 km
In Serie 1 E87, Serie 1 F20, Serie 3 E90, Serie 3 F30, Serie 5 E60 and Serie 5 F10 and 3 more models
- Critical severityFrequency: Very frequentBMW M47Intake swirl flap breakage (swirl flaps)Yes: the common rail versions of the M47 (built since 2001) have flaps in the intake manifold that, with diesel soot and heat cycles, can break and be sucked into the cylinder, with a risk of serious damage to the piston, cylinder head and valves.
In Serie 1 E87, Serie 3 E46, Serie 3 E90, Serie 5 E60 and X3 E83
- Critical severityFrequency: CommonBMW N43/N46Wear and breakage of the timing chain guidesYes: both the N43 and the N46 can stretch the timing chain and wear its plastic guides and tensioner. On the N43, English-language Wikipedia documents that a broken guide can release fragments that block the oil strainer and cause serious damage through lack of lubrication.
In Serie 1 E87, Serie 3 E90, Serie 5 E60, X1 E84 and Z4 E85/E86
- Low severityFrequency: OccasionalBMW N52 / N53N52 hydraulic lifter noiseN52 engines from before December 2008 can have hydraulic lifters that make a tapping noise when cold because of a lubrication problem.
In Serie 1 E87, Serie 3 E90, Serie 5 E60, X3 E83, X5 E70 and Z4 E85/E86

By BMW model

Open yours to see only the faults that affect it, by engine and by year.

Engines and gearboxes involved

Frequently asked questions

Engine knock in a BMW: what could it be?

In 12 models from BMW there are 4 documented faults that cause this symptom (engine knock). The most important: rear timing chain stretch and breakage, intake swirl flap breakage (swirl flaps) and wear and breakage of the timing chain guides. Each fault has its own page with the affected years and versions, the cause and how to check for it.

Which BMW models have the most faults with this symptom?

BMW Serie 5 E60 (4 faults), BMW Serie 1 E87 (4 faults), BMW Serie 3 E90 (4 faults) and BMW X3 E83 (3 faults).

Which BMW engines cause it?

BMW M47 (1 fault), BMW N43/N46 (1 fault), BMW N47 (1 fault) and BMW N52 / N53 (1 fault).