BMW · 2005–2019
Common BMW 3 Series problems, and how to check them
These are the 2 faults owners and garages report most often on the BMW 3 Series, from the most common down. For each one: what goes wrong, how to check it yourself, and the usual fix, so you know what you’re dealing with before you buy parts.
Checked and updated 27 September 2026
Problem 1
N47 timing chain failure (chain at the gearbox end)
What goes wrong
The N47 timing chain sits at the back of the engine and wears or snaps, often from 100,000-150,000 km; when it breaks the engine is usually wrecked.
How to check it yourself
Listen for a rattle or whine from the gearbox end of the engine, especially on a cold start or when lifting off at around 2,000 rpm. A garage can check chain wear with the engine partly dismantled.
The usual fix
Replace chain, guides, tensioner, and sprockets (a gearbox-out or engine-out job). Many owners do it preventively; check whether BMW goodwill applies.
Signs: Rattle on cold start, Check engine light
Fault codes: P0016, P0335, P0340
Problem 2
Oil leaks from the oil filter housing or valve cover gasket
What goes wrong
The oil filter housing and valve cover gaskets harden with heat. Oil can then reach the drive belt (which it can destroy) or, on the N20, the eccentric-shaft sensor and connectors, causing rough running.
How to check it yourself
Look for oil on the side of the engine below the oil filter housing and around the valve cover, and a burning smell after driving. Check the drive belt for oil and fraying.
The usual fix
Replace the leaking gasket and clean the area; replace an oil-soaked drive belt promptly (a shredded belt can be pulled into the front engine seal).
Signs: Oil leak, Rough idle, Stalling
Fault codes: P1014, P1015
General guidance, not a professional inspection. Confirm faults with measurements before buying parts, and use a qualified mechanic for brakes, steering, fuel leaks, airbags, and other safety-critical work. Terms and disclaimer