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BMW N47 (N47D20 / N47C16 / N47C20)Urgency: As soon as possible

Deep metallic engine knock in the BMW N47 engine: causes

In the BMW N47 engine, 1 documented fault may be the cause: rear timing chain stretch and breakage.[1]

What to do now

As soon as possible

Switch the engine off and do not drive on. Carrying on can snap a connecting rod and leave the engine beyond repair.

What it means

A deep knock that gets louder with engine speed usually points to internal damage, such as big-end bearings worn through lack of lubrication. It is one of the most serious faults an engine can have.

Engine knock: causes in all cars

9 sourcesHow we work

Engine faults that cause it

From most to least important. Under each fault, how the symptom shows up. Check the affected years and versions on each page.

  1. Source for the symptom[1]

How much it can cost

Depending on the cause, repair at an independent garage ranges from €1,590[2][3][4][5][6] (rear timing chain stretch and breakage) to €3,000[2][3][4][5][6] (rear timing chain stretch and breakage), including VAT.

Most serious fault among the possible causes: Critical severity

Other common causes: engine knock

Besides the documented faults of the BMW N47, these are the most common causes on any car according to the sources.

  • Play in the big-end or main bearings (rod knock)[7][8]Common
  • Lack of lubrication: low or degraded oil or insufficient pressure[8][9]Common
  • Stretched timing chain or tensioner without pressure[1][7][8]Possible
  • Hydraulic tappets and valves with play[7][8]Possible
  • Worn pistons and rings[8]Uncommon
  • Normal diesel engine noise[8]Possible

What to check first

  1. Stop the engine as soon as it is safe and check the oil level with the dipstick on level ground and with the engine cold or stopped for a few minutes; it is the first step recommended by Todoaditivos and RACE.[7][9]
  2. Look at the oil pressure warning light (red): if it is on along with the knocking, don't start the engine again and call assistance.[7][9]
  3. Note when it makes the noise: only when cold and for a few seconds (probably tappets or tensioner), or with the engine warm and growing with load and revs (much more serious).[7][8]
  4. Look for oil leaks on the ground or blue smoke, signs that the engine is losing or burning oil, according to RACE.[9]
Complete guide: deep metallic engine knock

Cars with the BMW N47 engine

Open yours to see only the faults that affect it according to its years and versions.

Frequently asked questions

Engine knock in the BMW N47: what could it be?

In the BMW N47 engine, 1 documented fault may be the cause: rear timing chain stretch and breakage. Each fault has its own page with the affected years and versions, the cause and how to check for it.

Engine knock in the BMW N47: is it serious?

Urgency: as soon as possible. Switch the engine off and do not drive on. Carrying on can snap a connecting rod and leave the engine beyond repair. The most serious fault that causes it on this engine has critical severity.

Engine knock in the BMW N47: how much does it cost to fix?

It depends on the cause: at an independent garage, from €1,590 (rear timing chain stretch and breakage) to €3,000 (rear timing chain stretch and breakage), including VAT.

Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. Las graves (y costosas) averías que puede causar en tu coche la rotura de la cadena de distribuciónDiariomotor · Motoring press · consulted 26 September 2026 · in Spanish
  2. Motor N47 - precio cambio cadena BMWTaller Barcelona (Dasercars) · Technical documentation · consulted 26 September 2026 · in Spanish
  3. Precio sustitución cadenas motor N47 BMW MINIArroyo Auto, Especialista BMW MINI · Technical documentation · consulted 26 September 2026 · in Spanish
  4. Motor BMW N47 - Reparación EspecializadaDasercars · Technical documentation · consulted 26 September 2026 · in Spanish
  5. Rotura cadena distribución y rotura motor N47OCU · Consumer association · published 2 September 2021 · consulted 26 September 2026 · in Spanish
  6. Problema cadena BMW motor N47, qué hacer y solucionesRecomotor Blog · Motoring press · consulted 26 September 2026 · in Spanish
  7. El motor hace ruido en frío: qué es cada ruido y cuál preocupaTodoaditivos · Other source · consulted 29 October 2026 · in Spanish
  8. ¿El motor diésel de tu coche emite un ruido y un traqueteo?RACE · Motoring press · published 22 June 2023 · consulted 29 October 2026 · in Spanish
  9. ¿Qué pasa si el coche se queda sin aceite?RACE · Motoring press · published 26 August 2020 · consulted 29 October 2026 · in Spanish