Skip to content
MotorFiable
en

BMW Z4 E85/E86 (2002–2008)NoisesUrgency: As soon as possible

Deep metallic engine knock in the BMW Z4 E85/E86: causes

In the BMW Z4 E85/E86, 2 documented faults may be the cause: wear and breakage of the timing chain guides (BMW N43/N46 engine) and N52 hydraulic lifter noise (BMW N52 / N53 engine).[1][3][4]

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.

General explanation. Engine knock: faults that cause it in all cars

8 sourcesHow we work

Engine and gearbox faults that cause it in the Z4 E85/E86

Only those that affect the versions and years this car was fitted with. Below each title, how the symptom shows up in that fault.

Other common causes: engine knock

In addition to the documented faults of the BMW Z4 E85/E86, these are the most common causes in any car according to the sources.

  • Play in the big-end or main bearings (rod knock)[5][6]Common
  • Lack of lubrication: low or degraded oil or insufficient pressure[6][7]Common
  • Stretched timing chain or tensioner without pressure[5][6][8]Possible
  • Hydraulic tappets and valves with play[5][6]Possible
  • Worn pistons and rings[6]Uncommon
  • Normal diesel engine noise[6]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.[5][7]
  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.[5][7]
  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).[5][6]
  4. Look for oil leaks on the ground or blue smoke, signs that the engine is losing or burning oil, according to RACE.[7]
Complete guide: deep metallic engine knock

Frequently asked questions

Engine knock in the BMW Z4 E85/E86: what could it be?

In the BMW Z4 E85/E86, 2 documented faults may be the cause: wear and breakage of the timing chain guides (BMW N43/N46 engine) and N52 hydraulic lifter noise (BMW N52 / N53 engine). 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 Z4 E85/E86: 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 in this car has critical severity.

Has your BMW Z4 E85/E86 had this happen? Tell us which fault it was, at what mileage and how much you paid. Report your fault.

Sources

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

  1. BMW N43Wikipedia (inglés) · Other source · consulted 27 September 2026
  2. BMW N43: Bei diesem Benziner ist Ärger vorprogrammiertGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
  3. BMW N52 Engine ProblemsBMW Tuning · Other source · consulted 5 October 2026
  4. These BMW N52 Years Have The Most ProblemsJalopnik · General press · consulted 5 October 2026
  5. El motor hace ruido en frío: qué es cada ruido y cuál preocupaTodoaditivos · Other source · consulted 29 October 2026 · in Spanish
  6. ¿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
  7. ¿Qué pasa si el coche se queda sin aceite?RACE · Motoring press · published 26 August 2020 · consulted 29 October 2026 · in Spanish
  8. Las graves (y costosas) averías que puede causar en tu coche la rotura de la cadena de distribuciónDiariomotor · Motoring press · published 17 July 2020 · consulted 29 October 2026 · in Spanish