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BMW Z4 E85/E86 (2002–2008)Faults with the thermostat and cooling system

Thermostat and cooling system of the BMW Z4 E85/E86: problems and faults

In the BMW Z4 E85/E86 there are 3 documented faults with the thermostat and cooling system: thermostat and water pump failure (BMW M54 engine), cracked expansion tank and coolant leak (BMW M54 engine) and electric water pump and thermostat failure (BMW N52 / N53 engine).

Most serious fault: High severity

3 sourcesHow we work

Faults by engine

From most to least important. Check the affected years and versions on each page.

Symptoms these faults cause

How much the repair costs

Depending on the fault, at an independent garage it ranges from €350[3] (electric water pump and thermostat failure) to €600[3] (electric water pump and thermostat failure), including VAT. If the fault is caught in time, the repair is usually much cheaper.

Parts for the BMW Z4 E85/E86 for faults with the thermostat and cooling system

The same search across several shops so you can compare prices. The part number varies with the engine and year: confirm it with the registration plate or VIN.

Affiliate links: if you buy from these shops, MotorFiable may receive a commission at no cost to you. Check compatibility against the registration plate or VIN before ordering. Affiliate links

Frequently asked questions

What faults with the thermostat and cooling system does the BMW Z4 E85/E86 have?

In the BMW Z4 E85/E86 there are 3 documented faults with the thermostat and cooling system: thermostat and water pump failure (BMW M54 engine), cracked expansion tank and coolant leak (BMW M54 engine) and electric water pump and thermostat failure (BMW N52 / N53 engine). Each fault has its own page with the affected years and versions, the symptoms and how to check for it.

Thermostat and cooling system of the BMW Z4 E85/E86: how much does the repair cost?

Depending on the fault, at an independent garage it ranges from €350 (electric water pump and thermostat failure) to €600 (electric water pump and thermostat failure), including VAT.

Which engines of the BMW Z4 E85/E86 have faults with the thermostat and cooling system?

The documented faults affect the BMW M54 and BMW N52 / N53 engines. Check the years and versions on each page: they do not always affect every unit.

Have you had a fault with the thermostat and cooling system on your BMW Z4 E85/E86? Tell us 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. M54 Engine ProblemsBMW Tuning · Technical documentation · consulted 5 October 2026
  2. Fallo del depósito de expansión del BMW Serie 5 E39Euro Premium Parts · Technical documentation · consulted 5 October 2026 · in another language
  3. Problemas BMW N52Total Renting · Other source · consulted 5 October 2026 · in Spanish