Aluminium Thermostat and Housing in OE Supplier

A cooling part: aluminium rather than the plastic housing that warps at the mating face and weeps.

We are an independent parts supplier. We are not BMW AG or MINI, we are not appointed by them, and BMW and MINI are their trademarks. What we sell are parts that fit those cars, described as such. Every listing states the chassis codes and engine codes it fits, the production date range, which quality tier you are buying, the labour time the job actually takes, and whether the part needs coding to the car before it will work. Where a part is only made in plastic by the factory and fails because it is plastic, we say so and we offer the metal one.

Specification and fitment

• Fits: 1 Series E87 F20, 3 Series E46 E90 E91 E92 E93 F30 F31, 4 Series F32 F33, 5 Series E39 E60 F10, X3 E83 F25, X5 E53 E70 F15, Mini R56 F56 R60 F60
• Engine: chosen above. These cars change mid production, sometimes twice in a model year, and two cars built four months apart can take different parts. Send us the last seven digits of your VIN with the order and we check the part against the build record before anything is dispatched. It takes us two minutes and it is the difference between a part that fits and a return.
• Production dates: 1998 to 2019 depending on chassis
• Quality: made by the firm that supplies the vehicle manufacturer, in that firm's own box rather than a dealer box. Identical part, identical line, no dealer margin, and this is what we would fit ourselves
• Part number: cross referenced to the original equipment number for your VIN and confirmed before dispatch. We do not publish a single number against a listing that covers several build variants, because that is how people order the wrong part
• The failure this addresses: Almost every cooling failure on these cars is a plastic part doing a job that heat makes plastic bad at: a water pump with a plastic impeller, an expansion tank that splits at the seam, a thermostat housing that warps. The electric water pump on the N52 and N54 typically goes between 60,000 and 90,000 miles and takes the head gasket with it if you keep driving. If yours is original and the car has done 70,000, it is not a question of whether.
• Labour time: one to four hours depending on the part, and the coolant flange behind the inlet manifold is at the top of that range
• Coding: no coding, but the adaptation values want resetting with a diagnostic tool afterwards or the car will run on the old learned figures for a while
• Also needed: coolant to the correct specification, new O rings and hose clips, and a vacuum fill afterwards
• Torque: plastic housings are torqued low and in sequence. Overtightening one cracks it on the bench and the crack does not show until it is warm
• Weight: approximately 1.2 kilograms
• Warranty: three years or 36,000 miles, whichever comes first
• Vacuum fill: these systems are filled under vacuum. An air lock will cook a head gasket while the gauge reads normal, because the sender is measuring coolant and the trouble is the air
• Uprated: the metal impeller and aluminium versions are on this page and are what we would fit
• Do the set: a cooling system is a set of plastic parts of the same age. One new part among eleven old ones buys months
• Coolant: the blue and the later green must not be mixed. Mixed coolant gels and blocks the heater matrix, which is a dashboard out repair

What arrives

• the part as described
• O rings, gaskets and clips
• coolant where the item includes it
• instructions with torque figures and the vacuum fill note

Fitting

One to four hours. Fill under vacuum rather than pouring it in, because an air lock in one of these systems will destroy a head gasket while the temperature gauge sits happily in the middle.

Which version to buy

The only real decision is plastic or metal. The factory used plastic because it is light and cheap and it lasted the warranty. The metal impeller pump and the aluminium thermostat housing cost a little more and remove the failure permanently. On a car you intend to keep past ten years, that is the easiest money in this shop. Almost every cooling failure on these cars is a plastic part doing a job that heat makes plastic bad at: a water pump with a plastic impeller, an expansion tank that splits at the seam, a thermostat housing that warps. The electric water pump on the N52 and N54 typically goes between 60,000 and 90,000 miles and takes the head gasket with it if you keep driving. If yours is original and the car has done 70,000, it is not a question of whether.