BMW Cooling System Parts & Accessories for BMW 3 Series E46 (1999-2005)

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The cooling system is arguably the weakest point in numerous BMWs. If you drive an aging BMW or plan on taking your car to the track like we do, we recommend beefing up your cooling system before going to the track. Generally, the main components in your cooling system that are prone to failure include the following: expansion tank, factory hoses, water pump, thermostat, fan (especially if your vehicle comes factory with a clutch fan), and radiator. Factory BMW expansion tanks are plastic and prone to either breaking off at connection points or combusting. As factory rubber hoses age they either crack or break over time - we offer silicone cooling hose upgrades for most applications to avoid future failures. If you have an older vehicle, your water pump likely comes from the factory with a plastic impeller - we offer upgraded water pumps with metal impellers that are far more reliable. Newer model BMWs utilize electric water pumps - BMW spent millions of dollars engineering these water pumps, but they fail so often that we recommend replacing at 60,000 mile service intervals to avoid being stranded on the side of the road. In terms of thermostats, we offer various upgraded thermostats for racing applications. If your BMW utilizes a clutch fan from the factory, we have several options available in terms of universal electric fans - we recommend replacing these to avoid sending brittle plastic fan blades through your hood. For radiators, we recommend swapping out your radiator for one that does not use plastic connection points like your factory radiator.

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Moroso Performance Aluminum Expansion Tank - E46 M3
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Moroso - Corporate Logo
T#:568945
Part#: 63793
In Stock at Vendor
$ 433.99 USD
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$ 433.99 USD
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If you have ever experienced a leaking plastic BMW expansion tank you will realize the value of this aluminum version straight away. Even if a failure has not happened to you, it's easy to tell this tank is much stronger and more durable than the plastic used in the stock design. The original BMW plastic tanks suffer from leaks and failures with no warning. While being lightweight and recyclable, the design and construction of the stock tank is just not up for reliable long-term use. Moroso coolant expansion tanks are all pressure tested for guaranteed leak-free operation. Features: Direct bolt-in replacement to stock, cracked, or discolored tanks Fabricated Aluminum for strength, factory tanks fail after repeated high heat situations & age No cutting of factory hoses is required and accepts the factory clip-on hose Included is a Moroso Part No. 63324 racing radiator cap that operates in the same pressure range as the factory cap The Moroso radiator cap mounts to a billet aluminum neck that will not strip out like plastic threaded necks Easy to read slight level is included
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OEM Febi Auxiliary Fan Switch
Mounted in upper radiator hose, controls operation of auxiliary fan Mounted in lower radiator hose, controls operation of auxiliary fan
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Febi - Corporate Logo
T#:340712
Part#: 13621433077
Ships on Oct 7, 2026
$ 29.99 USD
Free Shipping on orders $49 and up
$ 29.99 USD
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The auxiliary fan switch activates the auxiliary cooling fan to provide additional cooling under high heat loads, and when the car is stationary.
BMW Coolant / Antifreeze - 1.5L
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Febi - Corporate Logo
T#:16175674
Part#: 82141467704
Ships on Oct 7, 2026
$ 70.99 USD
Free Shipping on orders $49 and up
Coolant G11 (Concentrate). The right anti-freeze agent makes a key contribution towards the reliable functioning of the engine cooling system under all operating and weather conditions. Cooler anti-freeze agents from Febi are precisely matched to the special requirements of the vehicle manufacturer and offer reliable protection from damages caused by freezing, corrosion, and cavitation. A good functioning cooling system is a primary prerequisite for the optimum operation of the engine. The ideal mixing ratio is 1:1, which offers frost protection to -36° C. With a ratio of 1:1 of water and concentrate, the boiling point of the cooling is approximately 107° C.+ High protection against freezing, corrosion, and cavitation Prevention of deposits and foam formation
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Heater Inlet Pipe
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Febi - Corporate Logo
T#:594084
Part#: 11531705210
Ships on Jul 28, 2026
$ 47.46 USD
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Runs from the front left side of the engine to the heater inlet

Febi Radiator Fan Clutch - E34, E36, E39, E46, E53, Z3
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Febi - Corporate Logo
T#:382395
Part#: 11527505302
Ships on Oct 7, 2026
$ 187.99 USD
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$ 187.99 USD
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Common source of engine overheating
Febi Temperature Sensor
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Febi - Corporate Logo
T#:340711
Part#: 13621433076
In Stock at Vendor
$ 17.99

This product was last offered at the strikethrough price on
06-22-2026

$ 16.99 USD
Free Shipping on orders $49 and up
$ 16.99 USD
Free Shipping on orders $49 and up
Monitors coolant / oil temperature

Febi Freeze Plug - 11111714712
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Febi - Corporate Logo
T#:6570
Part#: 11111714712
In Stock at Vendor
$ 3.99

This product was last offered at the strikethrough price on
05-07-2026

$ 1.81 USD
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$ 1.81 USD
Free Shipping on orders $49 and up
ENGINE COVER LID 11111714712
BMW Coolant Flange
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Febi - Corporate Logo
T#:17339423
Part#: 17111707817
Special Order: No Guaranteed ETA
$ 47.99 USD
$ 47.99 USD
Water distribution pipe that connects the expansion tank to the radiator

Coolant Hose With Quick Connectors
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Febi - Corporate Logo
T#:17339415
Part#: 11531436410
Special Order: No Guaranteed ETA
$ 28.99 USD
$ 28.99 USD
Over the years and with exposure to extremely hot coolant, the coolant hoses in your vehicle can take a beating. Being made of reinforced rubber, these hoses can fail in a number of ways. Splitting at a hose clamp, swelling, cracking, and breaking are just a few of the ways this hose can leave you stranded. Replace it at the first sign of wear to keep your coolant in your engine.
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