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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Bremmen Parts - Corporate Logo
T#:640204
Part#: 17127510952
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Replacement Upper Radiator Hose for E46 3 series (Non-M3). We recommend replacing the Coolant Temperature Sensor while replacing this hose as the original sensor is often damaged while trying to remove it from the old hose. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.
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Bremmen Parts - Corporate Logo
T#:26494584
Part#: 11537509227
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Bremmen Parts - Corporate Logo
T#:27572101
Part#: 64218376153
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$ 38.34 USD
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Bremmen Parts - Corporate Logo
T#:36913373
Part#: 17117561757
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$ 165.59 USD
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The auxiliary fan in your vehicle serves an extremely important role. When your car reaches temperatures that may be hazardous to your engine, the auxiliary fan moves air through the radiator to provide better cooling. Usually activated during times of stationary vehicle operation, it supplements the air usually driven through the radiator by driving down the road.

If your vehicle is getting too hot during traffic or at stop lights, your auxiliary fans are probably faulty. Replace yours with this piece from Bremmen Parts to restore the factory cooling in your vehicle and prevent catastrophic damage to your engine. Even if your fans are still operational but the blades are damaged or cracked, replacement is the only solution.

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Bremmen Parts - Corporate Logo
T#:38655188
Part#: 11537830715
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$ 22.53 USD
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Bremmen Parts - Corporate Logo
T#:38621426
Part#: 11537830716
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$ 20.39 USD
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Meyle Coolant Expansion Tank - E53 X5, E46 M52/54, E83 X3
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Meyle - Corporate Logo
T#:369184
Part#: 17117573781
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$ 66.99 USD
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We have found that the expansion tanks should be replaced based on age as well as condition. Expansion tanks seem to have a lifespan of less than six years before they show signs of fatigue and wear. Pre-emptively replacing the expansion tank as part of an overall maintenance plan can prevent you from getting stranded from a sudden failure later on.

Other items to consider replacing at the same time are the radiator cap, coolant level sensor, lower radiator hose, coolant temp sensor, and the hose clamps. If your car has an automatic transmission you should also replace the oil cooler thermostat in the radiator frame, which is a common source for leaks.

As a leading source of high-performance BMW parts and accessories since 1993, we at Turner Motorsport are honored to be the go-to supplier for tens of thousands of enthusiasts the world over. With over two decades of parts, service, and racing experience under our belt, we provide only quality performance and replacement parts. All of our performance parts are those we would (and do!) install and run on our own cars, as well as replacement parts that are Genuine BMW or from OEM manufacturers. We only offer parts we know you can trust to perform!

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Bremmen Parts - Corporate Logo
T#:36981064
Part#: 11531436406
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$ 31.99

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$ 24.99 USD
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Over time, prolonged exposure to high-temperature coolant can take a toll on your vehicle's hoses. Made from reinforced rubber, these hoses are prone to wear and failure in various ways, including splitting at hose clamps, swelling, cracking, or breaking. Any of these issues can lead to coolant loss and potentially leave you stranded. Replacing your hoses at the first sign of wear is essential to maintaining a properly functioning cooling system.

This replacement hose is designed with the correct diameter, bends, and length for a precise fit, making it an ideal solution for swelled or damaged hoses. With straightforward installation, this hose provides peace of mind, whether you're embarking on a long road trip or simply commuting to work.

When replacing your radiator hose, some coolant loss is unavoidable. Browse our website to find the exact replacement coolant and other parts for your vehicle, delivered straight to your door. Don’t forget to order a new thermostat housing as well—factory plastic units often crack or warp during removal, and replacing them ensures a complete and reliable repair.

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Bremmen Parts - Corporate Logo
T#:36981061
Part#: 11537502000
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Water pipes play a crucial role in maintaining proper engine cooling. If cracked, they must be replaced immediately to prevent engine overheating. This water pipe runs from the rear of the water pump housing to the expansion tank hose. It comes complete with all necessary seals for a hassle-free installation.
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Bremmen Parts - Corporate Logo
T#:15511829
Part#: 17 111437362
Ships on Aug 13, 2026
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$ 36.85 USD
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Heat exchanger for your automatic transmission, usually changed when you replace your expansion tank.
Water Pump and Seal - with upgraded metal impeller - MEYLE
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Meyle - Corporate Logo
T#:579324
Part#: 11517509985
Ships on Nov 30, 2026
$ 52.99 USD
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Ensure the optimal performance of your BMW by addressing the crucial component of the water pump. Turner Motorsport provides high-quality water pumps designed to keep coolant flowing smoothly. If left unchecked, a failing water pump can lead to overheating issues, potentially causing damage to engine internals. Common among German vehicles, water pump failure may result in unnecessary visits to the repair shop. Preventive maintenance, especially during timing belt replacements, is essential to avoid rapid coolant temperature rise and potential engine damage.

  • Prevents overheating issues
  • Guards against engine damage
  • Common replacement during timing belt maintenance
  • Ensures smooth coolant flow for optimal engine performance
  • Options for thermostats available on Turner Motorsport's website
  • Convenient coolant replacement options
  • Recommended replacement around 60,000 miles
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Bremmen Parts - Corporate Logo
T#:36981065
Part#: 11517838159
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A failing water pump is a recipe for engine overheating and costly internal damage. Keep your coolant flowing and your engine protected by replacing your aging pump with this high-quality OE unit from Bremmen Parts.

Water pump replacement is suggested at 60,000 - 80,000 miles.

This pump includes the alignment dowel, sealing gasket, and thermostat sealing o-ring. We recommend picking up a water pipe sealing o-ring (11537830712) and thermostat (11531318274) for a comprehensive service.

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Sachs Radiator Fan Clutch - E34, E36, E39, E46, E53, Z3
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Sachs - Corporate Logo
T#:591739
Part#: 11527505302
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$ 133.99

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Common source of engine overheating
Bremmen Parts - Corporate Logo
T#:640140
Part#: 17111712788
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$ 2.44 USD
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$ 2.44 USD
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Plastic bleeder screw for cooling system is used to bleed air that would otherwise create an air pocket and lead to overheating. Includes o-ring seal.
Bremmen Auxiliary Fan Temperature Switch - E46 E39 E9X E60 E70 E53 ...
Mounted in upper radiator hose, controls operation of auxiliary fan Mounted in lower radiator hose, controls operation of auxiliary fan
Bremmen Parts - Corporate Logo
T#:640141
Part#: 13621433077
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$ 16.79 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

Bremmen Parts - Corporate Logo
T#:38621424
Part#: 64218363198
Ships on Aug 19, 2026
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$ 8.66 USD
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Meyle Expansion Tank Cap
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Meyle - Corporate Logo
T#:579357
Part#: 3148009004
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Replace worn or missing pieces.
Behr - Corporate Logo
T#:338021
Part#: 17119071518
In Stock at Vendor
Starting at $ 249.99 USD
Starting at $ 249.99 USD
This is a BEHR brand (OEM supplier to BMW) replacement radiator for all 1999-2006 E46 3 series (non-M), including 323i, 323Ci, 328i, 328Ci, 325i, 325Ci, 330i, 330Ci, and Z4 2.5 and 3.0. Compare to BMW list price of $318! Save big, while still getting the highest quality radiator available for your BMW.

This radiator fits the follow BMWs: :
Only for Manual Transmission
1999-5/2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi - Not for cars with M56 engine

2003-2006 E85 BMW Z4 2.5i Z4 3.0i - M54 engine
2006-2008 E85 BMW Z4 M Roadster M Coupe
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Elring - Corporate Logo
T#:45278657
Part#: 293.300
Special Order: No Guaranteed ETA
$ 3.99 USD
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Seals the thermostat and thermostat housing to the water pump Replaces BMW # 11531318402
Bremmen Parts - Corporate Logo
T#:640149
Part#: 11521712058
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$ 18.76 USD
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This fan is driven by the serpentine belt, engaged by the fan clutch. If you have bad motor mounts, it's quite common for the blades of this fan to make contact with the radiator or radiator shroud, essentially self-destructing the fan into many pieces. Be sure to get a new fan clutch, while you are replacing this.
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Bremmen Parts - Corporate Logo
T#:38621423
Part#: 64218376999
Ships in 1-3 days
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Auxillary 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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Meyle - Corporate Logo
T#:4934936
Part#: 3148210000
Special Order: No Guaranteed ETA
$ 18.99 USD
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$ 18.99 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. Also known as the coolant temperature sending unit, comes with related o-ring
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Fluid Level Sensor
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Meyle - Corporate Logo
T#:5973204
Part#: 17117546548
Special Order: No Guaranteed ETA
$ 13.99 USD
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MEYLE-ORIGINAL: True to OE fluid level sensor. Used in multiple locations. Wulf Gaertner Autoparts AG manufactures and markets automotive spare parts under its MEYLE brand. Since its foundation in 1958, Wulf Gaertner Autoparts has been an owner-operated, unlisted family business on the aftermarket scene. Since 1995, Wulf Gaertner Autoparts AG has been manufacturing and trading under its MEYLE brand. They pride themselves on top-grade quality-tested spare parts for passenger cars, vans and commercial vehicles. Comparable OE Cross Reference - 17117546548
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Meyle - Corporate Logo
T#:40478120
Part#: 11531436408
Special Order: No Guaranteed ETA
$ 32.99 USD
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Upgrade your BMW’s cooling system with a dependable solution that meets or exceeds OEM quality.


Coolant Flange - Rear/Engine Block
Fits European models only
Meyle - Corporate Logo
T#:55533481
Part#: 11531708808
Special Order: No Guaranteed ETA
New Item
$ 9.99 USD
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$ 9.99 USD
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This Meyle Original-grade replacement coolant flange is the perfect solution for refreshing your BMW’s cooling plumbing back to factory-fresh operation.
Meistersatz - Corporate Logo
T#:379740
Part#: 13621433076
Ships in 4 Business Days
$ 15.99 USD
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Monitors coolant / oil temperature