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BMW Cooling System Parts & Accessories for BMW E46 M3 S54 (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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O-RING

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T#:580584

Part#: C32348

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$ 3.99

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05-07-2026

$ 2.99 USD

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Bracket - Fan Housing - E46

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T#:45829

Part#: 17112282209

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$ 13.99 USD

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Genuine BMW Bracket, Fan Housing
This item fits the following BMW Chassis:
E46 M3,E46

Fits BMW Engines including:
S54

Anti-Freeze Tester

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T#:641679

Part#: CTAA195

Ships on Jul 28, 2026

$ 9.98 USD

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Tests all ethylene glycol solutions with radiator hot or cold

DO88 Aluminum Radiator - Blue Hose - E46 M3

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T#:13891811

Part#: WC310B

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$ 735.99 USD

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The team at DO88 has vigorously tested this radiator to deliver peak performance with the peace of mind of quality for your E46 M3. They guarantee reliability and endurance in all situations to let your car breathe better than before! Boasting a 17% increase in core volume, this upgrade is a no-brainer for petrol heads like us. Keeping core temperatures low eliminates the risk of heat soak leading to overheating giving you max performance at any given moment. no compromise has been made at DO88 leaving you with one of the best radiator options on the market!

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BMW Radiator Expansion Tank Pressure Fitting

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Requires the use of a Motive Power Bleeder, sold separately

T#:380462

Part#: 1175

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$ 24.99 USD

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Allows you to check for leaks in the coolant system

Elring Thermostat O-Ring - BMW S54 3.2L

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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 Engine Fan Blade - 11 Blades, 420mm - BMW M30 S38 M50 M52 S5...

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T#:640149

Part#: 11521712058

In Stock

Sale - Save 22% $ 23.99

This product was last offered at the strikethrough price on
05-03-2026

$ 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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2 Pin Connector

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T#:33412932

Part#: 61132359999

Ships on Jul 28, 2026

Sale - Save 25% $ 10.99

This product was last offered at the strikethrough price on
06-14-2026

$ 8.24 USD

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Includes connector housing with terminals and seals. Commonly used for the coolant level sensor.

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

*OEM cross reference PN# 61132359999 - Commonly used for the coolant level sensor.

Please reference the original part number from the existing connector to confirm fitment, before ordering.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

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Bav Auto Temperature Sensor - BMW E39 E46 E9X E60 F01/02

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T#:639833

Part#: 13621433076

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This product was last offered at the strikethrough price on
05-03-2026

$ 11.99 USD

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This is the coolant temperature sensor used in many BMW models from the late-1990s to the mid-2010s. The engine computer relies on the coolant temp to set the fuel mapping for the engine. As the car warms up the computer changes the fuel mixture. If your car is running a bit rich (too much fuel) it could be because this sensor is failing and not sending the correct info to the computer. This sensor is located in a variety of places depending on the engine. But it's one of those easy replacement items 'while you're in there' when doing a water pump or thermostat replacement. 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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Auxillary Fan Switch

Mounted in upper radiator hose, controls operation of auxiliary fan

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T#:4934936

Part#: 3148210000

Special Order: No Guaranteed ETA

$ 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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T#:5973204

Part#: 17117546548

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$ 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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Coolant Flange - Rear/Engine Block

Fits European models only

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T#:55533481

Part#: 11531708808

Special Order: No Guaranteed ETA

$ 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.

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