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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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Bav Auto Thermostat With Aluminum Housing - M52TU M54

T#:12544802

Part#: 11531437040

In Stock

Sale - Save 19% $ 104.99

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05-03-2026

$ 84.99 USD

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The plastic thermostat cover in your BMW is a known point of failure. Throughout years of repeated contact with hot coolant, the plastic can crack and cause massive coolant leaks and potential overheating. Eliminate one of the weak links in your cooling system with a replacement aluminum thermostat housing. By installing this aluminum unit, you have no worries as far as plastic housing cracks go

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Bav Auto Coolant Expansion Tank - E53 X5, E46, E83 X3

T#:640496

Part#: 17137787039

In Stock

Sale - Save 18% $ 61.99

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05-03-2026

$ 50.99 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. 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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Bav Auto Heater Inlet Pipe - E46 E39 E53 E83 E85 Z3

T#:638080

Part#: 11531705210

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Sale - Save 20% $ 40.99

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

$ 32.79 USD

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This is the plastic heater inlet pipe that connects the cylinder head to the heater inlet on cars with the M52 or M54 engine. The plastic on this hose becomes brittle over time and eventually leads to failure. Replace yours with a brand new Bav Auto Heater inlet pipe to prevent catastrophic failure.

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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Manual Trans ...

For vehicles with a manual transmission only

T#:638088

Part#: 17111436250

In Stock

Sale - Save 20% $ 44.99

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

$ 35.99 USD

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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on an E46 3 series with a Manual Transmission. 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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Bavarian Autosport Water Pipe - E46 E39 Z4 Z3 (M52TU, M54)

T#:638085

Part#: 11537502525

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Sale - Save 20% $ 50.99

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$ 40.79 USD

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This plastic water pipe is positioned directly underneath your intake manifold. Due to its plastic construction, it is notorious for catastrophic failure. Rapid cooling loss and overheating are both direct results of this failure, posing permanent and lasting damage to the engine.

Replace your cracked/broken coolant pipe with this high-quality Bavarian Autosport component to ensure long-term reliability and perfect fitment.

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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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans ...

For vehicles with an automatic transmission only

T#:638089

Part#: 17111436251

In Stock

Sale - Save 20% $ 45.99

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

$ 36.79 USD

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Sale - Save 20%

$ 45.99

This product was last offered at the strikethrough price on
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$ 36.79 USD

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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on E46 3 series and E85/E86 Z4 with an Automatic Transmission. 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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Active Autowerke Sport Fan Clutch - E36 E46

T#:397219

Part#: 14-010

Ships in 2 Business Days

5% off MSRP $ 259.00

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 246.99 USD

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5% off MSRP

$ 259.00

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 246.99 USD

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When you push your powerplant, thermodynamics push right back. The toll of high performance is higher heat load – and many stock components begin to complain. But Active Autowerke has you covered - this upgraded fan clutch increases viscous coupling of cooling fan blade speed to water pump speed, yielding increased airflow through the radiator for more efficient cooling. A simple, yet wonderful, thing.

This product fits the following BMWs:
1992-1999 E36 323i 325i 328i 330i M3
1998-2006 E46 323i 325i 328i 330i M3

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Motorsport Thermostat - 60C - Complete with Housing - M54 / M52tu ...

T#:1171

Part#: TMS1171

Ships in 9 Business Days

$ 415.45 USD

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$ 415.45 USD

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This is a genuine BMW Motorsport part, designed specifically for BMW racing applications. We use this exact thermostat setup in our Championship-winning E46 330i race car. It is designed to be used on all M54 and M52TU double-VAN0S engines, as used in the 1999-2000 E46 323/328 and 2001-2005 E46 325/330. This 60 degree C (140 defrees F) thermostat comes complete with plastic thermostat housing. It does not use the plug and wiring for the stock DME so this should only be used with an aftermarket engine management system (Motec, Bosch, etc).

When doing any sort of repair or maintenance there is no replacement for genuine factory parts. Turner Motorsport carries the Genuine BMW brand with pride and has the parts you need to complete your next project with confidence.

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Sachs Radiator Fan Clutch - E34, E36, E39, E46, E53, Z3

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:591739

Part#: 11527505302

Back Ordered

$ 231.08 USD

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$ 231.08 USD

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Common source of engine overheating

Motorsport Thermostat - 55 (NO LONGER AVAILABLE)

T#:337991

Part#: 11531417215

Back Ordered

Starting at $ 232.98 USD

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Starting at $ 232.98 USD

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E46M3 Motorsport Thermostat 55C (Also fits Euro E36 M3 engine) A Genuine BMW part this thermostat opens at a much lower temperature than stock to keep your S54 engine (or Euro S50/S52 engine) running cooler in race applications.

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Water Connection Pipe

T#:15511839

Part#: 17111707817

In Stock

Sale - Save 20% $ 18.99

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

$ 15.19 USD

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$ 18.99

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$ 15.19 USD

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Connects the radiator to the expansion tank

Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 ...

T#:640208

Part#: 17117639022

In Stock

Sale - Save 15% $ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 USD

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$ 13.99

This product was last offered at the strikethrough price on
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$ 11.89 USD

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This radiator expansion tank cap is used most BMW's from 1991-2006. It is a common failure item. When this item fails, it cannot hold pressure which results in your BMW overheating. If you are overhauling your coolant system, now is the time to consider preventative replacing this cap. It is also referred to as the coolant reservoir cap. 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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Bav Auto Temperature Sensor - BMW E39 E46 E9X E60 F01/02

T#:639833

Part#: 13621433076

In Stock

Sale - Save 20% $ 14.99

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

$ 11.99 USD

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Sale - Save 20%

$ 14.99

This product was last offered at the strikethrough price on
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$ 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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