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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

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T#:12544802

Part#: 11531437040

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$ 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

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T#:640496

Part#: 17137787039

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$ 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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CSF High Performance Aluminum Radiator - E46

For vehicles with manual transmission only

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T#:384650

Part#: 3055

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$ 409.00 USD

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$ 409.00 USD

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CSF is one of the premier cooling product specialists available on the market thanks to designs such as their High Performance Aluminum Radiators. Using a single pass designed core, this radiator gives you all the cooling you could ever need. Paired with these radiators are CNC machined brackets and corrosion resistant hardware that allow final installation to have a same as stock fitment! This enables you to have much higher cooling without having to cut away any metal or delete any important components just for the sake of lower coolant temperatures.

Features:

Two-row, triple-pass design radiator core
CNC machined mounting brackets
All needed hardware included
Hand polished aluminum with a mirror-like finish
Stock fitment prevents modification to engine bay

Fits the following BMWs:
1998-2006 E46 BMW All Submodels
2002-2008 E85/86 BMW M Coupe & M Roadster

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CSF OE Style Radiator - E46 Non-M (Manual Transmission)

For vehicles with Manual transmission only

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T#:582782

Part#: 3708

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$ 110.99 USD

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$ 110.99 USD

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This is a factory original style radiator from CSF and will fit perfectly into the stock location. Cooling will be identical to what your car came with originally. A great replacement with all the proper connections and in all of the proper locations.

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

For vehicles with a manual transmission only

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T#:638088

Part#: 17111436250

In Stock

Sale - Save 20% $ 44.99

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$ 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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CSF OE Style Radiator - E85/86 Z4 M, E46 Non-M (Automatic Transmissio...

For vehicles with automatic transmission only

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T#:582698

Part#: 3709

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$ 110.99 USD

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$ 110.99 USD

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This is a factory original style radiator from CSF and will fit perfectly into the stock location. Cooling will be identical to what your car came with originally. A great replacement with all the proper connections and in all of the proper locations.

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

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T#:638080

Part#: 11531705210

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Sale - Save 20% $ 40.99

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05-03-2026

$ 32.79 USD

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$ 40.99

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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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Bavarian Autosport Water Pipe - E46 E39 Z4 Z3 (M52TU, M54)

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T#:638085

Part#: 11537502525

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Sale - Save 20% $ 50.99

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$ 40.79 USD

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Qty

Sale - Save 20%

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This product was last offered at the strikethrough price on
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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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CSF High Performance Aluminum Radiator - E46 M3

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T#:384654

Part#: 7058

In Stock

$ 645.00 USD

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$ 645.00 USD

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CSF is one of the premier cooling product specialists available on the market thanks to designs such as their High Performance Aluminum Radiators. Using a two-row, triple-pass designed core, this radiator gives you all the cooling you could ever need. Paired with these radiators are CNC machined brackets and corrosion resistant hardware that allow final installation to have a same as stock fitment! This enables you to have much higher cooling without having to cut away any metal or delete any important components just for the sake of lower coolant temperatures.

Features:

Two-row, triple-pass design radiator core
CNC machined mounting brackets
All needed hardware included
Hand polished aluminum with a mirror-like finish
Stock fitment prevents modification to engine bay

Fits the following BMWs:
2001-2006 E46 BMW M3

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

For vehicles with an automatic transmission only

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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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Qty

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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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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BMW S54 Swap High-Performance Radiator - E36/E46

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T#:15180812

Part#: 7211

EO#: D-802-19

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$ 599.00 USD

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$ 599.00 USD

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The S54 is arguably one of the greatest BMW motors of all time. Power delivery, balance, and sound are top notch. While it doesn’t compare in power potential to newer turbo powered inline 6 motors, many enthusiasts still love and crave the NA power delivery that BMW was and still is famous for. Despite not being the most powerful option, the S54 Swap has become increasingly popular in the BMW community for the E36 Chassis.

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BMW S54 Swap Race-Spec Oil Cooler - E36/E46

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T#:15180814

Part#: 8240

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$ 519.00 USD

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$ 519.00 USD

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The ONLY choice for your S54 swapped E36 or E46. The new CSF S54 Swap Race Spec Oil Cooler is shorter on the right hand side allowing owners to run the A/C lines in the OEM path. Even though the #8240 is slightly smaller than the #8032, you can expect similar performance levels as they both feature a dual pass design with 8 cooling rows and are the same turbulated heavy-duty bar/plate construction.

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Water Connection Pipe

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T#:15511839

Part#: 17111707817

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Sale - Save 20% $ 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 ...

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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

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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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BMW E46 M3 Oil Line -10 AN Adapter Fitting Kit

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T#:31158758

Part#: 8241

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$ 89.00 USD

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$ 89.00 USD

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BMW Oil Line -10 AN Adapter Fitting Kit is designed for optimal performance with both oil cooler and thermostat housing setups. This comprehensive kit from Turner Motorsport provides everything needed for a secure and reliable connection.

Each fitting kit includes:

Qty. 2 - Aluminum -10 AN to ORB Fittings
Qty. 2 - O-Rings
Qty. 1 - Aluminum Fitting Bracket
Qty. 1 - M8 Mounting Bolt

Note: If using a -10 AN connection on the thermostat housing side, a second fitting kit is required.

Benefits:

Enhances connection reliability for oil cooler and thermostat housing
High-quality aluminum fittings ensure durability and performance
Includes all necessary components for easy installation
Compatible with CSF #8240 (BMW S54 Swap Race Spec Oil Cooler) and CSF #8032 (BMW E46 M3/S54 Race-Spec Oil Cooler)

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CSF Universal Large Single-Pass Oil Cooler - Universal Application ...

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Universal fitment design - modifications may be necessary to run this cooler

T#:53608839

Part#: 8371

Ships in 3 Business Days

$ 499.00 USD

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$ 499.00 USD

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CSF redesigned this cooler and went with a more traditional inlet/outlet orientation. The new single pass design features high efficiency and high durability, but with vertically oriented inlet and outlet connections.

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

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T#:639833

Part#: 13621433076

In Stock

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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