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BMW Cooling System Parts & Accessories for BMW 5 Series E39 (1996-2003)

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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

For vehicles with production date from 09/1998

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 - E36 E39 Z3 M50 M52 S50 S52 ...

For vehicles with production date up to 08/1998

T#:638094

Part#: 17111723520

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$ 31.99 USD

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Replace your old expansion tank to prevent potential failure or leaks. Includes a brand new coolant level sensor. 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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Thermostat With Housing - 90C

For vehicles with a production date from 09/1998

T#:598978

Part#: 11531436386

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$ 75.06 USD

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A thermostat that opens sooner promotes better cooling in your vehicle. Running a lower temperature thermostat will keep everything much cooler. Keeping the engine cooler will help reduce and improve the life of the seals in your engine, saving you time and money, while also help increase engine performance. A tune might be required to gain the most from this modification, as well as to get your car's ECU accustomed to seeing lower temperatures.

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

T#:638080

Part#: 11531705210

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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)

T#:638085

Part#: 11537502525

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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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Thermostat With Housing

T#:26494584

Part#: 11537509227

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$ 49.99 USD

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Coolant Expansion Tank

T#:36032353

Part#: 17111741167

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$ 47.32 USD

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Upper Radiator Hose - E38 E39 M62

For vehicles with production date from 09/1998

T#:36100134

Part#: 11537505228

In Stock

$ 52.99

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$ 38.99 USD

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$ 52.99

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This OEM-style upper radiator hose connects the upper radiator outlet to the thermostat housing.

If you're experiencing a leak or wear in your radiator hose, replace it with this high-quality, cost-effective replacement from Bremmen Parts to restore optimal cooling system performance.

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Coolant Expansion Tank - 17111436381

For vehicles with production date from 09/1998

T#:36303285

Part#: 17111436381

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$ 52.79 USD

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BMW E39 Coolant Expansion Tank is an essential component designed to maintain the proper coolant level in your vehicle's cooling system. Manufactured with high-quality materials, this expansion tank ensures reliable performance and durability, preventing engine overheating by accommodating the expansion of coolant as it heats up. The kit includes a level sensor and cap, providing everything needed for a seamless installation. This expansion tank is specifically engineered to meet the exact specifications of your BMW E39, offering a perfect fit and optimal functionality.

Complete Kit: Includes level sensor and cap for easy installation. High-Quality Construction: Built with durable materials for long-lasting performance. Prevents Overheating: Helps manage coolant expansion, ensuring engine protection. Exact Fit: Designed to meet the precise specifications of your BMW E39. Enhanced Reliability: Ensures proper coolant level maintenance for optimal cooling system function.

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Bremmen Coolant Bleeder Screw - BMW E30 E36 E38 E39 E46 E83 E90 Z4 ...

T#:640140

Part#: 17111712788

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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.

Bav Auto Coolant Temperature Sensor - M52/S52, M62, M73, M54, S62 ...

Located on water pump housing For vehicles with production date from 09/1998

T#:639828

Part#: 13621703993

Ships on Oct 14, 2026

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$ 16.79 USD

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This is the coolant temperature sensor used in many BMW models from the mid-1990s to the mid-2000s. 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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E39 Upper Radiator Hose - 11531705223

For vehicles with production date from 09/1998

T#:36100154

Part#: 11531705223

In Stock

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$ 37.53 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 Auxiliary Fan Temperature Switch - E46 E39 E9X E60 E70 E53 ...

For vehicles with production date from 09/1998

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

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

T#:640208

Part#: 17117639022

In Stock

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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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Radiator Hose - Lower

T#:39768309

Part#: 11531741409

In Stock

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$ 15.50 USD

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E39 Lower Radiator Hose - 11531705224

For vehicles with production date from 09/1998

T#:36100127

Part#: 11531705224

In Stock

Sale - Save 21% $ 36.99

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$ 29.37 USD

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Over time, and with prolonged exposure to high-temperature coolant, the hoses in your vehicle's cooling system endure significant wear and tear. Made from reinforced rubber, these hoses can fail in various ways, including splitting near hose clamps, swelling, cracking, or even rupturing completely. Any of these failures can lead to coolant loss and leave you stranded. Replace your coolant hoses at the first sign of wear to ensure your engine stays properly cooled and running reliably.

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Bav Auto Coolant Level Sensor - BMW E36 E39 M50/52 S50/52

For vehicles with production date up to 09/1998

T#:639793

Part#: 61318360855

In Stock

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This product was last offered at the strikethrough price on
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$ 16.99 USD

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This is the sensor / sending unit that notifies the computer if your coolant level is low. When this fails, it can give a false indication of low coolant -- or worse, not inform you of a low coolant situation that could potentially cause overheating. 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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Hose Clamp - 40mm-60mm

T#:5227

Part#: 040-60T

Ships in 4 Business Days

$ 3.99 USD

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Hose clamps for radiator hoses, coolant hoses, vacuum hoses, or intake hoses. These hose clamps are the same style as your OEM hoses with a smooth inside band to prevent cutting into the hose material.

Features:

9mm band width

6mm hex & slotted head

Smooth inside of band = optimal hose protection

OEM

430 Stainless steel band and housing with zinc plated steel screw

Asymmetric housing = even distribution of forces and prevents tilting of the clamp when tightening

Screw support = ease of assembly due to the safe guidance of the emerging band

Short housing saddle = even contact pressure = improved efficiency

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Thermostat With Housing - 105C

T#:15511816

Part#: 11531436386

Ships in 8 Business Days

Sale - Save 4% $ 30.99

This product was last offered at the strikethrough price on
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$ 29.67 USD

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A thermostat that opens sooner promotes better cooling in your vehicle. Running a lower temperature thermostat will keep everything much cooler. Keeping the engine cooler will help reduce and improve the life of the seals in your engine, saving you time and money, while also help increase engine performance. A tune might be required to gain the most from this modification, as well as to get your car's ECU accustomed to seeing lower temperatures.

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

T#:640149

Part#: 11521712058

In Stock

Sale - Save 22% $ 23.99

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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 Thermostat Assembly - E38, E39

For vehicles with production date up to 09/1998

T#:388457

Part#: 11531437526

Back Ordered

Sale - Save 15% $ 56.99

This product was last offered at the strikethrough price on
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$ 48.44 USD

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Comes with aluminum housing, o-ring & sensor

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