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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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

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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$ 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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:638094

Part#: 17111723520

In Stock

Sale - Save 20% $ 39.99

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

$ 31.99 USD

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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:638080

Part#: 11531705210

In Stock

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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:638085

Part#: 11537502525

In Stock

Sale - Save 20% $ 50.99

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

$ 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 - E39 540i M5 - Manual Transmi...

For vehicles with manual transmission and production date from 09/1998

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
2X Entries For Our G87 M2 Sweepstakes!

T#:401086

Part#: 7064

In Stock

$ 689.00 USD

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$ 689.00 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:
09/1998+ E39 BMW 540i, M5 with a manual transmission

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CSF OE Style Radiator - E39 525/528/530/540

For vehicles with production date from 09/1998 - Fits Auto or Manual Models For vehicles with production date from 09/1998 and a manual transmission Fits Auto or Manual Models

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
2X Entries For Our G87 M2 Sweepstakes!

T#:638785

Part#: 2919

Ships in 2 Business Days

$ 94.99 USD

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$ 94.99 USD

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CSF radiators are designed and built to High-Performance Standards & sold worldwide for over 50 years - over 30 Million Units Sold! CSF's radiators are carefully engineered and Wind Tunnel tested for Cooling Performance Validation. CSF has over 10,000 different models of radiators that they manufacture and supply for all the leading brands of vehicles on the road.

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CSF OE Style Radiator - E39 528i (up to 09/1998)

For vehicles with production date up to 09/1998

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
2X Entries For Our G87 M2 Sweepstakes!

T#:638786

Part#: 2918

In Stock

$ 113.99 USD

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$ 113.99 USD

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CSF radiators are designed and built to High-Performance Standards & sold worldwide for over 50 years - over 30 Million Units Sold! CSF's radiators are carefully engineered and Wind Tunnel tested for Cooling Performance Validation. CSF has over 10,000 different models of radiators that they manufacture and supply for all the leading brands of vehicles on the road.

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

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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:639828

Part#: 13621703993

Ships on Oct 7, 2026

Sale - Save 20% $ 20.99

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

$ 16.79 USD

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$ 20.99

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

For vehicles with production date up to 09/1998

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:639793

Part#: 61318360855

In Stock

Sale - Save 19% $ 20.99

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

$ 16.99 USD

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Sale - Save 19%

$ 20.99

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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

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
06-03-2026

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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
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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