BMW Cooling System Parts & Accessories for BMW Z Series E85/6 (2003-2008)

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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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Packaged by Turner - Corporate Logo
T#:5376274
Part#: 11517586925TKT
In Stock
Sale - Save 25% $ 448.99

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

$ 337.56 USD
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Sale - Save 25%
$ 448.99

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

$ 337.56 USD
Free Shipping
Everything you need to replace your water pump and thermostat. The water pumps in these BMW models are known for failure near 80,000 miles is a very common issue often times leaving the owner stranded. The aftermarket kit offered provides a single stop for water pump and thermostat replacement needs to save the search and get you back on the road. Kit includes: Mahle-Behr thermostat Water pump Genuine BMW coolant thermostat to water pump hose Mounting hardware required for both the thermostat and water pump
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Packaged by Turner - Corporate Logo
T#:339100
Part#: TMS224320
In Stock at Vendor
Starting at $ 514.24 USD
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Starting at $ 514.24 USD
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This is a customizable cooling system overhaul kit, which starts off with the basic radiator and water pump and can be configured to replace all the M54 common cooling system failure parts in one package. This cooling system package is for the 2003-2005 Z4 Roadster.

The Z4 cooling system is much like that of the sister 3 series. Several of the primary cooling components are prone to failure within 60k miles (or less in many cases). A failure in the cooling system can lead to overheating and catastrophic engine failure. Don't gamble your engine! By replacing these core items preventatively, such as the radiator & waterpump, you are defusing what could be a ticking cooling system time bomb. And if you've had a failure of one of these parts, now is the time to refresh your cooling system. Available with our kit is an OEM Behr radiator, an Original BMW water pump (with updated composite impeller), thermostat (complete with housing), radiator cap, new hoses, and other essential cooling parts.

Optional items (which can be added below):
  • Radiator cap
  • Major cooling hoses
  • Original BMW antifreeze
  • Upgrade the water pump to a Stewart EMP High Performance pump
  • Add a new coolant expansion tank (known for cracking)
  • Include a new coolant level sensor (known for failing / throwing "check coolant" messages)
  • Include a new coolant temp sensor (located in the lower radiator hose) (re-using the old sensor and seal may lead to a leak)
  • Add a new thermostat for an automatic transmission (located with the expansion tank).
    This cooling system overhaul kit fits the following BMWs:
    2003-2005 E85 BMW Z4 2.5i Z4 3.0i

    Please put a check in the boxes next to the items you wish to order.
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    Packaged by Turner - Corporate Logo
    T#:554073
    Part#: 11537509227KT3
    Ships on Jan 12, 2027
    $ 101.99 USD
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    $ 101.99 USD
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    When it comes time to replace your thermostat, be sure you have everything you need. This kit includes everything you need to replace your thermostat, including the thermostat.

    Kit includes:

    • Mahle-Behr thermostat with gasket
    • Thermostat mounting hardware
    • 1 liter of coolant

    Applications:
    1999-2003 E39 528i, 525i, 530i sedan, touring wagon (M52TU engine, M54 engine)
    1999-2005 E46 323, 328, 325, 330 sedan, coupe, cabrio, touring wagon (M52TU engine, M54 engine)
    2004-2005 E60 525i, 530i sedan, touring wagon (M54 engine)
    2001-2006 E53 X5 3.0 (M54 engine)
    2004-2006 E83 X3 2.5i X3 3.0i (M54 engine)
    1999-2002 Z3 2.3. Z3 2.5i, 2.8 Z3 3.0i (M54 engine)
    2003-2005 Z4 2.5i, Z4 3.0 (M54 engine)

     

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    Packaged by Turner - Corporate Logo
    T#:339099
    Part#: TMS16430
    In Stock at Vendor
    Starting at $ 514.24 USD
    Free Shipping
    Starting at $ 514.24 USD
    Free Shipping
    This is a customizable cooling system overhaul kit, which starts off with the basic radiator and water pump and can be configured to replace all the M54 common cooling system failure parts in one package. This cooling system package is for the 2003-2005 Z4 Roadster.

    The Z4 cooling system is much like that of the sister 3 series. Several of the primary cooling components are prone to failure within 60k miles (or less in many cases). A failure in the cooling system can lead to overheating and catastrophic engine failure. Don't gamble your engine! By replacing these core items preventatively, such as the radiator & waterpump, you are defusing what could be a ticking cooling system time bomb. And if you've had a failure of one of these parts, now is the time to refresh your cooling system. Available with our kit is an OEM Behr radiator, an Original BMW water pump (with updated composite impeller), thermostat (complete with housing), radiator cap, new hoses, and other essential cooling parts.

    Optional items (which can be added below):
  • Radiator cap
  • Major cooling hoses
  • Original BMW antifreeze
  • Upgrade the water pump to a Stewart EMP High Performance pump
  • Add a new coolant expansion tank (known for cracking)
  • Include a new coolant level sensor (known for failing / throwing "check coolant" messages)
  • Include a new coolant temp sensor (located in the lower radiator hose) (re-using the old sensor and seal may lead to a leak)
  • Add a new thermostat for an automatic transmission (located with the expansion tank).
    This cooling system overhaul kit fits the following BMWs:
    4/2004-2005 E85 BMW Z4 2.5i Z4 3.0i

    Please put a check in the boxes next to the items you wish to order.
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    ECS - Corporate Logo
    T#:363707
    Part#: 001977ECS03A
    In Stock
    Sale - Save 5% $ 104.99

    This product was last offered at the strikethrough price on
    06-13-2026

    $ 99.74 USD
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    Sale - Save 5%
    $ 104.99

    This product was last offered at the strikethrough price on
    06-13-2026

    $ 99.74 USD
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    Most of the pulleys on your BMW engine are plastic, which become brittle and frail over time and from engine bay heat. A failed pulley could leave you stranded which is why it is vital to inspect the pulleys during routine maintenance. This is an aluminum version of the stock water pump pulley used on the M50/M52/M52TU/M54 engine in the E36, E46, Z3, Z4, and other models. It uses the same hardware and the original belt as the stock plastic pulley. But the aluminum will last much longer.
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    ECS Silicone Radiator Hoses - N52
    For Vehicles With Engine Code N52B30 (Non-SULEV w/o Auxiliary Heating)
    ECS - Corporate Logo
    T#:37723492
    Part#: 008641LA03
    In Stock
    Sale - Save 10% $ 130.99

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

    $ 117.89 USD
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    Sale - Save 10%
    $ 130.99

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

    $ 117.89 USD
    Free Shipping

    Tired of dealing with brittle, dry-rotted rubber hoses? Whether you're refreshing your cooling system or replacing aging components, this ECS Silicone Radiator Coolant Hose Set is the ultimate upgrade. Designed for durability, performance, and a factory-perfect fit, these premium silicone hoses outperform standard rubber in every way.

    Why Choose Silicone Over Rubber?

    Made from heavy-duty, reinforced 4-ply fluorosilicone, ECS hoses withstand extreme temperatures and pressures far beyond OEM rubber hoses. Engineered to resist oil, fuel, and electrochemical degradation, these hoses are tested for continuous operation at 250°F and over 45 psi, delivering superior reliability, reduced turbulence, and improved coolant flow.

    Key Benefits:

    Direct OE Fitment – Perfectly molded to factory specifications for seamless installation. Enhanced Durability – Heat-resistant silicone prevents cracking, swelling, and deterioration over time. Superior Cooling Performance – Smoother internal passageways improve coolant flow and system efficiency. Pre-Installed Quick-Connect Fittings – Hassle-free installation with OEM-style connectors. Premium Hardware Included – Comes with German-style stainless steel worm-drive hose clamps for a secure fit. Kit Includes:

    Upper Radiator Hose Lower Radiator Hose Pre-Installed Factory "Quick-Connect" Flanges (4) Stainless Steel Worm-Drive Hose Clamps (4) Replaces OEM Part Numbers: 17127531579 & 17127564478

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    ECS - Corporate Logo
    T#:367060
    Part#: 002778ECS01
    Ships on Dec 3, 2026
    Sale - Save 10% $ 100.99

    This product was last offered at the strikethrough price on
    06-13-2026

    $ 90.89 USD
    Free Shipping
    Sale - Save 10%
    $ 100.99

    This product was last offered at the strikethrough price on
    06-13-2026

    $ 90.89 USD
    Free Shipping
    Most of the pulleys on your BMW engine are plastic, which become brittle and frail over time and from engine bay heat. A failed pulley could leave you stranded which is why it is vital to inspect the pulleys during routine maintenance. This is an aluminum version of the stock water pump pulley used on the S54 engine in the E46 M3, MZ3, and Z4M. It's the same size and uses the same hardware and the original belt as the stock plastic pulley. But the aluminum will last much longer.
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    ECS - Corporate Logo
    T#:568837
    Part#: 020414ECS01KT
    In Stock
    Sale - Save 25% $ 113.99

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

    $ 85.49 USD
    Free Shipping
    Sale - Save 25%
    $ 113.99

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

    $ 85.49 USD
    Free Shipping

    ECS - Corporate Logo
    T#:599848
    Part#: 004481LA01
    In Stock
    Sale - Save 15% $ 113.99

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

    $ 96.89 USD
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    Sale - Save 15%
    $ 113.99

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

    $ 96.89 USD
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    The perfect upgrade for your connection between your thermostat and cylinder head. Designed using durable silicone and billet aluminum to greatly outlast the OE rubber and plastic combination. Some of the weakest points of the cooling systems in BMW's can come down to the OE plastic fittings breaking down from the constant changes in temperature, softening these plastic components. When this happens, even simply moving the hose slightly could cause the fitting to crack, causing the coolant to leak all over. The ECS design silicone hose with billet aluminum adapter retains OE fitment with superior strength to not only handle the performance, but also stand up to the wear and tear of a daily driver. Features: Manufactured from billet 6061-T6 and type III anodized for exceptional durability and corrosion resistance. Much stronger part than OEM plastic Will not become brittle and fatigue over time due to thermal cycling. This will prevent the part from breaking during removal and re-installation. Constructed of 4-Ply reinforced silicone for improved durability over the failure-prone OE rubber hose. Flourosilicone lined internal layer for exceptional chemical resistance. Silicone offers reduced thermal conductivity as well as improved resistance to ozone and UV degradation for improved performance and durability. Follows OEM form for perfect fitment. Utilizes OEM O-ring 11537545278 to ensure a proper seal. Replaces Genuine BMW Part Number: 11537545890
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    ECS Silicone Radiator Hoses - N52
    For SULEV Vehicles with Engine Code N51B30 & Auxiliary Heating (S536A)
    ECS - Corporate Logo
    T#:32516370
    Part#: 008641LA02
    In Stock
    Sale - Save 20% $ 130.99

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

    $ 104.79 USD
    Free Shipping
    Sale - Save 20%
    $ 130.99

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

    $ 104.79 USD
    Free Shipping

    Tired of dealing with brittle, dry-rotted rubber hoses? Whether you're refreshing your cooling system or replacing aging components, this ECS Silicone Radiator Coolant Hose Set is the ultimate upgrade. Designed for durability, performance, and a factory-perfect fit, these premium silicone hoses outperform standard rubber in every way.

    Why Choose Silicone Over Rubber?

    Made from heavy-duty, reinforced 4-ply fluorosilicone, ECS hoses withstand extreme temperatures and pressures far beyond OEM rubber hoses. Engineered to resist oil, fuel, and electrochemical degradation, these hoses are tested for continuous operation at 250°F and over 45 psi, delivering superior reliability, reduced turbulence, and improved coolant flow.

    Key Benefits:

    Direct OE Fitment – Perfectly molded to factory specifications for seamless installation. Enhanced Durability – Heat-resistant silicone prevents cracking, swelling, and deterioration over time. Superior Cooling Performance – Smoother internal passageways improve coolant flow and system efficiency. Pre-Installed Quick-Connect Fittings – Hassle-free installation with OEM-style connectors. Premium Hardware Included – Comes with German-style stainless steel worm-drive hose clamps for a secure fit. Kit Includes:

    Upper Radiator Hose Lower Radiator Hose Pre-Installed Factory "Quick-Connect" Flanges (4) Stainless Steel Worm-Drive Hose Clamps (4) Replaces OEM Part Numbers: 17127531579 & 17127564478

    Show More Show Less
    ECS - Corporate Logo
    T#:49822518
    Part#: 044952LA04KT
    In Stock
    New Item
    Sale - Save 25% $ 477.99

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

    $ 358.49 USD
    Free Shipping
    Sale - Save 25%
    $ 477.99

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

    $ 358.49 USD
    Free Shipping

    The N5X family of engines marked the start of a new era for BMW. The all-new aluminum block powerplants featured a host of technical upgrades, aiding in power output, reliability, and performance. Among these technological advances is an external electronic water pump, which removed load from the engine's accessory drive and allowed for advanced pulse-width-modulated (PWM) control.

    From factory, the N52's electronic water pump is limited to a measly 200W output—strong enough for daily driving, but lacking in performance applications. Recognizing this shortcoming, ECS engineers set out to create a high-flow water pump upgrade that doesn't break the bank. Their high-quality adapter wiring harness and bracket allow you to install a 400W N54 water pump without any modification, an effortless, yet effective upgrade that doubles the output of the factory water pump!

    By increasing coolant flow capacity, the 400W pump improves heat extraction from the cylinder head and engine block during high-load operation. This added thermal headroom is particularly beneficial for modified engines, sustained aggressive driving, track use, or operation in elevated ambient temperatures where the factory pump can operate near its limits. Improved circulation helps maintain more stable coolant temperatures and reduces the risk of localized hot spots.

    Features & Benefits:

    Upgrades to the more powerful 400W N54 water pump for increased coolant flow and improved engine cooling efficiency Sealed adaptor harness ensures secure connections and optimal operation under demanding conditions The N54 pump's higher power output offers longer-lasting, more effective cooling compared to the stock N52 pump Design:

    40A fused power wire safely handles the increased power demands of the N54 pump, providing consistent and stable performance Sealed and robust construction, designed to withstand heat and moisture, ensuring reliability in even the most challenging environments Plug-and-play compatibility is designed for easy integration with the N52 engine and N54 water pump, minimizing installation time and complexity Kit Contents:

    ECS N54 Water Pump Adapter Kit Conversion wiring harness Aluminum bracket Installation hardware Bavarian Autosport Water Pump (11517632426)

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    ECS - Corporate Logo
    T#:49822519
    Part#: 044952LA04AKT
    In Stock
    New Item
    $ 597.99 USD
    Free Shipping
    $ 597.99 USD
    Free Shipping

    The N5X family of engines marked the start of a new era for BMW. The all-new aluminum block powerplants featured a host of technical upgrades, aiding in power output, reliability, and performance. Among these technological advances is an external electronic water pump, which removed load from the engine's accessory drive and allowed for advanced pulse-width-modulated (PWM) control.

    From factory, the N52's electronic water pump is limited to a measly 200W output—strong enough for daily driving, but lacking in performance applications. Recognizing this shortcoming, ECS engineers set out to create a high-flow water pump upgrade that doesn't break the bank. Their high-quality adapter wiring harness and bracket allow you to install a 400W N54 water pump without any modification, an effortless, yet effective upgrade that doubles the output of the factory water pump!

    By increasing coolant flow capacity, the 400W pump improves heat extraction from the cylinder head and engine block during high-load operation. This added thermal headroom is particularly beneficial for modified engines, sustained aggressive driving, track use, or operation in elevated ambient temperatures where the factory pump can operate near its limits. Improved circulation helps maintain more stable coolant temperatures and reduces the risk of localized hot spots.

    Features & Benefits:

    Upgrades to the more powerful 400W N54 water pump for increased coolant flow and improved engine cooling efficiency Sealed adaptor harness ensures secure connections and optimal operation under demanding conditions The N54 pump's higher power output offers longer-lasting, more effective cooling compared to the stock N52 pump Design:

    40A fused power wire safely handles the increased power demands of the N54 pump, providing consistent and stable performance Sealed and robust construction, designed to withstand heat and moisture, ensuring reliability in even the most challenging environments Plug-and-play compatibility is designed for easy integration with the N52 engine and N54 water pump, minimizing installation time and complexity Kit Contents:

    ECS N54 Water Pump Adapter Kit Conversion wiring harness Aluminum bracket Installation hardware Pierburg Full Aluminum Water Pump (11515A05704) Installation:

    - Click HERE for Installation Instructions -

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