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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Turner Motorsport - Corporate Logo
T#:338927
Part#: HOSE-CLAMPS
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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.
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Bavarian Autosport - Corporate Logo
T#:12544802
Part#: 11531437040
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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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Bavarian Autosport - Corporate Logo
T#:599823
Part#: 11517586925
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$ 269.99 USD
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Don't take your car's cooling system for granted. A waterpump failure can cost you an engine, which is why preventatively replacing your BMWs waterpump and refreshing the cooling system every 60,000 miles. The water pump is a weak point is the cooling system. Replacing your waterpump will go a long way for keeping your car on the road and operating properly. This water pump fits many 2006 and newer BMW 6 cylinder engines, specifically all the BMWs with the N51, N52, N53 engines. You will also need to purchase replacement aluminum screws Part #11510392553 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. This water pump fits the following BMWs: 2008-20xx E82 128i 2006-2006 E90 325i sedan, 330i sedan, 325xi sedan, 330xi sedan 2007-2012 E90 328i sedan, 328xi sedan, 328i xDrive sedan 2007-2012 E92 328i coupe, 328xi coupe, 328i xDrive coupe 2007-2012 E93 328i Convertible 2006-2006 E60 525i, 525xi, 530i, 530xi 2007-2010 E60 528i, 528xi, 528i xDrive 2007-2010 E83 X3 3.0i X3 3.0si 2007-20xx E70 X5 3.0si X5 xDrive30i 2006-2008 E85 Z4 3.0si 2009-20xx E89 Z4 sDrive30i
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Bavarian Autosport - Corporate Logo
T#:638085
Part#: 11537502525
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$ 40.79 USD
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This product was last offered at the strikethrough price on
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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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Vargas Turbo Technologies - Corporate Logo
T#:7530036
Part#: COOLANTCAPBLUE
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$ 79.99 USD
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$ 79.99 USD
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VTT is proud to offer their billet replacement for the factory plastic Coolant Reservoir cap. This cap does away with the weak plastic cap while adding some pop, and color to your engine bay. This coolant cap retains ALL of the factory provisions by simply allowing you to snap the factory pressure-relief into the new Billet Cap. VTT also designed these caps to complement their N5X Billet Oil caps, N5XBillet Oil filter housing caps, and Billet Power Steering cap, so all 4 will have the same design. These caps are offered in 4 colors – Red, Black, Blue, and Clear anodized Replaces Genuine BMW Reservoir Cap # 17117639020 Note: Fitment includes 99% of all BMW with a coolant Reservoir tank from the E series forward, meaning then fit even the brand New G8X M3/4 with the S58, all B58, etc. If your BMW is an E90 or newer this cap most likely will fit
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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans ...
For vehicles with an automatic transmission only
Bavarian Autosport - Corporate Logo
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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This product was last offered at the strikethrough price on
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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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Redline - Corporate Logo
T#:640437
Part#: 81205
In Stock
$ 68.99 USD
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$ 68.99 USD
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Red Line SuperCool Concentrate fortified with WaterWetter is a concentrated antifreeze/coolant designed to maximize the performance of your cooling system with superior protection against cavitation corrosion/erosion. Using SuperCool Concentrate diluted with distilled water protects the entire cooling system keeping new components like new for 5 years/150,000 miles and prevents further damage to older components. Red Line’s proprietary coolant additive formula enhances the fluid’s ability to transfer heat, reducing operating temperatures by up to 20*F and prolonging the life of the entire cooling system. Red Line's SuperCool is an OAT coolant that is a Nitrate and Silicate Free product with its own proprietary corrosion technology to offer superior protection for aluminum engines found in all European vehicles, performance vehicles, as well as other applications. SuperCool will not void the factory warranty either. It can be used to top off the existing coolant of any BMW and will not cause any ill-effects on the cooling system because it is silicate and nitrate free. It is still better to flush it out and switch completely to SuperCool to get all the full benefits of the product in performance and protection.
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Vargas Turbo Technologies - Corporate Logo
T#:7530034
Part#: COOLANTCAPRED
Ships in 1 Business Day
$ 79.99 USD
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$ 79.99 USD
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VTT is proud to offer their billet replacement for the factory plastic Coolant Reservoir cap. This cap does away with the weak plastic cap while adding some pop, and color to your engine bay. This coolant cap retains ALL of the factory provisions by simply allowing you to snap the factory pressure-relief into the new Billet Cap. VTT also designed these caps to complement their N5X Billet Oil caps, N5XBillet Oil filter housing caps, and Billet Power Steering cap, so all 4 will have the same design. These caps are offered in 4 colors – Red, Black, Blue, and Clear anodized Replaces Genuine BMW Reservoir Cap # 17117639020 Note: Fitment includes 99% of all BMW with a coolant Reservoir tank from the E series forward, meaning then fit even the brand New G8X M3/4 with the S58, all B58, etc. If your BMW is an E90 or newer this cap most likely will fit
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Redline - Corporate Logo
T#:640436
Part#: 81215
Ships on Aug 17, 2026
$ 54.99 USD
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Red Line SuperCool Performance Coolant fortified with WaterWetter is a 50/50 prediluted antifreeze/coolant designed to maximize the performance of your cooling system with superior protection against cavitation corrosion/erosion. Using 100% SuperCool Performance protects the entire cooling system, keeping new components like new for 5 years/150,000 miles and prevents further damage to older components. Red Line’s proprietary coolant additive formula enhances the fluid’s ability to transfer heat, reducing operating temperatures by up to 20*F and prolonging the life of the entire cooling system. Red Line's SuperCool is an OAT coolant that is a Nitrate and Silicate Free product with its own proprietary corrosion technology to offer superior protection for aluminum engines found in all European vehicles, performance vehicles, as well as other applications. SuperCool will not void the factory warranty either. It can be used to top off the existing coolant of any BMW and will not cause any ill-effects on the cooling system because it is silicate and nitrate free. It is still better to flush it out and switch completely to SuperCool to get all the full benefits of the product in performance and protection.
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VTT Billet Coolant Reservoir Cap - Anodized Clear - Most BMWs 2006+ (...
This coolant cap retains ALL of the factory provisions by simply allowing you to snap t...
Vargas Turbo Technologies - Corporate Logo
T#:7530035
Part#: COOLANTCAPRAW
Ships in 3 Business Days
$ 78.99 USD
Free Shipping
$ 78.99 USD
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VTT is proud to offer their billet replacement for the factory plastic Coolant Reservoir cap. This cap does away with the weak plastic cap while adding some pop, and color to your engine bay. This coolant cap retains ALL of the factory provisions by simply allowing you to snap the factory pressure-relief into the new Billet Cap. VTT also designed these caps to complement their N5X Billet Oil caps, N5XBillet Oil filter housing caps, and Billet Power Steering cap, so all 4 will have the same design. These caps are offered in 4 colors – Red, Black, Blue, and Clear anodized Replaces Genuine BMW Reservoir Cap # 17117639020 Note: Fitment includes 99% of all BMW with a coolant Reservoir tank from the E series forward, meaning then fit even the brand New G8X M3/4 with the S58, all B58, etc. If your BMW is an E90 or newer this cap most likely will fit
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Genuine BMW Motorsport - Corporate Logo
T#:1171
Part#: TMS1171
Ships in 7 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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Vargas Turbo Technologies - Corporate Logo
T#:7530033
Part#: COOLANTCAPBLK
Back Ordered
$ 79.99 USD
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$ 79.99 USD
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VTT is proud to offer their billet replacement for the factory plastic Coolant Reservoir cap. This cap does away with the weak plastic cap while adding some pop, and color to your engine bay. This coolant cap retains ALL of the factory provisions by simply allowing you to snap the factory pressure-relief into the new Billet Cap. VTT also designed these caps to complement their N5X Billet Oil caps, N5XBillet Oil filter housing caps, and Billet Power Steering cap, so all 4 will have the same design. These caps are offered in 4 colors – Red, Black, Blue, and Clear anodized Replaces Genuine BMW Reservoir Cap # 17117639020 Note: Fitment includes 99% of all BMW with a coolant Reservoir tank from the E series forward, meaning then fit even the brand New G8X M3/4 with the S58, all B58, etc. If your BMW is an E90 or newer this cap most likely will fit
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Genuine BMW Motorsport - Corporate Logo
T#:337991
Part#: 11531417215
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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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Bavarian Autosport - Corporate Logo
T#:640208
Part#: 17117639022
In Stock
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This product was last offered at the strikethrough price on
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$ 11.89 USD
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Sale - Save 15%
$ 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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Redline - Corporate Logo
T#:394769
Part#: REDLINE5A
In Stock
Starting at $ 15.99 USD
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Starting at $ 15.99 USD
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Water Wetter is a unique wetting agent for cooling systems which reduces coolant temperatures by as much as 30*F. This liquid product can be used to provide rust and corrosion protection in plain water for racing engines, which provides much better heat transfer properties than glycol-based antifreeze.
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Redline - Corporate Logo
T#:3607
Part#: 1-WW-12Z
In Stock
$ 15.99 USD
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Water Wetter is a unique wetting agent for cooling systems which reduces coolant temperatures by as much as 30*F. This liquid product can be used to provide rust and corrosion protection in plain water for racing engines, which provides much better heat transfer properties than glycol-based antifreeze. Or it can be added to new or used antifreeze to improve the heat transfer of ethylene and propylene glycol systems. Designed for modern aluminum, cast iron, copper, brass, and bronze systems.

We have been using RedLine Oil in our street cars and race cars for years. Hands-down, it is the Number One brand of high performance lubricant for BMWs.
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Bavarian Autosport - Corporate Logo
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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