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BMW Coolant Expansion Tanks

On certain models, namely E36, E46, and E90, the factory BMW expansion tank is prone to either breaking at connection points or blowing apart altogether. If you're starting to feel like your expansion tank is on borrowed time, it's probably time to replace with either a direct OE replacement, or strengthen your cooling setup with an aluminum expansion tank - we offer numerous performance upgrades for your expansion tank. Especially if you're someone who likes to track your BMW, we recommend upgrading your expansion tank to avoid ruining your track day.
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Packaged by Turner - Corporate Logo
T#:338020
Part#: 17117573781
In Stock at Vendor
Sale - Save 2% $ 140.99

This product was last offered at the strikethrough price on
04-01-2026

Starting at $ 137.98 USD
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Sale - Save 2%
$ 140.99

This product was last offered at the strikethrough price on
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Starting at $ 137.98 USD
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This coolant reservoir is for the non-M E46 3-series models from 1999-2006 (M3 takes a different expansion tank). 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. This is the most recent expansion tank design from Hella-Behr, the OEM supplier to BMW. It replaces the original BMW part number 17137787039.

Other items to consider replacing at the same time are the radiator cap, coolant level sensor, lower radiator hose, coolant temp sensor in the lower hose, and the hose clamps. If your car has an automatic transmission you should also replace the oil cooler thermostat in the radiator frame, which is a common source for leaks.

This coolant expansion tank fits:

1999-2006 E46 3 series - 323i, 323Ci, 325i, 325Ci, 325xi, 328i, 328Ci, 330i, 330Ci & 330xi (**no M)
2004-2008 X3 SAV - X3 2.5, X3 3.0, X3 3.0si
2000-2005 X5 SAV - X5 3.0
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Packaged by Turner - Corporate Logo
T#:27605427
Part#: 17138677649TKT
In Stock at Vendor
Sale - Save 5% $ 208.99

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

$ 198.66 USD
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Sale - Save 5%
$ 208.99

This product was last offered at the strikethrough price on
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$ 198.66 USD
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Genuine BMW expansion tanks have a bad habit of failing after a few years. This has primarily been caused by the plastic construction of the expansion tanks. After enough heat cycles, the plastic becomes brittle and can crack, causing coolant to leak out and air to enter the coolant system. If a failing expansion tank is not addressed soon enough, the coolant loss can lead to an overheating engine. This kit includes two brand new high quality expansion tanks and caps
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Packaged by Turner - Corporate Logo
T#:338018
Part#: 17111723520
In Stock at Vendor
$ 97.99

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

Starting at $ 77.22 USD
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Starting at $ 77.22 USD
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This high quality BEHR brand expansion tank is used on M50, M52, S50 and S52 engines, and is a common failure item on all E36 3 series with 6 cylinder engines (325/328/323 and M3) 1992-1999, Z3 with 2.8 liter, MZ3 Roadster/Coupe (S52), and E39 528i from 1997-1998. BEHR was the original equipment supplier to BMW, so you know the BEHR made expansion tank will be the highest quality available. Be leary of competitors selling this part for less -- is it a BEHR? Probably not. We only carry the BEHR brand expansion tank as it is the only one we use in our own BMWs.

If you are overhauling your coolant system, now is the time to consider preventative replacing this expansion tank. These are known to go bad, causing a leak which can leave you stranded. 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.

Need a new coolant level sensor too? If your coolant level sender is bad, your on board computer will constantly display a "low coolant" message (unless your coolant is actually low...). If you're replacing your expansion tank, now is a great time to replace this failure prone sensor. If you want a new coolant level sensor, simply choose from the option below. Because there are different sensors for different year/model BMWs, please be as specific as possible when you give us your car info during checkout (model, year, production date). Thanks!


This item fits the following BMWs:
1992-1998 E36 BMW 323ic 325i 325is 325ic 328i 328is 328ic M3
1997-1998 E39 BMW 528i
1997-1998 Z3 BMW Z3 2.8
1998-2000 Z3 BMW M Roadster M Coupe (S52)
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Packaged by Turner - Corporate Logo
T#:584232
Part#: 17112283345KT
In Stock
$ 249.99 USD
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$ 249.99 USD
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The expansion tank in your BMW is a vital component of the cooling system, and because of the constant abuse from heat and temperature changes, it often fails. This kit contains all of the basic items needed for a tank replacement.
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Packaged by Turner - Corporate Logo
T#:42099868
Part#: 11537558523TKT
Back Ordered
Sale - Save 19% $ 829.99

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

$ 671.10 USD
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Sale - Save 19%
$ 829.99

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

$ 671.10 USD
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Keep your BMW running at the proper temperature and avoid costly engine repairs with the Cooling System Refresh Kit, the complete maintenance solution trusted by enthusiasts and professionals alike.
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Bavarian Autosport - Corporate Logo
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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Sale - Save 20%
$ 39.99

This product was last offered at the strikethrough price on
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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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Bavarian Autosport - Corporate Logo
T#:640496
Part#: 17137787039
In Stock
Sale - Save 18% $ 61.99

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

$ 50.99 USD
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Sale - Save 18%
$ 61.99

This product was last offered at the strikethrough price on
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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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Precision Raceworks - Corporate Logo
T#:38229115
Part#: 622-0079
In Stock
$ 69.99 USD
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The E9X / E8X Coolant Tank & Power Steering Bracket w/ Harness is all of the hardware necessary to relocate your power steering pump and install a factory coolant tank on the driver's side of your vehicle. These are the same high-quality components that are included with our E9X/ E8X relocated inlet kits.
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Bavarian Autosport - Corporate Logo
T#:638088
Part#: 17111436250
In Stock
Sale - Save 20% $ 44.99

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

$ 35.99 USD
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Sale - Save 20%
$ 44.99

This product was last offered at the strikethrough price on
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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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Vargas Turbo Technologies - Corporate Logo
T#:12184492
Part#: VTT-COOLANT-90-1
In Stock
$ 37.99 USD
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$ 37.99 USD
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Enhance the flexibility of your BMW's coolant system with the Vargas Turbo Technologies 90-Degree Coolant Tank Fitting. Ideal for applications such as single turbo setups or forward-facing intake manifolds, this fitting provides extra clearance and versatile hose routing options.

Key Benefits:

  • Allows hose to run straight down, increasing clearance
  • Made of durable 6061-T6 aluminum for long-lasting performance
  • Anodized black finish for enhanced durability and corrosion resistance
  • Includes fitting and clamp for easy installation

Upgrade your BMW's coolant system with the Vargas Turbo Technologies 90-Degree Coolant Tank Fitting for improved performance and versatility.

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Vargas Turbo Technologies - Corporate Logo
T#:7530036
Part#: COOLANTCAPBLUE
In Stock
$ 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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Bavarian Autosport - Corporate Logo
T#:17704781
Part#: 17137642160
In Stock
Sale - Save 20% $ 98.99

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

$ 79.19 USD
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Sale - Save 20%
$ 98.99

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

$ 79.19 USD
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BMW N47 N55 Expansion Tank from Turner Motorsport is a high-quality replacement designed to address issues with cracked or damaged coolant expansion tanks. Engineered for durability and performance, this expansion tank ensures reliable cooling system function.

  • Durable Construction: Built to withstand high temperatures and pressure, ensuring long-term reliability.
  • Direct Replacement: Engineered as a precise fit for BMW N47 and N55 engines, making installation straightforward and hassle-free.
  • Enhanced Cooling Efficiency: Maintains optimal coolant levels and pressure for effective engine cooling.
  • High-Quality Materials: Manufactured from premium materials to resist cracking and leaks.
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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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Sale - Save 20%
$ 45.99

This product was last offered at the strikethrough price on
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$ 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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Bavarian Autosport - Corporate Logo
T#:640493
Part#: 17138570079
In Stock
Sale - Save 20% $ 78.99

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

$ 63.19 USD
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Sale - Save 20%
$ 78.99

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

$ 63.19 USD
Free Shipping on orders $49 and up
Replace your damaged expansion tank to prevent coolant loss or potential overheating issues. 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#:7530034
Part#: COOLANTCAPRED
In Stock
$ 79.99 USD
Free Shipping
$ 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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Bavarian Autosport - Corporate Logo
T#:638093
Part#: 17138621092
In Stock
Sale - Save 20% $ 60.99

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

$ 48.79 USD
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Sale - Save 20%
$ 60.99

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

$ 48.79 USD
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Replace your old expansion tank to prevent potential failure or leaks. Includes a brand new coolant level sensor.

Vargas Turbo Technologies - Corporate Logo
T#:7530035
Part#: COOLANTCAPRAW
Ships in 4 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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Canton Racing - Corporate Logo
T#:19428667
Part#: 80-272
In Stock
$ 185.00 USD
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Upgrade your Gen1 Mini Cooper & Cooper S with this high-quality coolant expansion/fill tank from Canton Racing. With a billet radiator-style neck designed to accept the Canton Racing part #81-030 pressure cap or any 30 psi radiator-style cap, this aluminum tank offers superior performance and style.
  • Features a billet radiator-style neck for enhanced durability
  • Resolves expansion tank issues with a solid, built-in mount
  • Eliminates worries about separating and leaking plastic tanks
  • Perfectly complements Canton Racing 77-272 MINI power steering tank
Ensure reliability and improve the aesthetic appeal of your engine bay with this Canton Racing Aluminum coolant expansion/fill tank for your Gen1 Mini Cooper & Cooper S.
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Precision Raceworks - Corporate Logo
T#:38161689
Part#: 201-0393-BLU
In Stock
$ 109.99 USD
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BMW Blue Engine Coolant Reservoir Cap is the perfect upgrade for BMW owners looking to enhance both the performance and appearance of their engine bay. Constructed from high-quality billet aluminum, this cap replaces the flimsy plastic factory cap, offering improved durability and a sleek, high-performance aesthetic.

Designed with precision, this coolant reservoir cap incorporates the OEM pressure relief function to maintain proper cooling system operation. Unlike inferior stick-on covers that may loosen over time, this cap is a complete replacement, ensuring a secure, leak-free fit. The blue anodized finish provides superior corrosion resistance, making it a reliable upgrade for daily drivers and track enthusiasts alike.

  • OEM pressure relief function – Ensures proper cooling system performance and safety
  • Billet aluminum construction – Provides enhanced durability and strength over factory plastic caps
  • Direct-fit replacement – Fully replaces the stock cap for a precise, secure fit
  • Blue anodized finish – Resists corrosion, heat, and wear for long-lasting performance
  • Motorsport-inspired design – Adds a sleek, professional look to the engine bay
  • Built for longevity – Engineered to withstand extreme temperatures and coolant exposure

Upgrade your BMW’s cooling system with the BMW Blue Engine Coolant Reservoir Cap, designed for superior reliability and style.

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Precision Raceworks - Corporate Logo
T#:38128032
Part#: 201-0394-SIL
Ships in 7 Business Days
$ 94.99 USD
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BMW Silver Auxiliary Coolant Reservoir Cap is the perfect upgrade for BMW owners looking to enhance both the aesthetics and functionality of their engine bay. Unlike generic aftermarket caps that overlook critical pressure regulation, this precision-engineered cap retains the OEM pressure release functionality, ensuring safe and reliable coolant system performance.

Crafted from high-quality billet aluminum, this reservoir cap offers superior durability and resistance to heat and fluids, preventing warping or degradation over time. Unlike adhesive-based cap covers that can loosen or fall off, this cap is a direct replacement for the factory component, providing a secure, high-performance solution.

  • OEM pressure release functionality – Maintains proper system regulation for optimal coolant performance
  • Premium billet aluminum construction – Offers enhanced durability and longevity
  • Direct replacement design – Secure fit without adhesives or modifications
  • Resistant to heat and fluids – Ensures long-lasting reliability in extreme conditions
  • Performance-inspired look – Adds a sleek, high-end appearance to your engine bay
  • Upgraded durability – Prevents cracking, leaks, and premature wear

Upgrade your BMW’s cooling system with the BMW Silver Auxiliary Coolant Reservoir Cap, blending performance, reliability, and premium styling.

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Canton Racing - Corporate Logo
T#:19428666
Part#: 81-030
In Stock
$ 38.00 USD
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Ensure optimal performance of your Mini's cooling system with the Expansion Tank Pressure Cap - 30 Lbs W10 W11 1.6L Engine. Designed for use with Canton Racing aluminum expansion tanks or similar applications, this 30psi radiator style cap provides reliable pressure control. Keep your engine running smoothly with this essential component.
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Precision Raceworks - Corporate Logo
T#:38161688
Part#: 201-0393-BLK
Ships in 9 Business Days
$ 109.99 USD
Free Shipping on orders $49 and up

BMW Black Engine Coolant Reservoir Cap is a premium upgrade designed to enhance both the functionality and aesthetics of your BMW’s engine bay. Unlike flimsy plastic OEM caps, this high-performance cap is CNC-machined from durable billet aluminum, providing long-lasting strength and a sleek, motorsport-inspired look.

Built with precision, this cap retains the essential OEM pressure release function, ensuring proper cooling system operation without compromise. Unlike inferior adhesive covers that may detach over time, this cap fully replaces the factory component, delivering a secure and reliable fit. With a corrosion-resistant black anodized finish, it withstands extreme temperatures and harsh conditions while elevating your BMW’s under-hood appearance.

  • OEM pressure regulation – Maintains factory-designed pressure release for optimal cooling performance
  • CNC-machined billet aluminum – Provides exceptional durability and long-term reliability
  • Direct replacement – Fully replaces the stock cap, ensuring a perfect fit without modifications
  • Corrosion-resistant anodized finish – Prevents wear and adds a stealthy, high-performance look
  • Heat and fluid-resistant design – Built to withstand extreme temperatures and coolant exposure
  • Enhanced engine bay styling – Offers a sleek, motorsport-inspired upgrade

Upgrade your BMW’s cooling system with the BMW Black Engine Coolant Reservoir Cap, designed for superior performance and long-lasting durability.

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Precision Raceworks - Corporate Logo
T#:38094357
Part#: 601-0055
Ships in 6 Business Days
$ 39.99 USD
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This driver-side coolant tank mounting bracket set is ideal for those with relocated inlets or single turbo kits. It enables you to reposition your factory coolant tank to the driver's side of the engine bay. Best of all, it’s fully compatible with all known charge pipes.
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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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Bavarian Autosport - Corporate Logo
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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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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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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Precision Raceworks - Corporate Logo
T#:1332002
Part#: 201-0050
In Stock
$ 19.99 USD
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The E9X/ E8X coolant tank level sensor extension harness is the same great product that comes standard with Precision Raceworks' E9X/ E8X relocated inlet kits. The coolant tank level sensor extension harness is perfect for those running a relocated coolant reservoir tank or 335D coolant reservoir. This harness plugs right into the factory connector allowing you to extend the position of the sensor without the need to splice any wires.
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Bavarian Autosport - Corporate Logo
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
05-03-2026

$ 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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Vargas Turbo Technologies - Corporate Logo
T#:52164880
Part#: N54CLVTBLKO
Ships in 10 Business Days
New Item
$ 54.99 USD
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$ 54.99 USD
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The VTT N54 Upper Vent Hose is a critical upgrade for any BMW enthusiast looking to eliminate the weakest links in their cooling system.

Vargas Turbo Technologies - Corporate Logo
T#:51848504
Part#: VTT-B58-CEBLUE
Ships in 10 Business Days
New Item
$ 59.99 USD
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$ 59.99 USD
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Elevate your BMW's engine bay while safeguarding your cooling system with the VTT B58 Expansion Tank Hose in Blue.
Precision Raceworks - Corporate Logo
T#:38161691
Part#: 201-0393-SIL
Ships in 8 Business Days
$ 109.99 USD
Free Shipping on orders $49 and up

BMW Silver Engine Coolant Reservoir Cap is a premium upgrade for BMW owners looking to enhance both the performance and appearance of their engine bay. Crafted from high-strength billet aluminum, this cap replaces the factory plastic version, offering superior durability and a refined, professional look.

Designed with functionality in mind, it integrates the OEM pressure relief system to ensure your engine's cooling system remains safe and efficient. Unlike adhesive covers, which can peel or wear over time, this cap is a direct-fit replacement, providing a secure and leak-proof seal. The silver anodized finish not only enhances the visual appeal but also ensures resistance to corrosion, high temperatures, and wear, making it perfect for daily driving and track use.

  • OEM pressure relief integration – Maintains proper cooling system performance and reliability
  • Durable billet aluminum – Outperforms factory plastic caps in longevity and strength
  • Precision-machined for perfect fitment – Replaces the stock cap securely, not just a cover
  • Anodized silver finish – Offers corrosion, heat, and wear resistance
  • Elevates engine bay aesthetics – Adds a clean, professional appearance
  • Built for both street and track use – Designed to withstand extreme conditions

Enhance your BMW’s cooling system with the BMW Silver Engine Coolant Reservoir Cap, providing both style and functionality for years to come.

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Precision Raceworks - Corporate Logo
T#:38128029
Part#: 201-0394-BLU
Ships in 9 Business Days
$ 94.99 USD
Free Shipping on orders $49 and up

BMW Blue Auxiliary Coolant Reservoir Cap is the perfect upgrade for BMW owners looking to enhance both the aesthetics and functionality of their engine bay. Unlike generic aftermarket caps that overlook critical pressure regulation, this precision-engineered cap retains the OEM pressure release functionality, ensuring safe and reliable coolant system performance.

Crafted from high-quality billet aluminum, this reservoir cap offers superior durability and resistance to heat and fluids, preventing warping or degradation over time. Unlike adhesive-based cap covers that can loosen or fall off, this cap is a direct replacement for the factory component, providing a secure, high-performance solution.

  • OEM pressure release functionality – Maintains proper system regulation for optimal coolant performance
  • Premium billet aluminum construction – Offers enhanced durability and longevity
  • Direct replacement design – Secure fit without adhesives or modifications
  • Resistant to heat and fluids – Ensures long-lasting reliability in extreme conditions
  • Performance-inspired look – Adds a sleek, high-end appearance to your engine bay
  • Upgraded durability – Prevents cracking, leaks, and premature wear

Upgrade your BMW’s cooling system with the BMW Blue Auxiliary Coolant Reservoir Cap, blending performance, reliability, and premium styling.

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Precision Raceworks - Corporate Logo
T#:38128031
Part#: 201-0394-BLK
Ships in 9 Business Days
$ 94.99 USD
Free Shipping on orders $49 and up

BMW Black Auxiliary Coolant Reservoir Cap is the perfect upgrade for BMW owners looking to enhance both the aesthetics and functionality of their engine bay. Unlike generic aftermarket caps that overlook critical pressure regulation, this precision-engineered cap retains the OEM pressure release functionality, ensuring safe and reliable coolant system performance.

Crafted from high-quality billet aluminum, this reservoir cap offers superior durability and resistance to heat and fluids, preventing warping or degradation over time. Unlike adhesive-based cap covers that can loosen or fall off, this cap is a direct replacement for the factory component, providing a secure, high-performance solution.

  • OEM pressure release functionality – Maintains proper system regulation for optimal coolant performance
  • Premium billet aluminum construction – Offers enhanced durability and longevity
  • Direct replacement design – Secure fit without adhesives or modifications
  • Resistant to heat and fluids – Ensures long-lasting reliability in extreme conditions
  • Performance-inspired look – Adds a sleek, high-end appearance to your engine bay
  • Upgraded durability – Prevents cracking, leaks, and premature wear

Upgrade your BMW’s cooling system with the BMW Black Auxiliary Coolant Reservoir Cap, blending performance, reliability, and premium styling.

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Precision Raceworks - Corporate Logo
T#:47679259
Part#: 622-0291-SIL
Ships in 9 Business Days
$ 184.99 USD
Free Shipping on orders $49 and up
$ 184.99 USD
Free Shipping on orders $49 and up
The Precision Raceworks Billet Coolant Cap Set is a functional and stunningly stylish way to add a nice touch to any engine bay! These caps come in three color options, so there is always a color that will work for you! Black with Billet Silver, Black with Blue, and the Stealth series (all black). Many people don't realize it, but the OEM caps have a pressure release valve built into them. Oftentimes, aftermarket companies don't know this either or just don't care. But our team cares about proper function just as much as we care about the appearance of every product we design. For pressure relief, our caps incorporate the OEM internals, so you get all the functionality of the original caps, ensuring a safe and reliable system in place. These caps offer superior style and performance-grade components that guarantee a reliable fit every time. Durable billet aluminum construction provides long-lasting protection and dependability that will upgrade your engine bay for years to come. PLEASE NOTE: These do require assembly and swapping the pressure relief valves from your old caps to your new billet caps.
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Precision Raceworks - Corporate Logo
T#:47679257
Part#: 622-0291-BLAK
Ships in 9 Business Days
$ 184.99 USD
Free Shipping on orders $49 and up
$ 184.99 USD
Free Shipping on orders $49 and up
The Precision Raceworks Billet Coolant Cap Set is a functional and stunningly stylish way to add a nice touch to any engine bay! These caps come in three color options, so there is always a color that will work for you! Black with Billet Silver, Black with Blue, and the Stealth series (all black). Many people don't realize it, but the OEM caps have a pressure release valve built into them. Oftentimes, aftermarket companies don't know this either or just don't care. But our team cares about proper function just as much as we care about the appearance of every product we design. For pressure relief, our caps incorporate the OEM internals, so you get all the functionality of the original caps, ensuring a safe and reliable system in place. These caps offer superior style and performance-grade components that guarantee a reliable fit every time. Durable billet aluminum construction provides long-lasting protection and dependability that will upgrade your engine bay for years to come. PLEASE NOTE: These do require assembly and swapping the pressure relief valves from your old caps to your new billet caps.
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Canton Racing - Corporate Logo
T#:19428688
Part#: 80-272BLK
Ships on Aug 12, 2026
$ 223.00 USD
Free Shipping on orders $49 and up

Upgrade your Gen1 Mini Cooper or Cooper S with the coolant expansion/fill tank featuring a billet radiator-style neck. This tank accepts the Canton Racing part #81-030 pressure cap or any 30 psi radiator-style cap. The Canton Racing Aluminum tank with Powdercoated Wrinkle Black finish not only enhances the engine bay aesthetics but also resolves expansion tank issues with its solid build and built-in mount. Say goodbye to concerns about separating and leaking plastic expansion tanks. Pair it with the Canton Racing 77-272 MINI power steering tank for a perfect combination.

  • Features a billet radiator-style neck
  • Accepts Canton Racing pressure cap or any 30 psi radiator-style cap
  • Enhances engine bay aesthetics with Powdercoated Wrinkle Black finish
  • Resolves expansion tank issues with solid build and built-in mount
  • Eliminates worries about separating and leaking plastic tanks
  • Perfect complement to Canton Racing 77-272 MINI power steering tank
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Canton Racing - Corporate Logo
T#:31390597
Part#: 80-272BLKKT
Ships on Aug 12, 2026
$ 261.00 USD
Free Shipping on orders $49 and up

MINI R50 to R53 Expansion Tank Aluminum Wrinkle Black & Cap - Kit offers the premium quality of Canton Racing for MINI enthusiasts. This high-grade aluminum expansion tank features a sleek Wrinkle Black powder-coated finish, designed to replace the original plastic tank with ease.

  • Premium Quality: Made from durable aluminum with a Wrinkle Black powder-coated finish for enhanced aesthetics and longevity.
  • Direct Replacement: Utilizes the original mountings for a hassle-free installation, ensuring a perfect fit.
  • Enhanced Functionality: Upgrades from the standard plastic tank to improve both appearance and performance over time.
  • Kit Includes:
    • Canton Racing Coolant Tank in Wrinkle Black Powdercoating
    • Canton Racing Stant Tank Cap
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Canton Racing - Corporate Logo
T#:31423679
Part#: 80-272BLKKT1KT
Ships on Aug 12, 2026
$ 479.00 USD
Free Shipping on orders $49 and up

MINI R50 to R53 Expansion Tank / Power Steering Tank - Wrinkle Black Aluminum is a high-quality solution designed to address both coolant expansion and power steering needs in one kit. This kit includes a billet-style expansion tank with a radiator neck that accepts the Canton Racing part #81-030 pressure cap or any 30 psi radiator cap, ensuring a secure and leak-proof seal.

Key benefits of the MINI R50 to R53 Expansion Tank / Power Steering Tank - Wrinkle Black Aluminum include:

  • Dual Functionality: Combines both expansion tank and power steering tank into a single, convenient kit.
  • Durable Construction: Made from aluminum with a wrinkle black finish, providing long-lasting performance and a sleek appearance.
  • Enhanced Sealing: Features a billet radiator-style neck that fits standard 30 psi radiator caps, preventing leaks and ensuring reliable operation.
  • Reliable Design: Eliminates the issues associated with plastic tanks, such as separation and leakage.
  • Complete Kit: Includes a black expansion tank, black power steering tank, and a Stant cap for easy installation.
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Bavarian Autosport - Corporate Logo
T#:640491
Part#: 17137542986
Special Order: No Guaranteed ETA
Sale - Save 10% $ 54.99

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

$ 49.49 USD
Free Shipping on orders $49 and up
Sale - Save 10%
$ 54.99

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

$ 49.49 USD
Free Shipping on orders $49 and up
This Bav Auto cooling system expansion tank/coolant reservoir is a direct replacement for the factory unit. Replace your cracked or leaking radiator expansion tank today. 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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