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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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Mahle-Behr - Corporate Logo
T#:341101
Part#: 17111723520
In Stock at Vendor
$ 97.62

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

$ 77.22 USD
Free Shipping on orders $49 and up
$ 77.22 USD
Free Shipping on orders $49 and up
Hailing from Stuttgart, Mahle-Behr specializes in automotive cooling systems. From air conditioning to engine cooling M-B has you covered with OE-quality replacement parts.
E36 Mishimoto Black Aluminum Coolant Expansion Tank
Direct fitment with the Mishimoto fan shroud. Modification may be required with the OEM shroud.
Mishimoto - Corporate Logo
T#:383861
Part#: MMRT-E36-92EBK
Back Ordered
$ 195.99 USD
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$ 195.99 USD
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The coolant expansion tank in your vehicle gives additional fluid a place to go after expansion and contraction from temperature change. Because it is subjected to such drastic changes on a regular basis, it can often crack or break. You want to keep all the coolant in your vehicle in the cooling system. If your tank has experienced damage such as cracking, nipples breaking off, or mounting point damage, you will need to replace it. Mishimoto provides a one time fix for this issue with their new aluminum expansion tank. Features: Constructed from aluminum to prevent future cracking Multi function aluminum dipstick w/ knurled head Utilizes factory mounting points, hardware, and sensor (s) Can be used with either Mishimoto or OEM radiator And of course this product come with Mishimoto's lifetime warranty WARNING! Prog 65 may apply to this product.Proposition 65 (Safe Drinking Water and Toxic Enforcement Act of 1968) is a California law that applies to call companies selling products in California. Prop 65 requires any listed chemical present above very low levels that are known to cause cancer, birth defects, or other reproductive harm.For more information about California Prop 65 warning see: www.P65Warnings.ca.gov.
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MMX Performance - Corporate Logo
T#:29002094
Part#: MMR03-1502
Ships in 3 Business Days
$ 127.99 USD
Free Shipping on orders $49 and up
The MMX Performance 90mm billet coolant expansion cap for BMWs has been designed from the ground up in the UK, from a solid piece of billet aluminum. Each cap was designed to directly replace the OE cap, not merely stuck in place. Fitment is for models with the matching OE (17 11 7 639 021) part number.
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Vargas Turbo Technologies - Corporate Logo
T#:7530035
Part#: COOLANTCAPRAW
Back Ordered
$ 78.99 USD
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$ 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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Moroso - Corporate Logo
T#:29666105
Part#: 63851
In Stock at Vendor
$ 488.99 USD
Free Shipping on orders $49 and up

The coolant expansion tank provides hot coolant with a place to travel, preventing pressure buildup within your cooling system. On many BMWs, this component is constructed from plastic. While cheap to replace and manufacture, a failed cooling tank can cause costly engine damage.

With this issue in mind, Moroso designed a high-quality replacement. Featuring TIG welded, 100% aluminum construction, this tank is sure to outperform it's factory counterpart.

Features:

Key Benefits:

Direct bolt-in replacement for stock, 2 piece plastic tank Fabricated Aluminum for strength, factory tanks fail after repeated high heat situations & age Features billet aluminum mounting tab/bleeder assembly for strength and precision No cutting of factory hoses is required and accepts the factory clip-on hose Moroso part (63324) racing radiator cap included; operates in the same pressure range as the factory cap Moroso radiator cap mounts to a billet aluminum neck that will not strip out like plastic threaded necks This aluminum tank can be polished, chromed, powder coated or left as-is

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Goldenwrench Supply Co - Corporate Logo
T#:641288
Part#: FXXCET
In Stock
$ 65.00 USD
Free Shipping
$ 65.00 USD
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Give the plain plastic factory coolant caps an upgrade with the brand new BLACKLINE Performance Coolant Expansion Tank Cap Cover from Goldenwrench. Each cap is CNC formed from T6 Aluminum and anodized with an Anthracite Gray color to compliment the factory engine cover. All logos and decorations are finalized through a precision 3D milling process, machined into each cap for the ultimate premium finish. The BLACKLINE Performance Billet Coolant Expansion Tank Cap Cover will fit most BMW vehicles equipped with the N55, S55, S63, and S65 engine with the large coolant tank found in the following vehicles E90/E91/E92 M3 LCI, F22 M235i, F87 M2/M2 Competition, F80 M3, F82 M4, F10/F90 M5, and more (check your coolant cap ensuring that it is the same shape as seen in the product photos). Each kit comes with a Billet Coolant Expansion Tank Cap Cover, and an Installation Instruction Card. This is a not a full cap replacement. The Billet Cap Cover affixes to the top of your factory coolant cap installing easily in minutes.
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URO - Corporate Logo
T#:591954
Part#: 17111707777
Ships in 2 Business Days
$ 6.99 USD
Free Shipping on orders $49 and up
Locks the expansion tank into the mounting plate via the large hole in the bottom of the tank
Mahle-Behr - Corporate Logo
T#:361568
Part#: 17111741167
Ships in 2 Business Days
$ 100.99

This product was last offered at the strikethrough price on
05-07-2026

$ 97.99 USD
Free Shipping
$ 97.99 USD
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This radiator expansion tank (coolant reservoir) is used on E39 540i from 1997-2003 and E38 740i 740il 750il from 1995-2001. It is a common failure item. 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 OEM Hella tank will give you a long life-span and will put your worries to rest of possible failure and coolant loss.

Hella is a premium manufacturer that supplies automotive parts to numerous car brands across the world. Everything from electrical to mechanical genuine parts have been made and supplied directly to BMW before the vehicles ever leave the production floor. Their high quality, long lasting parts have made them a trusted brand chosen to help keep your BMW on the road for many years to come.

As a leading source of high performance BMW parts and accessories since 1993, we at Turner Motorsport are honored to be the go-to supplier for tens of thousands of enthusiasts the world over. With over two decades of parts, service, and racing experience under our belt, we provide only quality performance and replacement parts.  All of our performance parts are those we would (and do!) install and run on our own cars, as well as replacement parts that are Genuine BMW or from OEM manufacturers. We only offer parts we know you can trust to perform!

This item fits the following BMWs:
1997-2003 E39 BMW 540i, 540i wagon
1995-2001 E38 BMW 740i 740il 750il
1990-1998 E31 BMW 840i 840ci 850i 850ci
2000-2003 E52 BMW Z8

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URO - Corporate Logo
T#:380458
Part#: 61311375715
Ships in 2 Business Days
$ 15.99 USD
Free Shipping on orders $49 and up
Replace your coolant level sensor and ensure that your levels are accurately monitored

Genuine BMW - Corporate Logo
T#:7457
Part#: 17117573751
Ships in 1-2 days
2% off MSRP $ 164.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 160.99 USD
Free Shipping
2% off MSRP
$ 164.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 160.99 USD
Free Shipping
This high quality Genuine BMW brand expansion tank is used on M54 and N52 engines, and is a common failure item on all E85 Z4's. Be leary of competitors selling this part for less -- is it a Genuine BMW? Probably not.

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.

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.

This item fits the following BMWs:
2003-2008 E85 BMW Z4 2.5i Z4 3.0i Z4 3.0si
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Moroso - Corporate Logo
T#:568945
Part#: 63793
In Stock at Vendor
$ 433.99 USD
Free Shipping
$ 433.99 USD
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If you have ever experienced a leaking plastic BMW expansion tank you will realize the value of this aluminum version straight away. Even if a failure has not happened to you, it's easy to tell this tank is much stronger and more durable than the plastic used in the stock design. The original BMW plastic tanks suffer from leaks and failures with no warning. While being lightweight and recyclable, the design and construction of the stock tank is just not up for reliable long-term use. Moroso coolant expansion tanks are all pressure tested for guaranteed leak-free operation. Features: Direct bolt-in replacement to stock, cracked, or discolored tanks Fabricated Aluminum for strength, factory tanks fail after repeated high heat situations & age No cutting of factory hoses is required and accepts the factory clip-on hose Included is a Moroso Part No. 63324 racing radiator cap that operates in the same pressure range as the factory cap The Moroso radiator cap mounts to a billet aluminum neck that will not strip out like plastic threaded necks Easy to read slight level is included
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URO - Corporate Logo
T#:377303
Part#: 17107514964
Ships in 2 Business Days
$ 52.30 USD
Free Shipping on orders $49 and up
The coolant expansion tank in your vehicle gives additional fluid a place to go after expansion and contraction from temperature change. Because it is subjected to such drastic changes on a regular basis, it can often crack or break.
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URO - Corporate Logo
T#:373103
Part#: 17137787039
Ships in 2 Business Days
$ 45.99 USD
Free Shipping on orders $49 and up
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.
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URO - Corporate Logo
T#:363421
Part#: 17117573751
Ships in 2 Business Days
$ 64.99 USD
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$ 64.99 USD
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Does not include cap or coolant level sensor
Rein - Corporate Logo
T#:591949
Part#: 17107514964
Back Ordered
$ 80.99 USD
Free Shipping
$ 80.99 USD
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Includes bleeder screw

Meistersatz - Corporate Logo
T#:1195781
Part#: 17117639021
Ships in 4 Business Days
$ 30.99

This product was last offered at the strikethrough price on
07-07-2026

$ 29.99 USD
Free Shipping on orders $49 and up
$ 29.99 USD
Free Shipping on orders $49 and up

URO - Corporate Logo
T#:373099
Part#: 17137516004
Ships in 2 Business Days
$ 15.99

This product was last offered at the strikethrough price on
04-10-2026

$ 10.99 USD
Free Shipping on orders $49 and up
$ 10.99 USD
Free Shipping on orders $49 and up
The coolant expansion tank cap keeps necessary pressure on your coolant to increase efficiency. If you have an overheating issue in your vehicle, a simple, quick, and inexpensive part to replace is this cap.
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Vaico - Corporate Logo
T#:595421
Part#: 17127575428
Ships in 2 Business Days
$ 143.99

This product was last offered at the strikethrough price on
08-12-2026

$ 80.99 USD
Free Shipping on orders $49 and up
$ 80.99 USD
Free Shipping on orders $49 and up
Overflow hoses connect the radiator and the expansion tank to store overflow of coolant. As pressures in the cooling system increase due to coolant temperatures, a valve on the radiator cap permits coolant back into the reservoir to help ease the build-up of pressure and prevent coolant loss. If your hose is leaking or damaged, we recommend swapping it out with this replacement from Vaico.
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Rein - Corporate Logo
T#:38229110
Part#: 17138617045
Ships in 4 Business Days
$ 73.99 USD
Free Shipping on orders $49 and up

Charge Air Cooler Expansion Tank - Rein | BMW F22/23, F3X B48/B46 B58 is an essential component that ensures proper coolant circulation in the charge air cooling system. Acting as a reservoir, this expansion tank allows coolant to expand and contract with temperature fluctuations, preventing excessive pressure buildup. Over time, plastic tanks can become brittle due to constant exposure to heat cycles, leading to cracks and leaks. A failing tank can cause coolant loss, reducing the efficiency of the charge air cooler and leading to increased intake temperatures, which negatively impact horsepower and engine performance. Rein offers a high-quality direct replacement designed for durability and a perfect fit on BMW F22, F23, and F3X models with B48, B46, and B58 engines.

  • Maintains proper coolant circulation within the charge air cooling system
  • Prevents excessive pressure buildup caused by temperature fluctuations
  • Durable construction resists cracking and leaks for long-lasting performance
  • Direct replacement for BMW F22, F23, and F3X models with B48, B46, and B58 engines
  • Helps maintain optimal intake air temperatures, preserving horsepower and efficiency
  • OE-quality fitment ensures hassle-free installation and reliable function
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Rein - Corporate Logo
T#:592015
Part#: 17137501959
Ships in 3 Business Days
$ 74.99 USD
Free Shipping
$ 74.99 USD
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Includes vent screw and leveling switch

Mahle-Behr - Corporate Logo
T#:369633
Part#: 17111742232
Ships in 2 Business Days
$ 18.99 USD
Free Shipping on orders $49 and up
$ 18.99 USD
Free Shipping on orders $49 and up
This radiator expansion tank cap fits E30 325e 325es 325i 325is 325ix 325ic with M20 engine from 1988 . 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.

This item fits the following BMWs:
1988-1991  E30 BMW  325e 325es 325i 325ic 325is 325ix
1989-1990  E34 BMW  525i with M20 engine
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URO - Corporate Logo
T#:373093
Part#: 11531711002
Back Ordered
$ 41.99 USD
Free Shipping on orders $49 and up
Connects between the thermostat and the lower expansion tank then to the heater core
URO - Corporate Logo
T#:362007
Part#: 17114379047
Back Ordered
$ 7.99 USD
Free Shipping on orders $49 and up
$ 7.99 USD
Free Shipping on orders $49 and up
1.2 Bar pressure
URO - Corporate Logo
T#:362912
Part#: 17111436251
Back Ordered
$ 53.99 USD
Free Shipping on orders $49 and up
$ 53.99 USD
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Mounts to the side of the radiator for retaining the expansion tank


URO - Corporate Logo
T#:377312
Part#: 17137543003
Ships in 2 Business Days
$ 56.99 USD
Free Shipping on orders $49 and up
The coolant expansion tank in your vehicle gives additional fluid a place to go after expansion and contraction from temperature change. Because it is subjected to such drastic changes on a regular basis, it can often crack or break. You want to keep all the coolant in your vehicle in the cooling system. If your tank has experienced damage such as cracking, nipples breaking off, or mounting point damage, you will need to replace it.
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Rein - Corporate Logo
T#:593074
Part#: 17137601948
Ships in 4 Business Days
$ 118.99 USD
Free Shipping
$ 118.99 USD
Free Shipping
Cooling system expansion tank
URO - Corporate Logo
T#:592016
Part#: 17137552546
Ships in 2 Business Days
$ 70.99 USD
Free Shipping on orders $49 and up
Replace your cracked or faded tank

Genuine BMW - Corporate Logo
T#:2062
Part#: 17111719110
Ships in 1-2 days
2% off MSRP $ 164.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 160.99 USD
Free Shipping
2% off MSRP
$ 164.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 160.99 USD
Free Shipping
This radiator expansion tank is used on E34 530i 540i from 1993-1995 and E32 740i 740il 750il from 1988-1994. It is a common failure item. If you are overhauling your coolant system, now is the time to consider preventative replacing this expansion tank.

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.

This item fits the following BMWs:
1992-1995 E34 BMW 530i 540i
1988-1994 E32 BMW 740i 740il 750il
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Rein - Corporate Logo
T#:592018
Part#: 17137639023
Ships in 4 Business Days
$ 14.99 USD
Free Shipping on orders $49 and up
$ 14.99 USD
Free Shipping on orders $49 and up
1.4 Bar pressure
URO - Corporate Logo
T#:373098
Part#: 64218390710
Ships in 2 Business Days
$ 21.99 USD
Free Shipping on orders $49 and up
Connects to coolant recovery tank

URO - Corporate Logo
T#:593075
Part#: 17137647281
Ships in 2 Business Days
$ 59.99 USD
Free Shipping on orders $49 and up
The coolant expansion tank in your vehicle gives additional fluid a place to go after expansion and contraction from temperature change. Because it is subjected to such drastic changes on a regular basis, it can often crack or break.
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Genuine BMW - Corporate Logo
T#:12560
Part#: 17111436251
In Stock
3% off MSRP $ 112.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 109.99 USD
Free Shipping
3% off MSRP
$ 112.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 109.99 USD
Free Shipping
This Genuine BMW part is the mounting bracket from the radiator to the expansion tank on E46 3 series and E85/E86 Z4 with Automatic Transmission.

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.

This item fits the following BMWs:
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi
2003-2008 E85 BMW Z4 2.5i Z4 3.0i Z4 3.0si
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Rein - Corporate Logo
T#:402421
Part#: 17113400017
Ships in 4 Business Days
$ 166.99 USD
Free Shipping
$ 166.99 USD
Free Shipping
Secures the expansion tank to the radiator

Rein - Corporate Logo
T#:592030
Part#: 17138621092
In Stock at Vendor
$ 100.99 USD
Free Shipping
$ 100.99 USD
Free Shipping
Replace your cracked or faded tank
Febi Expansion Tank Mounting Plate - E83
We Price Match - Give Us A Call or Chat!
Febi - Corporate Logo
T#:1196172
Part#: 17113400017
In Stock at Vendor
$ 95.99

This product was last offered at the strikethrough price on
05-07-2026

$ 92.99 USD
Free Shipping
$ 92.99 USD
Free Shipping
Secures the expansion tank to the radiator
URO - Corporate Logo
T#:20203
Part#: 61318360876
Ships in 2 Business Days
$ 12.99

This product was last offered at the strikethrough price on
04-10-2026

$ 10.99 USD
Free Shipping on orders $49 and up
$ 10.99 USD
Free Shipping on orders $49 and up
This is the radiator coolant level sensor that mounts into the bottom of the cooling system expansion tank. With more than 4,000 European vehicle replacement parts, URO is no stranger to the market. Superior metal stock and extremely strict quality control are at the forefront of URO’s agenda and it shows as they become the OE supplier for more and more car companies every single day.

With more than 4,000 European vehicle replacement parts, URO is no stranger to the market. Superior metal stock and extremely strict quality control are at the forefront of URO’s agenda and it shows as they become the OE supplier for more and more car companies every single day.​

This item fits the following BMWs:
1999-2000 E39 BMW 528i 540i
2001-2003 E39 BMW 525i 530i 540i
1995-2001 E38 BMW 740i 740il 750il
1990-1998 E31 BMW 840i 840ci
2000-2003 E52 BMW Z8 Roadster
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AUTOTECKNIC - Corporate Logo
T#:39497984
Part#: BM-0803-GC
Ships in 8 Business Days
$ 74.99 USD
Free Shipping on orders $49 and up
Turner Motorsport offers the AutoTecknic Dry Carbon Coolant Expansion Tank Cap Cover - Gloss Carbon as the perfect addition for BMW owners looking to elevate their engine bay’s appearance with premium materials and precision engineering.
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URO - Corporate Logo
T#:373100
Part#: 17111436381
Ships in 2 Business Days
$ 57.99 USD
Free Shipping on orders $49 and up
BMW E39 coolant expansion tank without cap.
Mahle-Behr - Corporate Logo
T#:592026
Part#: 17138570079
Ships in 2 Business Days
$ 139.00

This product was last offered at the strikethrough price on
03-20-2026

$ 103.99 USD
Free Shipping
$ 103.99 USD
Free Shipping
Includes level sensor

URO - Corporate Logo
T#:597578
Part#: 17138614293
Ships in 2 Business Days
$ 65.99

This product was last offered at the strikethrough price on
05-07-2026

$ 56.99 USD
Free Shipping on orders $49 and up
$ 56.99 USD
Free Shipping on orders $49 and up
A quality replacement from URO. Includes level sensor

URO - Corporate Logo
T#:362010
Part#: 17137501959
Ships in 2 Business Days
$ 53.99 USD
Free Shipping on orders $49 and up
Includes vent screw and leveling switch
Rein - Corporate Logo
T#:555023
Part#: 17138570079
Ships in 4 Business Days
$ 124.99 USD
Free Shipping
$ 124.99 USD
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Replace your damaged expansion tank to prevent coolant loss or potential overheating issues.


This item fits the following BMW Chassis:
E90

Fits BMW Engines including:
M57

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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
Free Shipping
Starting at $ 77.22 USD
Free Shipping
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#:27605427
Part#: 17138677649TKT
Ships in 2 Business Days
Sale - Save 4% $ 208.99

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

$ 200.88 USD
Free Shipping on orders $49 and up
Sale - Save 4%
$ 208.99

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

$ 200.88 USD
Free Shipping on orders $49 and up
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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Moroso - Corporate Logo
T#:29666103
Part#: 63799
In Stock at Vendor
$ 459.99 USD
Free Shipping on orders $49 and up

The coolant expansion tank provides hot coolant with a place to travel, preventing pressure buildup within your cooling system. On many BMWs, this component is constructed from plastic. While cheap to replace and manufacture, a failed cooling tank can cause costly engine damage.

With this issue in mind, Moroso designed a high-quality replacement. Featuring TIG welded, 100% aluminum construction, this tank is sure to outperform it's factory counterpart.

Features:

Bolt-in replacement for stock cracked or discolored tanks Fabricated aluminum Features billet aluminum filler neck and integrated sight glass to monitor coolant level Can be polished, painted, powder coated or left as-is Moroso radiator cap (63320) included

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Rein - Corporate Logo
T#:402160
Part#: 17137542986
Ships in 2 Business Days
$ 82.99 USD
Free Shipping
$ 82.99 USD
Free Shipping
Includes fluid level sensor
Febi - Corporate Logo
T#:27405536
Part#: 17138617045
Ships in 2 Business Days
$ 101.99

This product was last offered at the strikethrough price on
05-08-2026

$ 100.99 USD
Free Shipping on orders $49 and up
$ 100.99 USD
Free Shipping on orders $49 and up
Your charge air cooler's coolant expansion tank acts as a reservoir, housing extra coolant, and gives fluid a place to go after expansion and contraction from temperature change. Because the plastic tank is subjected to regular temperature changes, the plastic can become brittle over time and will often crack or break. If your tank is leaking and you lose too much coolant, your charge air cooler will not function properly and your air intake temperatures will begin to rise, reducing horsepower and efficiency. If your tank has experienced damage such as cracking, nipples breaking off, or mounting point damage, you will need to replace it.
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Meyle - Corporate Logo
T#:5704977
Part#: 17138677649
Ships in 2 Business Days
$ 164.99

This product was last offered at the strikethrough price on
03-20-2026

$ 123.99 USD
Free Shipping
$ 123.99 USD
Free Shipping
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 fewer than six to eight 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.
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URO - Corporate Logo
T#:639209
Part#: 17138610656
Ships in 2 Business Days
$ 117.99 USD
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Replace your leaky coolant tank!
Coolant Expansion Tank
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Febi - Corporate Logo
T#:16242201
Part#: 17137590626
In Stock at Vendor
$ 123.99

This product was last offered at the strikethrough price on
05-08-2026

$ 120.99 USD
$ 120.99 USD