Find Parts That Fit Your Vehicle

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.
Sort By:

Coolant Expansion Tank - E46 (non-M), X3, X5 3.0
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:338020
Part#: 17117573781
In Stock at Vendor
Sale - Save 9% $ 140.99

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

Starting at $ 128.98 USD
Free Shipping
Sale - Save 9%
$ 140.99

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

Starting at $ 128.98 USD
Free Shipping
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
Show More Show Less
Coolant Expansion Tank - E36/E39/Z3 6 cylinder 1992-1998
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:338018
Part#: 17111723520
Ships in 1 Business Day
$ 97.99

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

Starting at $ 63.18 USD
Free Shipping
Starting at $ 63.18 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)
Show More Show Less
Expansion Tank Replacement Kit - E60 M5,E63 M6
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:584232
Part#: 17112283345KT
In Stock
$ 250.99 USD
Free Shipping
$ 250.99 USD
Free Shipping
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.
Show More Show Less

Mahle-Behr - Corporate Logo
T#:350824
Part#: 17137640514
Ships in 1 Business Day
$ 130.99

This product was last offered at the strikethrough price on
08-17-2026

$ 112.99 USD
Free Shipping
$ 112.99 USD
Free Shipping

Upgrade your BMW's cooling system with the Turner Motorsport Mahle Coolant Expansion Tank. This essential component provides additional space for coolant expansion and contraction, ensuring optimal performance in varying temperatures. Designed to withstand drastic temperature changes, this expansion tank prevents coolant leaks and maintains proper coolant levels in your vehicle. Replace your damaged tank to keep your BMW's cooling system running smoothly.

Key Benefits:

  • Prevents coolant leaks and loss
  • Ensures proper coolant expansion and contraction
  • Durable construction for long-lasting performance
  • Direct replacement for damaged tanks
  • Compatible with various BMW models
Show More Show Less

Moroso - Corporate Logo
T#:568945
Part#: 63793
In Stock at Vendor
$ 433.99 USD
Free Shipping
$ 433.99 USD
Free Shipping
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
Show More Show Less
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
In Stock
$ 195.99 USD
Free Shipping
$ 195.99 USD
Free Shipping
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.
Show More Show Less

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

$ 88.99 USD
Free Shipping
$ 88.99 USD
Free Shipping

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

Show More Show Less
Mahle-Behr - Corporate Logo
T#:340674
Part#: 17137542986
Ships in 1-2 days
$ 137.95

This product was last offered at the strikethrough price on
08-13-2026

$ 133.10 USD
Free Shipping
$ 133.10 USD
Free Shipping
This Behr OEM cooling system expansion tank / coolant reservoir is a direct replacement for the factory unit. Replace your cracked or leaking radiator expansion tank today.

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.​

This item fits the following BMWs:
2004-2010  E60 BMW  525i 525xi 530i 530xi 528i 528xi 528i xDrive 535i 535xi 535i xDrive 545i 550i
2004-2010  E63 BMW  645ci 650i
Show More Show Less

Mahle-Behr - Corporate Logo
T#:592026
Part#: 17138570079
Ships in 1 Business Day
$ 139.00

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

$ 114.99 USD
Free Shipping
$ 114.99 USD
Free Shipping
Includes level sensor

Mahle-Behr - Corporate Logo
T#:377924
Part#: 17137552546
Ships on Sep 18, 2026
$ 85.99 USD
Free Shipping
$ 85.99 USD
Free Shipping
Replace your cracked or faded tank
Meyle Coolant Expansion Tank - F22/23 230/M240, F3X 330/340/430/440 B...
5X Entries Into Our F80 M3 Sweepstakes
We Price Match - Give Us A Call or Chat!
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.
Show More Show Less
Genuine MINI - Corporate Logo
T#:393093
Part#: 17137823626
Ships in 4 Business Days
7% off MSRP $ 129.99

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

$ 120.99 USD
Free Shipping
7% off MSRP
$ 129.99

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

$ 120.99 USD
Free Shipping


Mahle-Behr - Corporate Logo
T#:186486
Part#: 17137647713
Ships on Sep 18, 2026
$ 81.99 USD
Free Shipping
$ 81.99 USD
Free Shipping
This high quality BEHR brand expansion tank is used on E65/E66 7 series with the N62 and N73 engines, and is a common failure item. BEHR was the original equipment supplier to BMW, so you know the BEHR made expansion tank will be the highest quality available. Be cautious 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. Replaces part numbers 17137543003 and 17138600275.

This item fits the following BMWs:
2002-2008 E65 BMW 745i 745li 750i 750li 760i 760li
Show More Show Less