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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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Coolant Expansion Tank - E46 (non-M), X3, X5 3.0

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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
04-01-2026

Starting at $ 137.98 USD

Add to Wish List

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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Coolant Expansion Tank - E36/E39/Z3 6 cylinder 1992-1998

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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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Expansion Tank Replacement Kit - E60 M5,E63 M6

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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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BMW E9X Z4 E8X Coolant Expansion Tank

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T#:402142

Part#: 17137640514

In Stock

$ 70.99

This product was last offered at the strikethrough price on
06-22-2026

$ 70.35 USD

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$ 70.35 USD

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Includes level sensor

Coolant Expansion Tank

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T#:592020

Part#: 17137640515

In Stock

$ 97.99 USD

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$ 97.99 USD

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Includes level sensor

Rein Coolant Expansion Tank - E46, E53, E83

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T#:402141

Part#: 17117573781

In Stock

$ 76.39 USD

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$ 76.39 USD

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Includes cap and level sensor

Rein Expansion Tank Mounting Plate - E46, Z4

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T#:402139

Part#: 17111436251

Ships in 1 Business Day

$ 80.99 USD

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$ 80.99 USD

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Mounts to the side of the radiator for retaining the expansion tank

OEM Rein Expansion Tank - F01,F06,F10,F12,F13

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T#:555024

Part#: 17137647283

In Stock

$ 118.99 USD

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$ 118.99 USD

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Replace your damaged expansion tank to prevent coolant loss or potential overheating issues.

his item fits the following BMW Chassis:
F01,F02,F06,F10,F12,F13

Fits BMW Engines including:
N54,N55,N57N

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Coolant Expansion Tank

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T#:591959

Part#: 17111741167

Ships in 1 Business Day

$ 69.99 USD

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$ 69.99 USD

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Plastic has a limited lifespan - replace every 80,000 miles

Expansion Tank Mounting Plate

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T#:402140

Part#: 17111436250

In Stock

$ 70.99 USD

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$ 70.99 USD

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BMW E39 Coolant Expansion Tank

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T#:388645

Part#: 17111436381

In Stock

$ 87.99 USD

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$ 87.99 USD

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BMW E39 Coolant Expansion Tank is an essential component designed to maintain the proper coolant level in your vehicle's cooling system. Manufactured with high-quality materials, this expansion tank ensures reliable performance and durability, preventing engine overheating by accommodating the expansion of coolant as it heats up. The kit includes a level sensor and cap, providing everything needed for a seamless installation. This expansion tank is specifically engineered to meet the exact specifications of your BMW E39, offering a perfect fit and optimal functionality.

Complete Kit: Includes level sensor and cap for easy installation.
High-Quality Construction: Built with durable materials for long-lasting performance.
Prevents Overheating: Helps manage coolant expansion, ensuring engine protection.
Exact Fit: Designed to meet the precise specifications of your BMW E39.
Enhanced Reliability: Ensures proper coolant level maintenance for optimal cooling system function.

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Coolant Expansion Tank

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T#:388723

Part#: 17137823626

In Stock

$ 78.99 USD

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$ 78.99 USD

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Mounts towards the front of the engine bay

Expansion Tank

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T#:592015

Part#: 17137501959

Ships in 2 Business Days

$ 74.99 USD

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Qty

$ 74.99 USD

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Includes vent screw and leveling switch

Rein Coolant Expansion Tank - E70

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T#:592030

Part#: 17138621092

Ships in 1 Business Day

$ 100.99 USD

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Qty

$ 100.99 USD

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Replace your cracked or faded tank

Coolant Expansion Tank

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T#:591949

Part#: 17107514964

Ships in 3 Business Days

$ 80.99 USD

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$ 80.99 USD

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Includes bleeder screw

OEM Rein Expansion Tank - E90 335d

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T#:555023

Part#: 17138570079

Ships in 3 Business Days

$ 124.99 USD

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$ 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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Rein Expansion Tank Mounting Plate - E83

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T#:402421

Part#: 17113400017

Ships in 3 Business Days

$ 166.99 USD

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$ 166.99 USD

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Secures the expansion tank to the radiator

Expansion Tank

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T#:593074

Part#: 17137601948

Back Ordered

$ 118.99 USD

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$ 118.99 USD

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Cooling system expansion tank

Intercooler Expansion Tank

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T#:584477

Part#: 17137647281

Ships in 3 Business Days

$ 71.99 USD

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$ 71.99 USD

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Rein Coolant Expansion Tank - E60, E61, E63, E64

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T#:402160

Part#: 17137542986

Ships in 1 Business Day

$ 82.99 USD

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$ 82.99 USD

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Includes fluid level sensor

Rein Coolant Expansion Tank - E65, E66

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T#:593077

Part#: 17137647713

Ships in 3 Business Days

$ 99.99 USD

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$ 99.99 USD

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Replace your cracked or faded tank

Rein Coolant Expansion Tank - E70

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T#:592023

Part#: 17137647290

Ships in 3 Business Days

$ 85.99 USD

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$ 85.99 USD

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Plastic expansion tanks have a limited lifespan - replace every 80,000 miles

Expansion Tank Mounting Plate

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T#:591946

Part#: 17101439110

Ships in 3 Business Days

$ 80.99 USD

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$ 80.99 USD

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