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BMW Coolant Expansion Tanks for BMW 3 Series E46 (1999-2005)

Clear BMW chassis

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

10X Entries Into Our F80 M3 Sweepstakes

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

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Sale - Save 9%

$ 140.99

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

Starting at $ 128.98 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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ECS Cooling System Refresh Kit - Level 1

10X Entries Into Our F80 M3 Sweepstakes

T#:15677493

Part#: 11517527910-KT

In Stock

Sale - Save 4% $ 336.99

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

$ 324.43 USD

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Sale - Save 4%

$ 336.99

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

$ 324.43 USD

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Stop the problems before they arise. If you vehicle has 80,000 miles or more, replace all of these components to ensure that your vehicle stays healthy. To keep everything in top order, continue to replace these components at 80,000 mile intervals. Water pump failure, cracked plastic housings, and expansion tank leaks will not be a concern once all these problem parts are replaced. This kit was put together by Turner including the basic parts that need replaced. Water pump with metal impeller Fan switch Thermostat and thermostat housing Sealing gaskets Expansion tank with level sensor, clamp and cap 1 Gallon Coolant Upper & lower radiator hoses

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ECS Cooling System Refresh Kit - Level 2

10X Entries Into Our F80 M3 Sweepstakes

T#:15677514

Part#: 11281706545-KT

In Stock

Sale - Save 3% $ 474.99

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

$ 460.24 USD

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Qty

Sale - Save 3%

$ 474.99

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

$ 460.24 USD

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Stop the problems before they arise. If your BMW has 80,000 miles or more, replace all of these components to ensure that your vehicle stays healthy. Avoid water pump failure, cracked thermostat housings, and expansion tank leaks, which all lead to overheating and subsequent damage. This kit was put together by Turner for a complete cooling system service. GEBA water pump with metal impeller ECS aluminum water pump pulley Fan switch Thermostat and thermostat housing Sealing gaskets Expansion tank with level sensor, clamp and cap 1 Gallon Coolant Upper & lower radiator hoses Accessory drive belts Radiator drain plug

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Cooling System Refresh Kit - Level 2

10X Entries Into Our F80 M3 Sweepstakes

T#:15744066

Part#: 11287837898-KT

Ships on Dec 7, 2026

Sale - Save 26% $ 808.99

This product was last offered at the strikethrough price on
07-15-2026

$ 596.54 USD

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Qty

Sale - Save 26%

$ 808.99

This product was last offered at the strikethrough price on
07-15-2026

$ 596.54 USD

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BMW has been designing notoriously failure-prone cooling systems since the late 1980s. The coolant capacity in most BMW engines is not sufficient to accommodate any driving or overheating near red zone temperatures. After the gauge reaches this critical area, it is common for thousands of dollars in damage to occur. Stop the problems before they arise. If your vehicle has 80,000 miles or more, replace all of these components to ensure that your vehicle stays healthy. To keep everything in top order, continue to replace these components at 80,000 mile intervals. Water pump failure, cracked housings, and expansion tank leaks will not be a concern once all these problem parts are replaced. Saleri water pump with metal impeller ECS aluminum water pump pulley Fan switch Vaico Q+ thermostat - made in Germany! Sealing gaskets Expansion tank with level sensor, clamp and cap 1 Gallon Coolant Upper & lower radiator hoses Accessory drive belts Radiator drain plug

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Genuine BMW Expansion Tank Cap - E3X / E53 / Z4

T#:207187

Part#: 17117639022

In Stock

21% off MSRP $ 34.96

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

$ 27.67 USD

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21% off MSRP

$ 34.96

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

$ 27.67 USD

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Genuine BMW Radiator Cap - 2,0Bar
This item fits the following BMW Chassis:
E36 M3,E39 M5,E46 M3,E85 Z4M,E53 48IS,E36,E38,E39,E46,E53 X5,E65,E83 X3,E85 Z4,E86 Z4,F06,F10,F12,F13

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Genuine BMW Coolant Expansion Tank - E53 X5, E46 M52/54, E83 X3 ...

T#:360752

Part#: 17117573781

In Stock

$ 173.21 USD

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$ 173.21 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.

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Genuine BMW Coolant Expansion Tank - E46 M3

T#:13185

Part#: 17112283344

In Stock

7% off MSRP $ 215.23

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

$ 199.98 USD

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Qty

7% off MSRP

$ 215.23

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

$ 199.98 USD

Add to Wish List

This radiator coolant reservoir/expansion tank for E46 M3 is a common failure item as the plastic weakens over time and stress crack will lead to coolant leaks. If your car has over 80k miles and hasn't had one of these replaced, we highly recommend it during your next major service. We have found that the aftermarket coolant reservoirs fail easier than the original BMW piece so we only offer the BMW type on this part.

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:
2001-2006 E46 BMW M3

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Genuine BMW - Expansion Tank Replacement Kit - Level 1

T#:374557

Part#: 17117573781OEKT

In Stock

$ 273.99 USD

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$ 273.99 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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Expansion Tank Mounting Bracket - E46 - Manual Trans

For vehicles with manual transmission only

T#:13180

Part#: 17111436250

Ships in 3 Business Days

2% off MSRP $ 134.99

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

$ 131.99 USD

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Qty

2% off MSRP

$ 134.99

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

$ 131.99 USD

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This Genuine BMW part is the mounting bracket from the radiator to the expansion tank on E46 3 series Manual 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

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Genuine BMW Cap - 17121719356 - E30,E46,E46 M3

T#:46115

Part#: 17121719356

Ships in 5 Business Days

3% off MSRP $ 31.99

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

$ 30.99 USD

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Qty

3% off MSRP

$ 31.99

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

$ 30.99 USD

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Genuine BMW Cap
This item fits the following BMW Chassis:
E46 M3,E30,E46

Fits BMW Engines including:
M20,S54,S62

Expansion Tank Mounting Bracket - E46 E85 Z4 - Auto Trans

For vehicles with automatic transmission only

T#:12560

Part#: 17111436251

In Stock

Sale - Save 51% $ 205.99

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

$ 101.32 USD

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Qty

Sale - Save 51%

$ 205.99

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

$ 101.32 USD

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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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Genuine BMW - Level 1 Expansion Tank Replacement Kit - E46 M52,M54 ...

T#:380426

Part#: 17117573781OEKT1

Ships in 3 Business Days

$ 589.99

This product was last offered at the strikethrough price on
07-10-2026

$ 499.99 USD

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$ 499.99 USD

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