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BMW Cooling System Parts & Accessories for BMW Z Series E85/6 (2003-2008)

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The cooling system is arguably the weakest point in numerous BMWs. If you drive an aging BMW or plan on taking your car to the track like we do, we recommend beefing up your cooling system before going to the track. Generally, the main components in your cooling system that are prone to failure include the following: expansion tank, factory hoses, water pump, thermostat, fan (especially if your vehicle comes factory with a clutch fan), and radiator. Factory BMW expansion tanks are plastic and prone to either breaking off at connection points or combusting. As factory rubber hoses age they either crack or break over time - we offer silicone cooling hose upgrades for most applications to avoid future failures. If you have an older vehicle, your water pump likely comes from the factory with a plastic impeller - we offer upgraded water pumps with metal impellers that are far more reliable. Newer model BMWs utilize electric water pumps - BMW spent millions of dollars engineering these water pumps, but they fail so often that we recommend replacing at 60,000 mile service intervals to avoid being stranded on the side of the road. In terms of thermostats, we offer various upgraded thermostats for racing applications. If your BMW utilizes a clutch fan from the factory, we have several options available in terms of universal electric fans - we recommend replacing these to avoid sending brittle plastic fan blades through your hood. For radiators, we recommend swapping out your radiator for one that does not use plastic connection points like your factory radiator.

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Water Pump And Thermostat Kit - BMW N52 3.0L

T#:17073598

Part#: 11537549476KT

In Stock

Sale - Save 25% $ 424.99

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

$ 318.83 USD

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Sale - Save 25%

$ 424.99

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

$ 318.83 USD

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Includes everything you may need to replace your water pump and thermostat.

Water Pump And Thermostat Kit

T#:5376274

Part#: 11517586925TKT

In Stock

Sale - Save 25% $ 448.99

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

$ 337.56 USD

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Sale - Save 25%

$ 448.99

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

$ 337.56 USD

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Everything you need to replace your water pump and thermostat. The water pumps in these BMW models are known for failure near 80,000 miles is a very common issue often times leaving the owner stranded. The aftermarket kit offered provides a single stop for water pump and thermostat replacement needs to save the search and get you back on the road. Kit includes: Mahle-Behr thermostat Water pump Genuine BMW coolant thermostat to water pump hose Mounting hardware required for both the thermostat and water pump

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Complete Cooling System Overhaul Package - 2003-4/2004 Z4 2.5 3.0 ...

T#:339100

Part#: TMS224320

In Stock at Vendor

Starting at $ 514.24 USD

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Starting at $ 514.24 USD

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This is a customizable cooling system overhaul kit, which starts off with the basic radiator and water pump and can be configured to replace all the M54 common cooling system failure parts in one package. This cooling system package is for the 2003-2005 Z4 Roadster.

The Z4 cooling system is much like that of the sister 3 series. Several of the primary cooling components are prone to failure within 60k miles (or less in many cases). A failure in the cooling system can lead to overheating and catastrophic engine failure. Don't gamble your engine! By replacing these core items preventatively, such as the radiator & waterpump, you are defusing what could be a ticking cooling system time bomb. And if you've had a failure of one of these parts, now is the time to refresh your cooling system. Available with our kit is an OEM Behr radiator, an Original BMW water pump (with updated composite impeller), thermostat (complete with housing), radiator cap, new hoses, and other essential cooling parts.

Optional items (which can be added below):

Radiator cap

Major cooling hoses

Original BMW antifreeze

Upgrade the water pump to a Stewart EMP High Performance pump

Add a new coolant expansion tank (known for cracking)

Include a new coolant level sensor (known for failing / throwing "check coolant" messages)

Include a new coolant temp sensor (located in the lower radiator hose) (re-using the old sensor and seal may lead to a leak)

Add a new thermostat for an automatic transmission (located with the expansion tank).
This cooling system overhaul kit fits the following BMWs:
2003-2005 E85 BMW Z4 2.5i Z4 3.0i

Please put a check in the boxes next to the items you wish to order.

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Thermostat Replacement Kit - E39 E46 E60 E53 Z3 Z4 With M54, M52TU En...

T#:554073

Part#: 11537509227KT3

Ships on Jan 12, 2027

$ 101.99 USD

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$ 101.99 USD

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When it comes time to replace your thermostat, be sure you have everything you need. This kit includes everything you need to replace your thermostat, including the thermostat.

Kit includes:

Mahle-Behr thermostat with gasket
Thermostat mounting hardware
1 liter of coolant

Applications:
1999-2003 E39 528i, 525i, 530i sedan, touring wagon (M52TU engine, M54 engine)
1999-2005 E46 323, 328, 325, 330 sedan, coupe, cabrio, touring wagon (M52TU engine, M54 engine)
2004-2005 E60 525i, 530i sedan, touring wagon (M54 engine)
2001-2006 E53 X5 3.0 (M54 engine)
2004-2006 E83 X3 2.5i X3 3.0i (M54 engine)
1999-2002 Z3 2.3. Z3 2.5i, 2.8 Z3 3.0i (M54 engine)
2003-2005 Z4 2.5i, Z4 3.0 (M54 engine)

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OEM Style Hose Clamps

T#:338927

Part#: HOSE-CLAMPS

In Stock

Sale - Save 3% $ 3.99

This product was last offered at the strikethrough price on
06-13-2026

Starting at $ 3.87 USD

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Sale - Save 3%

$ 3.99

This product was last offered at the strikethrough price on
06-13-2026

Starting at $ 3.87 USD

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Hose clamps for radiator hoses, coolant hoses, vacuum hoses, or intake hoses. These hose clamps are the same style as your OEM hoses with a smooth inside band to prevent cutting into the hose material.

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Water Pump and Thermostat Package - N51/N52 Engine - E82 128i, E9X 32...

T#:42873693

Part#: TMS206099GKT

In Stock

$ 729.35 USD

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Qty

$ 729.35 USD

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Our water pump/thermostat overhaul includes:

Electric Water Pump
Aluminum mounting screws for water pump
Thermostat
Connecting hose from thermostat to water pump
Hose clamps

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Complete Cooling System Overhaul Package - 4/2004-2005 Z4 2.5 3.0 ...

T#:339099

Part#: TMS16430

In Stock at Vendor

Starting at $ 514.24 USD

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Starting at $ 514.24 USD

Add to Wish List

This is a customizable cooling system overhaul kit, which starts off with the basic radiator and water pump and can be configured to replace all the M54 common cooling system failure parts in one package. This cooling system package is for the 2003-2005 Z4 Roadster.

The Z4 cooling system is much like that of the sister 3 series. Several of the primary cooling components are prone to failure within 60k miles (or less in many cases). A failure in the cooling system can lead to overheating and catastrophic engine failure. Don't gamble your engine! By replacing these core items preventatively, such as the radiator & waterpump, you are defusing what could be a ticking cooling system time bomb. And if you've had a failure of one of these parts, now is the time to refresh your cooling system. Available with our kit is an OEM Behr radiator, an Original BMW water pump (with updated composite impeller), thermostat (complete with housing), radiator cap, new hoses, and other essential cooling parts.

Optional items (which can be added below):

Radiator cap

Major cooling hoses

Original BMW antifreeze

Upgrade the water pump to a Stewart EMP High Performance pump

Add a new coolant expansion tank (known for cracking)

Include a new coolant level sensor (known for failing / throwing "check coolant" messages)

Include a new coolant temp sensor (located in the lower radiator hose) (re-using the old sensor and seal may lead to a leak)

Add a new thermostat for an automatic transmission (located with the expansion tank).
This cooling system overhaul kit fits the following BMWs:
4/2004-2005 E85 BMW Z4 2.5i Z4 3.0i

Please put a check in the boxes next to the items you wish to order.

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Water Pump & Thermostat Kit - BMW Z3 Z4 S54 3.2L

T#:48194755

Part#: ZS54WPTKT2

Ships on Dec 3, 2026

$ 1,022.99

This product was last offered at the strikethrough price on
07-16-2026

$ 968.99 USD

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$ 968.99 USD

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It is important that your coolant system is serviced at regular intervals to ensure a long life. Over time, coolant systems are exposed to high temperatures and repeated thermal cycling, which causes warping, cracking, and hardening of plastics and rubber components in the coolant system. This can lead to coolant leaks and overheating, which can result in extensive engine damage if not resolved in a timely manner. This Water Pump & Thermostat kit helps to address a few of the most problematic parts, replacing these items entirely to keep your cooling system running optimally and efficiently.

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OEM Wahler Thermostat With Housing - E46 E53 E60 E83 M54

T#:341054

Part#: 11537509227

In Stock

$ 69.99 USD

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$ 69.99 USD

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Stop leaks before they start with this new Thermostat With Housing from Wahler. Despite the fact that most BMW models are brilliant, most have common issues that can plague you during your ownership of the car. This part is one of those issues, as they are known to crack over time. This replacement part is perfect stop a crack and possibly a leak before it starts.

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OEM Wahler 80 Degree Thermostat - E46 M3, MZ3 S54, Z4 M

T#:360524

Part#: 11531318274

In Stock

$ 105.99

This product was last offered at the strikethrough price on
06-25-2026

$ 68.99 USD

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$ 68.99 USD

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Replacement 80* Celcius thermostat for E46 M3, Z3M w S54 engine, Z4M. The thermostat can be replaced on the E46 M3 without removing the water pump. This can save you money if the pump still has life left on it but the thermostat needs to be done now. Symptoms of a bad thermostat include an erratic temp gauge and a fault code. When replacing the thermostat, there are three o-rings that will likely need to be replaced between the thermostat and the water pump housing, and two on the coolant tube going to the head. We also recommend new hoses, clamps, and BMW coolant. Replacement should take about one hour.

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OEM Wahler Thermostat Assembly - E60/61 E82/88 E9X Z4 N51/N52 ...

T#:360363

Part#: 11537549476

In Stock

Sale - Save 7% $ 97.91

This product was last offered at the strikethrough price on
03-25-2026

$ 91.43 USD

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Qty

Sale - Save 7%

$ 97.91

This product was last offered at the strikethrough price on
03-25-2026

$ 91.43 USD

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If your vehicle is experiencing cooling issues, chances are the thermostat is the cause. Common symptoms include a prolonged warm-up at highway speeds from the thermostat being stuck open, or consistent overheating issues from the thermostat being stuck in the closed position. Either condition can result in poor performance and potential damage to vital components in your vehicle.

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Thermostat Replacement Kit

T#:374361

Part#: N524TSTKT1

In Stock

$ 112.99

This product was last offered at the strikethrough price on
03-26-2026

$ 111.99 USD

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$ 111.99 USD

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Wahler Thermostat O-Ring - E46, Z3, Z4

T#:362366

Part#: 11531318402

Ships in 1 Business Day

$ 6.17 USD

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Qty

$ 6.17 USD

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BMW does not include a o-ring with their new thermostats

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