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BMW Cooling System Parts & Accessories for BMW 3 Series E46 (1999-2005)

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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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Bav Auto Thermostat With Aluminum Housing - M52TU M54

T#:12544802

Part#: 11531437040

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$ 84.99 USD

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The plastic thermostat cover in your BMW is a known point of failure. Throughout years of repeated contact with hot coolant, the plastic can crack and cause massive coolant leaks and potential overheating. Eliminate one of the weak links in your cooling system with a replacement aluminum thermostat housing. By installing this aluminum unit, you have no worries as far as plastic housing cracks go

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Engine Fan - 11 Blades, 420mm - Many 6 Cylinders

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T#:1287

Part#: 11521712058

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$ 32.19 USD

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This fan is driven by the serpentine belt, engaged by the fan clutch. If you have bad motor mounts, it's quite common for the blades of this fan to make contact with the radiator or radiator shroud, essentially self-destructing the fan into many peices. Be sure to get a new fan clutch, while you are replacing this.
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 fan fits many 6 cylinder BMWs, including the following:

1989-1994 E32 735i/iL
1991-1995 E34 525i, 535i, M5
1992-1999 E36 3 series with 6 cylinder engine (M3, 325, 328, 323)
1997-2002 Z3 2.3, 2.5, 2.8, 3.0, and MZ3 3.2 (S52)
1997-2003 E39 5 series, 525i, 528i, 530i
1999-2000 E46 3 series 323i/Ci, 328i/Ci
2001-2005 E46 3 series WITH AUTOMATIC TRANSMISSION ONLY
2001-2006 E46 M3 (all):
2001-2006 X5 3.0i

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URO Radiator Fan Clutch

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T#:362006

Part#: 11527505302

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$ 72.99 USD

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Common source of engine overheating

Bav Auto Coolant Expansion Tank - E53 X5, E46, E83 X3

T#:640496

Part#: 17137787039

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$ 50.99 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. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Manual Trans ...

For vehicles with a manual transmission only

T#:638088

Part#: 17111436250

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$ 35.99 USD

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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on an E46 3 series with a Manual Transmission. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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Bav Auto Heater Inlet Pipe - E46 E39 E53 E83 E85 Z3

T#:638080

Part#: 11531705210

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$ 32.79 USD

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This is the plastic heater inlet pipe that connects the cylinder head to the heater inlet on cars with the M52 or M54 engine. The plastic on this hose becomes brittle over time and eventually leads to failure. Replace yours with a brand new Bav Auto Heater inlet pipe to prevent catastrophic failure.

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Bavarian Autosport Water Pipe - E46 E39 Z4 Z3 (M52TU, M54)

T#:638085

Part#: 11537502525

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$ 40.79 USD

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This plastic water pipe is positioned directly underneath your intake manifold. Due to its plastic construction, it is notorious for catastrophic failure. Rapid cooling loss and overheating are both direct results of this failure, posing permanent and lasting damage to the engine.

Replace your cracked/broken coolant pipe with this high-quality Bavarian Autosport component to ensure long-term reliability and perfect fitment.

From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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Radiator Fan Clutch

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T#:373088

Part#: 11527831619

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$ 71.83 USD

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Direct replacement

Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans ...

For vehicles with an automatic transmission only

T#:638089

Part#: 17111436251

In Stock

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$ 36.79 USD

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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on E46 3 series and E85/E86 Z4 with an Automatic Transmission. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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BMW E46 Cooling Fan Shroud

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T#:377316

Part#: 17111436259

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$ 52.89 USD

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BMW E46 Cooling Fan Shroud is essential for maximizing airflow through your radiator, ensuring optimal engine cooling. This shroud is designed to create the most efficient pull of air, keeping your engine temperature under control, especially during demanding driving conditions.

Enhanced Cooling Efficiency: Maximizes airflow through the radiator, ensuring your engine stays cool.
High-Quality Construction: Manufactured by URO Parts, a leading brand known for producing reliable and durable replacement components.
Precision Fit: Designed specifically for the BMW E46, ensuring a perfect fit and easy installation.
ISO 9000 Certified: Built to meet ISO 9000 certification standards for long-lasting performance and reliability.
Trusted by Enthusiasts: URO Parts is a trusted name in the automotive industry, offering components that deliver OEM-like performance.

Upgrade your BMW E46 with this Cooling Fan Shroud from Turner Motorsport to enhance your vehicle’s cooling system and maintain peak performance.

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BMW E46 M3 S54 3.2L Water Pump

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T#:378573

Part#: 11517838159

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$ 105.79 USD

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Includes sealing gaskets

BMW Water Pump - Remanufactured - 11517527799

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T#:372932

Part#: 11517527799

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$ 42.99 USD

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$ 42.99 USD

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Features a metal impeller for reliability

URO Auxiliary Cooling Fan Assembly

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T#:377306

Part#: 17117561757

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$ 217.99 USD

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$ 217.99 USD

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The auxiliary fan in your vehicle serves an extremely important role. When your car reaches temperatures that may be hazardous to your engine, the auxiliary fan moves air through the radiator to provide better cooling. Usually activated during times of stationary vehicle operation, it supplements the air usually driven through the radiator by driving down the road. If your vehicle is getting too hot during traffic or at stop lights, your auxiliary fans are probably faulty. Replace yours with this piece from ACM to restore the factory cooling in your vehicle and prevent catastrophic damage to your engine. Even if your fans are still operational but the blades are damaged or cracked, replacement is the only solution.

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URO - Heater Inlet Pipe - E46, Z3, E39

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T#:34080697

Part#: 11531705210

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$ 34.49 USD

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This runs from the front left side of the cylinder head under the intake manifold toward the firewall.

URO Coolant Expansion Tank - BMW E46 M3

T#:48608189

Part#: 17112283344

Ships in 1 Business Day

$ 155.99 USD

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$ 155.99 USD

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This radiator coolant reservoir/expansion tank for E46 M3 is a common failure item as the plastic weakens and cracks, causing coolant leaks. If your E46 M3 has over 80k miles and still has the original expansion tank, we highly recommend replacing it during your next major service.

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Coolant Expansion Tank - E53 E46 E83 M52 M54

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T#:373103

Part#: 17137787039

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$ 45.99 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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URO Expansion Tank Hose - Heater Core To Expansion Tank - BMW E46 M52...

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T#:43750239

Part#: 64218376153

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$ 29.99 USD

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$ 29.99 USD

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Over the years and with exposure to extremely hot coolant, the coolant hoses in your vehicle can take a beating. Being made of reinforced rubber, these hoses can fail in a number of ways. Splitting at a hose clamp, swelling, cracking, and breaking are just a few of the ways this hose can leave you stranded. Replace it at the first sign of wear to keep your coolant in your engine. With the proper diameter, bends, and lengths, this is the perfect replacement for any swelled or damaged hose. An easy installation, it's piece of mind the next time you are on a long trip or your morning commute.

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URO Auxiliary Pusher Fan Assembly - With Frame - E46

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T#:592701

Part#: 64546988913

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$ 202.99 USD

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The auxiliary fan in your vehicle serves an extremely important role. When your car reaches temperatures that may be hazardous to your engine, the auxiliary fan moves air through the radiator to provide better cooling. Usually activated during times of stationary vehicle operation, it supplements the air usually driven through the radiator by driving down the road. If your vehicle is getting too hot during traffic or at stop lights, your auxiliary fans are probably faulty. Replace yours with this piece to restore the factory cooling in your vehicle and prevent catastrophic damage to your engine. Even if your fans are still operational but the blades are damaged or cracked, replacement is the only solution.

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Expansion Tank Retaining Plate

For vehicles with automatic transmission only

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T#:362912

Part#: 17111436251

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$ 53.99 USD

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

URO Water Distribution Pipe - E46

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T#:578992

Part#: 17111707817U

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$ 27.99

This product was last offered at the strikethrough price on
04-15-2026

$ 22.99 USD

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Plastic 3-way flange that brings together lower radiator hose-expansion hose-bypass hose.

Expansion Tank Mounting Plate

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T#:584756

Part#: 17111436250

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$ 49.99 USD

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Replace your broken mounting plate to keep your expansion tank secure and prevent leaks.

URO Parts Thermostat Assembly - 11537509227

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T#:29466801

Part#: 11537509227

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$ 41.99 USD

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The thermostat cover in your BMW, made from plastic, is notorious for failing. After years of exposure to hot coolant, the plastic can crack, leading to significant coolant leaks and potential engine overheating.

URO Parts offers a superior solution with their high-quality thermostat cover, designed to surpass the durability of the original factory part. This replacement thermostat comes complete with a gasket for an effortless service.

Features:

Perfect Fit: Guaranteed fitment ensures a seamless replacement process. Optimal Cooling: High-flow OE-style design ensures efficient engine cooling performance. Easy Installation: Manufactured to factory housing dimensions for straightforward bolt-on installation and secure hose connections. Comprehensive Design: Includes ports for temperature sensors where applicable. Superior Materials: Constructed from high-quality alloy or composite materials that resist temperature-induced warping or cracking, preventing coolant leaks. URO Parts, with over 8,000 premium spare parts, specializes in manufacturing precise, durable replacements for factory BMW components. Committed to the highest standards of precision, materials, and workmanship, each part is rigorously tested to deliver the best combination of durability, functionality, and affordability. For reliable replacement parts that offer great value, choose URO Parts.

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Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 ...

T#:640208

Part#: 17117639022

In Stock

Sale - Save 15% $ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 USD

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This radiator expansion tank cap is used most BMW's from 1991-2006. 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. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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Temperature Sensor

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T#:37892090

Part#: 13621433076

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$ 10.34 USD

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$ 10.34 USD

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Temperature sensor for monitoring coolant and oil

Radiator Drain Plug

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T#:380524

Part#: 17111437361

In Stock

$ 3.99 USD

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$ 3.99 USD

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Usually stripped out after being removed

Water Connection Pipe

T#:15511839

Part#: 17111707817

In Stock

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05-03-2026

$ 15.19 USD

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Connects the radiator to the expansion tank

Auxiliary Fan Switch O-Ring

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T#:377077

Part#: 13621433077S

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$ 0.88 USD

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$ 0.88 USD

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Now you can just replace the o-ring instead of the whole switch

Radiator Drain Plug (Adjustment Screw) - Priced Each

For vehicles with manual transmission only

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T#:593031

Part#: 17111437359

Ships in 1 Business Day

$ 8.99 USD

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$ 8.99 USD

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This is the drain plug (adjustment screw) for manual transmission equipped cars.

URO Thermostat Housing Gasket - BMW M52TU M54

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T#:639269

Part#: 11537509357

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$ 2.99 USD

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$ 2.99 USD

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Prevent leaks with a brand new thermostat housing gasket from URO

Expansion Tank Mounting Clamp

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T#:591954

Part#: 17111707777

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$ 6.99 USD

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Locks the expansion tank into the mounting plate via the large hole in the bottom of the tank

Water Pump O-Ring

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T#:555320

Part#: 11537830709

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$ 2.99 USD

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$ 2.99 USD

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When it comes time to replace the water pump, be sure to replace all the O-Rings associated with it to ensure that your car stays leak free. If you are experiencing leaking issues, be sure to inspect these rings, as they might have worn down. This is used on the return pipe to the thermostat housing

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Bav Auto Temperature Sensor - BMW E39 E46 E9X E60 F01/02

T#:639833

Part#: 13621433076

In Stock

Sale - Save 20% $ 14.99

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$ 11.99 USD

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This is the coolant temperature sensor used in many BMW models from the late-1990s to the mid-2010s. The engine computer relies on the coolant temp to set the fuel mapping for the engine. As the car warms up the computer changes the fuel mixture. If your car is running a bit rich (too much fuel) it could be because this sensor is failing and not sending the correct info to the computer. This sensor is located in a variety of places depending on the engine. But it's one of those easy replacement items 'while you're in there' when doing a water pump or thermostat replacement. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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URO Radiator Mounting Bracket - E46 Z4

Right Lower Left Lower

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T#:593030

Part#: 17111436264

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$ 9.99 USD

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$ 9.99 USD

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URO Parts is one of the leading manufacturers of high quality direct replacement aftermarket components, covering a wide range of makes and models. All of their replacement parts are manufactured to ISO 9000 certification standards, so you can expect long lasting performance from URO Parts.

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Auxiliary Fan Switch

Mounted in upper radiator hose, controls operation of auxiliary fan Mounted in lower radiator hose, controls operation of auxiliary fan

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T#:376847

Part#: 13621433077

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$ 10.99 USD

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Comes with related o-ring

Radiator Drain Plug With Housing

For vehicles with automatic transmission only

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T#:593032

Part#: 17111437360

In Stock

$ 10.99 USD

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This is the drain plug (adjustment screw) for automatic transmission equipped cars.

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