Just like the rest of your vehicle's major systems, the cooling system must also be addressed periodically to ensure proper cooling and component reliability. Plastic and rubber components become brittle and prone to splitting or cracking after long periods of heating and cooling cycles, especially in colder climates! The coolant itself can degrade or become contaminated, leading to potential corrosion or freezing issues. Finally, thermostats and sensors can fail completely, preventing proper cooling and/or coolant temperature readings to become inaccurate.

To make sure you are not left stranded on the side of the road with an overheated engine, we have put together this Basic Cooling System Service kit. This kit contains all of the most-likely-to-fail components, giving you peace of mind knowing your engine will continue to run cool for another 60,000+ miles.

See kit contents below for all included components.

BMWs are well-known for their problematic cooling systems, which are often a catalyst for irreversible engine damage and a hefty repair bill. The coolant expansion tank—a crucial component responsible for holding hot engine coolant under high pressure—is a common cause of cooling system issues. Unfortunately, BMW chose to manufacture the factory E9X N55 expansion tank out of plastic. After years of exposure to high coolant temperatures, ambient engine bay heat, and chemical-rich antifreeze, the plastic degrades, eventually weakening enough to fail catastrophically.

With this issue in mind, our team of BMW enthusiasts engineered the ultimate cooling system upgrade for E82/88 and E90/92/93 owners: a heavy-duty expansion tank built to last! Crafted from durable 5052 TIG-welded aluminum, this tank resists high temperatures and pressures without degrading over time. Unlike the fragile OEM plastic tank, Turner’s design eliminates the risk of cracking, leaking, or failure. Upgrade to our Heavy Duty Aluminum Expansion Tank Kit and say goodbye to expansion tank issues for good!

To guarantee exact fitment, the upgraded tank was designed using advanced 3D CAD modeling. All bungs, nipples, and fittings are precision-machined to ensure a secure seal with factory hose ends. Unlike other aftermarket options, this tank maintains the factory coolant capacity and includes our laser-cut logo plate at the top, providing an accurate fill level. Internal baffles are incorporated to prevent fluid cavitation, eliminating air pockets in the cooling system and avoiding false coolant level warnings during spirited driving.

Engineered for high-performance builds and daily drivers alike, this expansion tank boasts a premium wrinkle black powder coat finish for a clean "OEM+" aesthetic. This tough coating not only enhances appearance but also protects against corrosion for long-term durability. The kit includes a silicone overflow hose, a high-quality level sensor, and an OE expansion tank cap, offering a complete cooling system upgrade. Avoid the risks of the factory expansion tank—upgrade your N55-equipped BMW today and drive with confidence!

Features & Benefits:

Durable 5052 TIG-Welded Aluminum Construction: Ensures long-term reliability and eliminates expansion tank failure. Premium Wrinkle Black Powder Coat Finish: Offers an "OEM+" appearance while preventing corrosion. Factory Coolant Capacity Retention: Maintains the same coolant level as the original design. Laser-Cut Turner Logo Plate: Provides a clear and accurate fill level indicator. Internal Baffles: Prevent the introduction of air pockets during high-performance driving. Precision-Machined External Bungs and Fittings: Ensure a perfect fit for factory hose connections. Kit Includes:

Turner Motorsport Aluminum Expansion Tank Performance Silicone Coolant Overflow Hose Aluminum Coolant Bleeder Screw Ball Stud 6mm Fitting Expansion Tank Cap Coolant Level Sensor Product Development:

Our Heavy Duty Aluminum Expansion Tank was designed, engineered, tested, and quality inspected by our Research & Development team. Our development process includes leading-edge product technology: FARO laser scanning for reverse engineering and quality inspection, SolidWorks 3D CAD modeling, rapid prototyping utilizing our in-house 3D printer, and rigorous long-term product testing.

Installation:

To aid in the installation process, we've assembled a start-to-finish installation guide, including detailed instructions on removing your factory cooling expansion tank and associated components.

Click HERE for Installation Instructions

Upgrading your cooling system or replacing old, brittle rubber hoses? Don't just replace them—upgrade them. This silicone coolant outlet hose from ECS Tuning delivers perfect OEM fitment with superior heat tolerance and a longer service life. Unlike standard rubber, which softens and degrades from constant heat cycles, high-grade silicone is built to last. Give your cooling system the reliability it deserves.

This hose connects the outlet on the thermostat housing to the front of the cylinder head. It replaces OEM BMW part number 11537584549.

Track-tested and street-ready. the ULTIMATE cooling system upgrade for your N54 or N55!

Ditch your failure-prone plastic end tanks and increase cooling capacity by 25%, all without modifying your core support or accompanying shrouds. The CSFxTurner Performance Triple-Pass Radiator is the best cooling system upgrade for your N54/N55-equipped BMW!

The BMW 135i and 335i deliver serious performance straight from the factory, thanks to the twin-turbocharged N54 and single-turbo N55 engines. With strong midrange torque, high-revving capabilities, and proven tuning potential, these engines punch well above their weight. However, while the powertrain excels, the factory cooling system often falls short, especially under sustained boost or track conditions. Heat soak, rising coolant temps, and long-term thermal stress are common issues for enthusiasts pushing their N54 or N55 hard, making a performance radiator an essential upgrade for reliability and consistency.

Recognizing the critical need for increased cooling capacity, the team at Turner Motorsport partnered with CSF Race, world leaders in high-performance cooling systems with over 50 years of experience. The result is an Upgraded Performance Radiator: a high-performance, motorsport-grade upgrade engineered to keep your N54/N55 cooler and on the track for longer.

Design:

CSF-Exclusive "B-Tube" Technology
Unlike conventional "O-tube" designs, CSF’s patented "B-tube" structure increases wall strength while creating a more efficient flow path. This alone accounts for a 15% increase in cooling capacity over an OE "O-tube" radiator!
Dual Core Design
2-Row 42mm Core (Dual Core) Featuring CSF's Exclusive B-Tube Technology
Two-Row Compact Structure
This radiator was designed with precise fitment in mind. While total tube count and size are increased, the overall radiator dimensions stay the same as OE, ensuring a drop-in fit with zero modifications required.
25% Increase in Cooling Capacity
All of the above design features translate to a massive 25% cooling increase over the stock radiator!
FEATURES & BENEFITS

Direct-fit upgrade, no modifications required!
Accepts all OEM attachments via CNC-machined "Quick-Connect" hose ends and accessory mounting provisions
TIG-welded aluminum construction provides increased durability
An all-aluminum drain plug replaces the weak OE plastic unit, ensuring seamless functionality for the life of the radiator
Increased cooling efficiency for high-performance and racing use
Aluminum drain plug
Designed and tested by Turner Motorsport in collaboration with CSF Race
Backed by the Turner Lifetime Replacement Program
Every unit features precision CNC-machined brackets and OE-style connections for a seamless, drop-in installation using factory or aftermarket hoses. Whether you're building a track weapon or a high-horsepower street car, this Turner x CSF radiator is the cooling solution your N54 or N55 needs to perform reliably under pressure. All backed by the Turner Lifetime Replacement Program.

This packages covers the major components you would install along with a new water pump or thermostat. On the N54 cars (135i, 335i, 535i) the water pump and theremostat are mounted together. In fact, to get to the thermostat, BMW expects you to remove the water pump. This package covers the whole job. With the electric water pump now an integral part of the efficiency and performance of the engine, staying on top of its maintenance and replacement is the smart thing to do.

Our water pump/thermostat overhaul includes:

• OEM VDO electric water pump, p/n 11517588885 or 11517632426
• OEM mounting screws for water pump (set of 3), p/n 11517602123
• OEM Behr thermostat, p/n 11537549476
• Original BMW connecting hose from thermostat to water pump, p/n 11537545665
• Original BMW hose clamps for hose (x 2)
  
• BUY AS A PACKAGE AND SAVE $$!
  
  The water pump on the N54 engine has more cooling responsibilities than ever before. Not only must it provide cooling for the engine, but it's also pumping fluid used to cool the turbocharger oil and automatic transmission oil. The good news is that the pump only works when, and only as much, as it needs to. The engine computer dictates how much fluid needs to be pumped through the system depending on the load. That means the system can actually stop the pump when warmer temperatures are needed. No longer is the pump spinning all the time from an engine-driven belt. The bad news is that it's now an electrical part, so a failure is usually immediate and with no warning. And if the electronics are at fault, there is no way to rebuild or repair it. Fortunately, the engine computer will force a shut down or reduce power if a problem occurs, preventing catastrophic engine damage.
  
  How to avoid a water pump failure in the future? Replacing the water pump as part of a regular interval schedule will ensure you always have a functioning pump in place. Since this technology is relatively new for BMW, therefore the lifecycle of the pump isn't yet known, we have been recommending replacement every 80-100k miles. This package of OE/OEM parts covers everything with Original BMW coolant offered to finish off the job. A proper bleeding procedure must be followed with the new electric pump.
  
  This water pump package fits the following BMWs with the N54 engine:
  2007-2010 E60 BMW 535i 535xi 535i xDrive
  2008-2010 E82 BMW 135i
  2011-2012 E82 BMW 1M Coupe
  2006-2010 E90 BMW 335i 335xi 335i xDrive - Sedan
  2007-2010 E92 BMW 335i 335is 335xi 335i xDrive - Coupe
  2007-2010 E93 BMW 335i - Convertible

Schwaben Locking Hose Pinch-Off Pliers have adequate clamping force to effectively seal large or pressurized cooling system hoses. These pliers are ideal for clamping shut most hoses, ensuring reliability in your automotive tasks. With swivel jaws, they provide even clamping force, making them a versatile tool for various applications.

• Adequate clamping force for large or pressurized hoses
• Ideal for clamping shut most hoses
• Swivel jaws ensure even clamping force
• Versatile tool for automotive maintenance

WARNING: This product contains chemicals known to the state of California to cause cancer, birth defects, and/or reproductive harm. For more information, visit http://www.p65warnings.ca.gov.

CSF is one of the premier cooling product specialists available on the market thanks to designs such as their High Performance Aluminum Radiators. Using a single pass designed core, this radiator gives you all the cooling you could ever need. Paired with these radiators are CNC machined brackets and corrosion resistant hardware that allow final installation to have a same as stock fitment! This enables you to have much higher cooling without having to cut away any metal or delete any important components just for the sake of lower coolant temperatures. 

Features:

• Two-row, triple-pass design radiator core
• CNC machined mounting brackets
• All needed hardware included
• Hand polished aluminum with a mirror-like finish
• Stock fitment prevents modification to engine bay

Fits the following BMWs:
2006-2012 E9X BMW 325i 328i 330i

If you plan to drive your BMW aggressively on the track, it is important that you upgrade your cooling system to avoid overheating. To ensure your BMW keeps cool on the track, we have built out our new High Performance Cooling System Upgrade kits. Featured in this kit is everything you will need to redo your cooling system from top to bottom with OEM components, with select stock components swapped out for the high performance alternative! This kit includes a high performance CSF Aluminum Radiator for significantly better cooling than the stock radiator and full aluminum construction that won't crack from long term heat cycling, and a Mishimoto Performance 74*C thermostat for lower temperature operation and increased cooling of the engine. 

Additional items included in this kit:

• OEM Replacement Coolant Hoses
• ECS Tuning Silicone Coolant Outlet Hose with ECS Billet Thermostat Hose Adapter
• ECS Tuning Aluminized Water Pump Hose
• OEM Expansion Tank, Cap, and Level Sensor
• OEM Belts, Tensioners, and Pulleys
• OEM Auxiliary Fan Switch
• OEM VDO Water Pump
• Genuine BMW Hardware for Easy Installation
• Genuine BMW Antifreeze/Coolant (Undiluted) - 2 Gallons

This is a compete cooling system overhaul kit, which includes all the common cooling system failure parts bundled into a complete package. This cooling system package is for the E82/88 135i or E90/92/93 335i/xi/is with the N54 engine. 

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 thermostat housing, radiator, and 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 entire cooling system. Keep on top of the cooling needs of your engine for your own piece of mind. Potential buyers also see the upside of a properly maintained car with receipts. 

For vehicles with manual transmission only

This is a compete cooling system overhaul kit, which includes all the common cooling system failure parts bundled into a complete package. This cooling system package is for the E82/88 135i or E90/92/93 335i/xi/is with the N54 engine. 

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 thermostat housing, radiator, and 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 entire cooling system. Keep on top of the cooling needs of your engine for your own piece of mind. Potential buyers also see the upside of a properly maintained car with receipts. 

For vehicles with automatic or DCT transmission only

If you plan to drive your BMW aggressively on the track, it is important that you upgrade your cooling system to avoid overheating. To ensure your BMW keeps cool on the track, we have built out our new High Performance Cooling System Upgrade kits. Featured in this kit is everything you will need to redo your cooling system from top to bottom with OEM components, with select stock components swapped out for the high performance alternative! This kit includes a high performance CSF Aluminum Radiator for significantly better cooling than the stock radiator and full aluminum construction that won't crack from long term heat cycling, and a Mishimoto Performance 74*C thermostat for lower temperature operation and increased cooling of the engine. 

Additional items included in this kit:

• OEM Replacement Coolant Hoses
• ECS Tuning Silicone Coolant Outlet Hose with ECS Billet Thermostat Hose Adapter
• ECS Tuning Aluminized Water Pump Hose
• OEM Expansion Tank, Cap, and Level Sensor
• OEM Belts, Tensioners, and Pulleys
• OEM Auxiliary Fan Switch
• OEM VDO Water Pump
• Genuine BMW Hardware for Easy Installation
• Genuine BMW Antifreeze/Coolant (Undiluted) - 2 Gallons

Just like the rest of your vehicle's major systems, the cooling system must also be addressed periodically to ensure proper cooling and component reliability. Plastic and rubber components become brittle and prone to splitting or cracking after long periods of heating and cooling cycles, especially in colder climates! The coolant itself can degrade or become contaminated, leading to potential corrosion or freezing issues. Finally, thermostats and sensors can fail completely, preventing proper cooling and/or coolant temperature readings to become inaccurate.

To make sure you are not left stranded on the side of the road with an overheated engine, we have put together this Basic Cooling System Service kit. This kit contains all of the most-likely-to-fail components, giving you peace of mind knowing your engine will continue to run cool for another 60,000+ miles.

See kit contents below for all included components.