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This product was last offered at the strikethrough price on
06-14-2026
Our Turner Motorsport's full aluminum expansion tank was designed and engineered in house to help with the weak point in your E46 cooling system. The coolant expansion tank goes through heat cycles over and over again from regular driving, it is important that your expansion tank is doing its job to retain coolant to keep your engine operating temperatures down and keep your engine bay clean. Not only is this a major upgrade but also a great maintenance item to replace. Our expansion tank was designed to fit the OEM hoses for an easy install and comes with all the upgraded items you will need for a clean install.
If your BMW needs a new expansion tank, make sure this is the last expansion tank you ever need to buy. Our coolant expansion tank has a full aluminum construction and wrinkle black powder coat for durability. Expansion tank kit comes with all the accessories you need to replace your expansion tank once, and never have to worry about it again.
Product Features:
Maintains stock coolant capacity and expansion volume
Designed to maintain OE coolant elevation, preventing air pockets
Baffled tank ensures that air pockets cannot be introduced during aggressive driving and provides accurate coolant level reading
Carefully designed bleed passage prevents the introduction of air as the engine cools
Turner engraved internal fill level
TIG welded 5052 aluminum construction
All bungs are machined to fit factory hose ends
Kit contents:
Turner Aluminum Expansion Tank
Coolant level sensor
Expansion tank cap
Flared coolant pressure release line
Hardware for installation
Product Development:
Turner expansion tanks are designed, engineered, tested and quality inspected by our Research and Development team at Turner. Nothing but the highest level of precision and quality through leading-edge product development technology including 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.
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
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 E46 M3 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 E46 M3 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 E46 M3 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 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.
Ditch your failure-prone plastic end tanks and increase cooling capacity by 25%—all without modifying your core support or accompanying shrouds. This Performance Triple-Pass Radiator is the ULTIMATE cooling system upgrade for your S54-equipped BMW!
The E46 M3 is a masterclass in German engineering. Harboring six independent throttle bodies, infinitely variable dual-VANOS, and an 8,000 RPM redline, the S54 is practically a racing engine for the road. Unfortunately, the engine's motorsport pedigree didn't quite make it to the cooling system. The OEM radiator, while superior to its non-M counterpart, struggles to keep coolant temperature in check under sustained high-RPM conditions. Heat soak, elevated operating temperatures, and component fatigue are all too familiar to M3 owners who track their S54 regularly.
To solve this problem, we teamed up with CSF Race, a global leader in high-performance cooling solutions with over five decades of industry experience. Together, we developed the CSFxTurner Triple-Pass Radiator: a high-performance, no-compromise solution built to meet the cooling demands of track-day warriors.
Part 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! Triple-Pass Core Design As the name suggests, this unique structure forces coolant through the core three times before exit, resulting in a substantial temperature delta across the radiator core. 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 & Performance 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 Designed and tested by Turner Motorsport in collaboration with CSF Race
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
Replace the Achilles heel of your factory cooling system with a stout and reliable mechanical thermostat setup.
The factory E46 thermostat housing is a combined unit featuring a plastic housing and a built in thermostat that you cannot replace separately. These plastic all-in-one units are commonly know to crack or fail causing a headache, a trip on the tow truck and possible damage to your engine.
Taking cues from the reliable M50 thermostat setup we designed a an assembly that not only converts your plastic housing into a billet aluminum unit but also swaps out the integrated thermostat for a separate replaceable thermostat. The ability to swap out thermostats separately from the whole housing opens up doors to changing thermostats to different temperature ratings based on your application while also providing lower maintenance costs. No longer do you have to replace the whole housing but just the thermostat itself.
The billet housing is designed to be utilized with E46 M3 upper and lower radiator hoses and also features -16 ORB connections for custom radiator hoses. A major upgrade from the factory and aftermarket plastic units. Our thermostat housing kit can be used by the savvy daily driver or the track hero who wants to ensure the durability of their cooling system.
Key benefits:
Uses M50/S50 mechanical thermostat for increased reliability
Option to use aftermarket colder thermostats if desired
Thermostat can be replaced separately for lower maintenance cost
Barbed hose connections for use with E46 M3 hoses or built in -16 ORB connections for custom radiator hoses
Design:
Machined out of a single piece of billet 6061 aluminum, this thermostat housing will withstand higher prolonged temperatures and abuse for performance applications
Black anodized with engraved Turner logo on the front to match the Turner Motorsports Power Steering Reservoir
Viton gasket for superior sealing performance
For use with E46 M3 radiator hoses 11537830715 and 11537830716
Kit contents:
6061 Billet Aluminum Thermostat Housing
Mechanical Thermostat
Thermostat Housing Gasket
Thermostat Harness
Optional Silicone or Rubber E46 M3 coolant hoses
Product Development:
Our Billet Thermostat Housing upgrade was designed, engineered, tested and quality inspected by our Research and Development team at Turner. Nothing but the highest level of precision and quality through leading-edge product development technology including 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.
This product was last offered at the strikethrough price on
06-13-2026
This product was last offered at the strikethrough price on
06-13-2026
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.
Other items to consider replacing at the same time are the radiator cap, coolant level sensor, lower radiator hose, coolant temp sensor, 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.
As a leading source of high-performance BMW parts and accessories since 1993, we at Turner Motorsport are honored to be the go-to supplier for tens of thousands of enthusiasts the world over. With over two decades of parts, service, and racing experience under our belt, we provide only quality performance and replacement parts. All of our performance parts are those we would (and do!) install and run on our own cars, as well as replacement parts that are Genuine BMW or from OEM manufacturers. We only offer parts we know you can trust to perform!
Ensure the optimal performance of your BMW by addressing the crucial component of the water pump. Turner Motorsport provides high-quality water pumps designed to keep coolant flowing smoothly. If left unchecked, a failing water pump can lead to overheating issues, potentially causing damage to engine internals. Common among German vehicles, water pump failure may result in unnecessary visits to the repair shop. Preventive maintenance, especially during timing belt replacements, is essential to avoid rapid coolant temperature rise and potential engine damage.
This product was last offered at the strikethrough price on
05-15-2026
This product was last offered at the strikethrough price on
05-15-2026
