BMW Cooling System Parts & Accessories for BMW E90 M3 S65 4.0L

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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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Goldenwrench Supply Co - Corporate Logo
T#:641289
Part#: FXXCET-R
In Stock
$ 65.00 USD
Free Shipping
$ 65.00 USD
Free Shipping
Give the plain plastic factory coolant caps an upgrade with the brand new BLACKLINE Performance Coolant Expansion Tank Cap Cover from Goldenwrench. Each cap is CNC formed from T6 Aluminum and anodized in a limited release race inspired red color. All logos and decorations are finalized through a precision 3D milling process, machined into each cap for the ultimate premium finish. The BLACKLINE Performance Billet Coolant Expansion Tank Cap Cover will fit most BMW vehicles equipped with the N55, S55, S63, and S65 engine with the large coolant tank found in the following vehicles E90/E91/E92 M3 LCI, F22 M235i, F87 M2/M2 Competition, F80 M3, F82 M4, F10/F90 M5, and more (check your coolant cap ensuring that it is the same shape as seen in the product photos). Each kit comes with a Billet Coolant Expansion Tank Cap Cover, and an Installation Instruction Card. This is a not a full cap replacement. The Billet Cap Cover affixes to the top of your factory coolant cap installing easily in minutes.
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Goldenwrench Supply Co - Corporate Logo
T#:5691129
Part#: FXXCET-B
In Stock
$ 65.00 USD
Free Shipping
$ 65.00 USD
Free Shipping
Give the plain plastic factory coolant caps an upgrade with the brand new BLACKLINE Performance Coolant Expansion Tank Cap Cover from Goldenwrench. Each cap is CNC formed from T6 Aluminum and anodized in a limited release race inspired blue color. All logos and decorations are finalized through a precision 3D milling process, machined into each cap for the ultimate premium finish. The BLACKLINE Performance Billet Coolant Expansion Tank Cap Cover will fit most BMW vehicles equipped with the N55, S55, S63, and S65 engine with the large coolant tank found in a variety of M vehicles(check your coolant cap ensuring that it is the same shape as seen in the product photos). Each kit comes with a Billet Coolant Expansion Tank Cap Cover, and an Installation Instruction Card. This is a not a full cap replacement. The Billet Cap Cover affixes to the top of your factory coolant cap installing easily in minutes.
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Goldenwrench Supply Co - Corporate Logo
T#:641288
Part#: FXXCET
In Stock
$ 65.00 USD
Free Shipping
$ 65.00 USD
Free Shipping
Give the plain plastic factory coolant caps an upgrade with the brand new BLACKLINE Performance Coolant Expansion Tank Cap Cover from Goldenwrench. Each cap is CNC formed from T6 Aluminum and anodized with an Anthracite Gray color to compliment the factory engine cover. All logos and decorations are finalized through a precision 3D milling process, machined into each cap for the ultimate premium finish. The BLACKLINE Performance Billet Coolant Expansion Tank Cap Cover will fit most BMW vehicles equipped with the N55, S55, S63, and S65 engine with the large coolant tank found in the following vehicles E90/E91/E92 M3 LCI, F22 M235i, F87 M2/M2 Competition, F80 M3, F82 M4, F10/F90 M5, and more (check your coolant cap ensuring that it is the same shape as seen in the product photos). Each kit comes with a Billet Coolant Expansion Tank Cap Cover, and an Installation Instruction Card. This is a not a full cap replacement. The Billet Cap Cover affixes to the top of your factory coolant cap installing easily in minutes.
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ECS Exact-Fit Silicone Radiator Hoses - E9X M3 S65
10X Entries Into Our F80 M3 Sweepstakes
ECS - Corporate Logo
T#:39531769
Part#: 008645LA02
In Stock
Sale - Save 3% $ 177.99

This product was last offered at the strikethrough price on
06-14-2026

$ 172.65 USD
Free Shipping
Sale - Save 3%
$ 177.99

This product was last offered at the strikethrough price on
06-14-2026

$ 172.65 USD
Free Shipping

Tired of dealing with brittle, dry-rotted rubber hoses? Whether you're refreshing your cooling system or replacing aging components, this ECS Silicone Radiator Coolant Hose Set is the ultimate upgrade. Designed for durability, performance, and a factory-perfect fit, these premium silicone hoses outperform standard rubber in every way.

Why Choose Silicone Over Rubber?

Made from heavy-duty, reinforced 4-ply fluorosilicone, ECS hoses withstand extreme temperatures and pressures far beyond OEM rubber hoses. Engineered to resist oil, fuel, and electrochemical degradation, these hoses are tested for continuous operation at 250°F and over 45 psi, delivering superior reliability, reduced turbulence, and improved coolant flow.

Key Benefits:

Direct OE Fitment – Perfectly molded to factory specifications for seamless installation on your S65-equipped E9X M3. Enhanced Durability – Heat-resistant silicone prevents cracking, swelling, and deterioration over time. Superior Cooling Performance – Smoother internal passageways improve coolant flow and system efficiency. Pre-installed Quick-Connect Fittings – Hassle-free installation with OEM-style connectors. Premium Hardware Included – Comes with German-style stainless steel worm-drive hose clamps for a secure fit. Kit Includes:

Upper Radiator Hose Lower Radiator Hose Pre-Installed Factory "Quick-Connect" Flanges (4) Stainless Steel Worm-Drive Hose Clamps (4) Replaces OEM Part Numbers: 11537838214 & 11537840661.

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Genuine BMW Motorsport - Corporate Logo
T#:5574
Part#: 11518331044
Special Order: No Guaranteed ETA
$ 999.99 USD
Free Shipping
$ 999.99 USD
Free Shipping
Upgrade from the plastic impeller on the stock water pump to this aluminum impeller pump originally developed by BMW for the M3 GT4. This aluminum water pump was designed to stand up to the abuse of racing but can be used on a standard street car.
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