CSF BMW S58 M2/M3/M4 (G87/G80/G81/G82/G83) High-Performance Auxiliary Radiator

Important - sold individually: every S58-equipped G8X requires two of these auxiliary radiators. This listing is for a single unit; if you need both sides, add a quantity of 2 to your basket.

The S58's cooling system is genuinely complex, consisting of 6 to 7 heat exchangers depending on transmission - and while the factory auxiliary radiators do a decent job in stock form, they start to show real limitations once you add power and push the car in aggressive driving conditions. With many motorsport teams and enthusiasts now pushing well over 1000 horsepower, S58 coolant temperatures can climb high enough to trigger limp mode - ruining a race, track session, or your overall driving fun.

CSF's High-Performance Auxiliary Radiator directly addresses this with a larger 2-row, 42mm core using CSF's exclusive B-Tube technology - nearly double the width of the OEM's single-row, 34mm core. Ultra-efficient 5mm tall multi-louvered fins maximise surface area contact, and 100% all-aluminium TIG-welded construction eliminates the well-documented weakness of the OEM's plastic tanks and crimp-on gaskets. A genuine practical advantage: the same part fits either the left or right side of the car, and because each side serves a different cooling system (charge air on one side, engine coolant on the other), you can upgrade just one at a time if you want to prioritise based on your build's specific needs. An integrated, bolt-on rock guard protects against road debris puncturing the core - a well-known cause of OEM coolers failing and spilling fluid mid-drive.

Works with: OEM mounting points and quick-connect fittings - suitable for both manual and ZF8 automatic transmission vehicles.

Why Choose This Auxiliary Radiator

• 2-row, 42mm core - nearly double the width of the OEM's single-row, 34mm design
• CSF's exclusive B-Tube technology - genuine increase in heat dissipation
• 100% all-aluminium TIG-welded construction - eliminates the OEM's weak plastic tanks and crimp-on gaskets
• Same part fits either side - genuine flexibility to upgrade one side at a time
• Integrated bolt-on rock guard - protects against road debris damage
• True drop-in fit - OEM mounting points and quick-connect fittings, no modification required

Compatibility

• BMW G87 M2 (2023+, S58, manual & ZF8 automatic)
• BMW G80 M3 Saloon (2021+, S58, manual & ZF8 automatic)
• BMW G81 M3 Touring (2022+, S58, manual & ZF8 automatic)
• BMW G82 M4 Coupe (2021+, S58, manual & ZF8 automatic)
• BMW G83 M4 Convertible (2021+, S58, manual & ZF8 automatic)

Sold individually - order quantity 2 for a full left and right set

Part Number

• CSF #8321, replaces OEM part #17118095285