When you start leaning on the S55, the factory cooling system works hard. A few back to back pulls, a hot track day, or a tuned setup pushing more boost and you can feel temps creeping up. The CSF Auxiliary Radiator brings confidence back into the drive. Longer sessions. Harder pulls. No early cooldown laps. Just consistent power every time you roll into the throttle on your BMW F80 M3, BMW F82 M4, or BMW F87 M2 Competition.

CSF developed this unit after seeing the limits of the aging factory coolers. Years of heat cycles, bent fins, and clogged passages reduce efficiency fast. Through real world track testing and performance data analysis, CSF redesigned the auxiliary radiator from the ground up. The result is greater thermal capacity, improved airflow efficiency, and stronger mounting integrity. It is built to handle aggressive street driving and serious circuit abuse without flinching.

Precision Engineered Design

This unit features a 2 row 42mm high efficiency core, compared to the OEM 1 row 41mm design. Core size is increased by approximately 7 percent, while tank volume is increased by roughly 10 percent thanks to the integrated modular mounting design.

CSF Exclusive B Tube Technology increases tube strength and maximizes heat transfer efficiency. The core uses ultra efficient 6.5mm tall multi louvered fins for increased surface area contact and airflow optimization.

Construction is 100 percent all aluminum with full TIG welded assembly for durability and leak resistance. Stronger metal mounting pins and brackets replace the fragile factory plastic mounting pod. Each unit is individually leak and pressure tested before leaving production. A satin black finish adds corrosion resistance and keeps things looking clean behind the grille.

Integrated bolt on rock guards help protect against road debris, a common failure point for factory coolers.

Configuration Options

Sold individually. All applications require two auxiliary radiators.

Multi fit modular design allows installation on either left or right side. Fittings and plugs are swappable for flexible installation.

Right side radiator supports the charge air cooling system.
Left side radiator supports the engine cooling system.

You can replace one side at a time depending on your cooling goals.

Exhaust Tips & Customization

Not applicable. This product is a direct fit cooling upgrade with OEM style quick connect inlet and outlet fittings. No cutting or modification required.

Production & Lead Time

CSF cooling systems are manufactured with strict quality control standards and performance validation. Inventory typically ships promptly when available. Each unit is pressure tested and inspected to ensure reliability under demanding conditions. Quality always comes first.

Fitment

Replaces OEM Part Numbers
17112284603
17112284604

Benefits

• Increased cooling capacity for tuned and track driven vehicles
• 2 row 42mm core for improved heat dissipation
• Larger tank volume for greater thermal stability
• 100 percent all aluminum TIG welded construction
• Modular design fits left or right side
• Integrated rock guard for added protection
• Direct drop in fit using OEM connections
• Individually leak and pressure tested
• Backed by a 2 year limited warranty

NOTE: OFF ROAD USE ONLY