Mishimoto Performance Auxiliary Radiator misMMRAD-F80-15A for 2015-2020 BMW F8X M3 and M4

The Mishimoto Performance Auxiliary Radiator, part number misMMRAD-F80-15A, is engineered for 2015-2020 BMW F8X M3 and M4 models equipped with the S55 engine. Designed for sustained track sessions and aggressive street driving, this upgraded radiator increases cooling capacity where the factory auxiliary unit can heat-soak. Its larger aluminum core provides additional thermal headroom, helping maintain consistent engine temperatures during repeated high-load use.
The core delivers 9% more volume and 32% more external tube area than the stock auxiliary radiator for improved heat rejection. Strutted tubes reinforce the core against vibration and road impacts, while aluminum TIG-welded end tanks replace the factory plastic components that can crack after repeated heat cycling. A removable stone guard helps protect the exposed radiator face from road debris, making this unit well suited for demanding driving environments.
A robust bracket design allows the Mishimoto misMMRAD-F80-15A to fit either the driver-side or passenger-side auxiliary radiator location. The direct-fit design installs in the factory position without cutting, fabricating, or adapter work. Built for reliable performance across varied driving conditions, this Mishimoto radiator is backed by the Mishimoto Lifetime Warranty. Professional installation is recommended, and vehicle-specific fitment should be verified before ordering.

Features:

• Built for back-to-back track sessions: Adds cooling capacity to help the S55 maintain consistent temperatures during sustained high-load driving.

• Reinforced strutted tubes: Strengthen the radiator core against vibration and impact from road use.

• Increased heat rejection: Provides 9% more core volume and 32% more external tube area than the stock auxiliary radiator.

• Driver- or passenger-side installation: A robust bracket design allows one radiator to fit either factory auxiliary radiator location.

• Direct-fit installation: Fits the factory auxiliary radiator position on 2015-2020 BMW F8X M3 and M4 models without cutting, fabrication, or adapters.

• TIG-welded aluminum end tanks: Replace failure-prone plastic factory tanks for improved durability under repeated heat cycling.

• Removable stone guard: Helps shield the exposed radiator core from road debris.

• Mishimoto Lifetime Warranty: Provides long-term coverage for added ownership confidence.