do88 Auxiliary Radiators | BMW G8X M2 M3 M4
Improve engine cooling performance on your S58-powered BMW with the do88 Performance Auxiliary Radiators, designed to provide increased cooling capacity for tuned, high-performance and track-driven G8X vehicles.
The kit replaces both factory auxiliary radiators with larger, full-aluminium units featuring increased core volume, greater active cooling area and a direct-fit design.
Improved S58 Engine Cooling
The BMW S58 cooling system uses three front-mounted engine coolant radiators: one large central radiator supported by two smaller auxiliary radiators positioned ahead of the front wheels.
As engine output increases, so does the amount of heat the cooling system must manage. During demanding street driving, track use or other sustained high-load conditions, maintaining consistent coolant temperatures becomes increasingly important.
The factory auxiliary radiators utilise relatively slim cores and plastic end tanks. The do88 replacements have been developed to significantly increase cooling capacity while maintaining compatibility with the factory cooling system.
43% Larger Core Volume
Taking advantage of the available space within the G8X front cooling package, do88 has increased both the frontal surface area and thickness of the auxiliary radiator cores.
Each radiator uses a 48 mm thick, two-row core, resulting in:
- 43% greater core volume compared with the factory radiator
- 13% greater active cooling area
- Increased coolant capacity
- Improved heat dissipation under sustained load
The increased cooling capacity makes these radiators particularly suited to tuned S58 applications where the factory cooling system is subjected to greater thermal loads.
Full Aluminium Construction
The factory plastic end tanks are replaced with a robust full-aluminium design.
Each radiator features TIG-welded aluminium end tanks together with CNC-machined mounting hardware and connections, providing increased durability for high-performance applications.
Direct-Fit Installation
The do88 Performance Auxiliary Radiators are engineered as direct replacements for the factory units.
They feature OE-style Quick Connect inlet and outlet connections, together with CNC-machined mounting brackets for straightforward installation.
The original BMW rock guards can also be retained, helping protect the upgraded radiator cores from stones and road debris.
Both left and right radiators are included, allowing the cooling system to be upgraded evenly rather than replacing only one side.
Key Features
- Supplied as a pair – left and right auxiliary radiators
- 43% larger core volume than the factory radiators
- 48 mm thick two-row cores
- 13% increased active cooling area
- Increased coolant capacity
- Improved heat dissipation
- Full aluminium construction
- TIG-welded aluminium end tanks
- CNC-machined mounting brackets
- OE-style Quick Connect coolant connections
- Compatible with factory BMW rock guards
- Direct replacement for the factory auxiliary radiators
- Designed for tuned and high-performance S58 applications
Vehicle Compatibility
Designed for 2021+ BMW G8X S58 applications, including:
- BMW M2 G87
- BMW M3 G80
- BMW M3 Touring G81
- BMW M4 G82
- BMW M4 Convertible G83
Always confirm compatibility with your specific vehicle before ordering.
Important Information
This product is intended for performance use and should be installed by a qualified professional.
It is the customer’s responsibility to ensure compatibility with their specific vehicle prior to purchase. If you are unsure, please contact us before ordering.
Gridline Custom Motorsports is not responsible for issues arising from incorrect installation, misuse, or improper product selection.
Due to the nature of performance parts, some items may be special order and subject to supplier availability and lead times.