S63TU4 Billet Coolant Reservoir


The F90 RK Billet reservoir is designed and machined in house to remedy the failing stock plastic reservoir for your M5/M8.

Raw and Black – on Backorder until 05/10/2024



S63TU4 Billet Coolant Reservoir

Billet reservoir designed and machined in house to remedy the failing stock plastic reservoir. Our all metal construction reservoir ensures leaks are not an issue anymore. Constructed of 6061 billet aluminum, you know you have a lifetime product and don’t need to worry about leaks anymore. Utilizing the stock cap also retains the pressure bleed off like designed by the OEM. All of the OEM connecting points are utilized and the quick connect fittings slip right on. This is a plug and play solution which even utilizes the stock sensor ensuring there won’t be any issues with level readings.


The OEM plastic reservoir is known to leak causing damage of the injectors and coils. This leads to vehicle downtime and potential engine damage. Simply replacing the OEM reservoir with another one is an unknown with how long it may last.


  1. 6061 billet CNC construction
  2. OEM factory cap retained
  3. OEM connections utilized like stock
  4. OEM sensor utilized for level reading
  5. O-ring sealing to ensure no leaking
  6. Internal baffling to dampen fluid transfer throughout the reservoir


  • MSRP $1250
    • Black Anodized Coating – $100

Models Supported

– 2018+ | M5 | F90
– 2019+ | M8 Coupe, Convertible, & Gran Coupe | F91, F92, F93


  • The customer will have to re-use the stock coolant sensor probe, which pulls out of the OEM reservoir. In certain cases, it does not slide out smoothly and you may need to trim around the sensor to remove it. We currently don’t sell the o-ring, you’ll need to measure it and source a replacement local if needed. Sorry for the inconvenience.

Additional information

Weight 15 lbs
Dimensions 12 × 12 × 6 in

Raw, Black, Red, Blue


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