Each MMR cap starts life as a solid billet of 6061 aerospace-grade aluminium.
It's meticulously machined from this billet with the latest CNC 5-axis technology, before being polished, then gloss-anodised to stay beautiful year after year.

All MMR coolant caps arrive pre-sealed and pre-installed with an OE spec valve and internal spring. No need to remove the valve assembly from your OE cap. A true plug and play solution.

It has been designed to instantly give your BMW an under-bonnet boost in the aesthetic department, finished in a deep gloss black anodised finish.

Never again will you worry whether you tightened your expansion cap fully, as the cap contains complete OE replacement internals. The carefully considered design gives ample surface grip area for your fingers, making installation and filling your coolant that little bit easier.