Mishimoto offer this Liquid Chill Radiator Coolant Additive as a cheap and easy upgrade for any radiator.
As well as improving the design of the radiator itself, you can also boost the efficacy of the coolant you're running in it.
Suitable for adding to all coolant types, this additive is proven to reduce temperatures of all liquid cooled engines.
It also contains corrosion inhibitors to help keep your cooling system in tip top condition.
118ml.