A set of silicone coolant hoses for the Mk7 GTI. These hoses are lined with Fluorosilicone.

Some of the first vehicle coolants or antifreezes contained methanol which is still found in windshield washer fluid. As these mixtures require constant replenishment due to the evaporative properties, and can increase the corrosion of aluminium, which at this time become more widely used, a new coolant was developed. This was the Ethylene Glycol mixtures, though again whilst less corrosive it still required regular attention to maintain its antifreeze properties. More recently OAT or Organic Acid Technology coolants have been developed and used. These are normally orange in colour to differentiate them from the glycol-based coolants which are green or yellow. OAT coolants have an extended service life of around five years use. Whilst standard silicone hoses have a high resistance to the Ethylene Glycol coolants, they can quickly deteriorate, if not protected, when OAT coolants are used. It is for this reason that our hoses have an internal lining of Fluorosilicone to protect and ensure the longevity of the hose.