The 1985 VW Golf Cabriolet Mk1 was one of the first generations of water-cooled cars manufactured by Volkswagen. While the engine of these vehicles is normally cooled by a radiator, run under pressure and mounted at the front of the vehicle, the Car Spa radiator has been replaced with a spa bath, formed by inundating the vehicle’s interior.

Water is piped directly from the engine to jets in the vehicle’s rear seat. The pressurised circulation of water through the engine, coupled with the engine’s heat, delivers jets of hot water into the cabin of the vehicle. Both an electric and a mechanical water pump is fitted to the engine, as such the intensity of the jets responds to the acceleration of the vehicle.

Despite the removal of the radiator the car remains drivable, as the heat of the engine is regulated by the water of the spa - water and heat which is shared by the occupants of the vehicle. The water fits the contours of the body, just as it fits the interior of the engine. Depending on ambient conditions, left to run continuously the spa maintains a temperature of around 40 degrees Celsius, which is industry standard in Germany.