The 2003 Volkswagen Jetta had plenty of options to suit just about any buyer, including a laundry list of engines. This list of engines included the base, 115-horsepower, 2.0-liter engine; a 180-horsepower, 1.8-liter engine; a 200-horsepower, 2.8-liter engine and a 90-horsepower, 1.9-liter diesel engine. Like many other German cars, the 2003 Jetta uses a proprietary coolant that is not compatible with any other coolant.
The 2003 Volkswagen Jetta uses a vehicle-specific coolant that is informally known as "G12" and is available from any Volkswagen parts department under part No. G 12 A8D TL 774 D or G 012 A8 D. You can identify this coolant by its red color. The correct mixture for the 2003 Jetta is 50-50 G12 coolant and distilled water.
