Volkswagens and Audis use pink or purple antifreeze with a G12, G12 Plus, or G13 designation. If you need to add antifreeze/coolant due to a leak, it is very important to match the color of antifreeze already in your vehicle. Do not add green antifreeze if your vehicle has pink or purple already in it. Even a little is not okay. Green antifreeze reacts with pink and purple to form a jelly that can clog the heater core causing low to no heat. This jelly can also clog other small vent lines.
If you need to “top off” your vehicle’s antifreeze you can add a little bit of water, especially during the summer months, then schedule service to have the leak repaired.
Repairing the leak generally includes draining the cooling system, measuring the amount of pink or purple antifreeze and water, then adjusting the ratio to bring it back to a proper ratio of 50/50 mix—50% antifreeze and 50% distilled water.