Where is the coolant cap located on Audi 1.8t 2003?

The coolant cap on a 2003 Audi 1.8T is located on the coolant expansion tank, which is typically found on the driver's side of the engine bay. The expansion tank is a translucent plastic reservoir, allowing you to easily check the coolant level. The cap itself usually has a warning label indicating that it is under pressure. Always ensure the engine is cool before removing the cap to avoid injury.