Radiator Cap
WARNING: This page is about a different car, the 1983 Volkswagen Vanagon, 1983 Volkswagen Rabbit, 1983 Volkswagen Quantum, 1983 Volkswagen Pickup, and 1983 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.
Cap opens at 17-21 psi (1.2-1.5 kg/cm2 ) for Quantum, 11-16 psi (.8-1.1 kg/cm2 ) for Vanagon, and 17-19 (1.2-1.3 kg/cm2 ) for all others.