Pressure Testing Radiator Cap
WARNING: This page does not describe the selected car, but rather 16 other vehicles, including the 1984 Plymouth Turismo, 1984 Plymouth Reliant, 1984 Plymouth Horizon, 1984 Plymouth Gran Fury, and 1984 Dodge Rampage. However, it is still accessible from the selected car via links, so may be relevant.
A pressure testing tool is used to test both radiator cap and complete cooling system. Test as follows, following tool manufacturer's instructions.
Visually inspect radiator cap, then dip cap in water and connect to tester. Pump tester to bring pressure to upper limit of cap specifications. If cap fails to hold pressure within specifications, replace cap.
NOTE:
Wet cap gasket before testing.