Surge Tank Cap Test

The surge tank cap maintains proper pressure, protects system from high pressure by opening a pressure valve, and protects coolant hoses from collapsing because of a vacuum.

1. Wash any sludge from surge tank cap and valve seat of vacuum pressure valve for surge tank cap. Check for any damage or deformity to vacuum pressure valve for surge tank cap. If any damage or deformity is found, replace cap. Install a suitable cooling system pressure tester to cap using Adapter (KM-471).
2. Pull vacuum pressure valve open. If surge tank cap does not seal properly, replace surge tank cap. Pressurize cap to 90-120 kPa (13.1-17.4 psi). Wait 10 seconds and check pressure held by tank cap tester. If pressure held by cooling system pressure tester falls below 80 kPa (11.6 psi), replace surge tank cap.