Water THERMO Valves

While engine is cold, disconnect EGR control valve-to-No. 3 thermo valve vacuum tube. Disconnect No. 1 purge control valve-to-No. 3 thermo valve vacuum tube from thermo valve (under intake manifold).
Start engine and run at 1500 RPM. No vacuum should be felt at either port. See Fig 1 .

Fig 1: Testing Water Thermo Valve
Run engine until coolant temperature is 131°F (55°C).
With engine at proper temperature, vacuum should be felt. If valve does not respond as outlined, replace water thermo valve.