Coolant Vacuum Switch Cold Closed (CVSCC) Valve Test

BENCH TEST
Place CVSCC valve in ice and cool valve below 40° F. Using a suitable vacuum pump and gauge tool C-4207 or equivalent, apply vacuum of at least 10 inches Hg to valve nipple corresponding to the blue striped hose. If vacuum reading drops more than 1 inch in one minute, replace CVSCC valve.

ON-VEHICLE TEST
Prior to checking valve operation, ensure vacuum hoses are properly routed and in good condition. Also, check engine coolant level and correct as necessary.
With valve installed, disconnect molded connector from valve and attach a 1/8 inch hose to lower port of valve. With radiator top tank warm to the touch, but no warmer than 75° F, attempt to blow through hose. If it is not possible to blow through hose, the valve is defective and must be replaced.