THERMO Valve

The Thermo valve senses engine coolant temperature which prevents EGR operation below preset values. When engine warms, thermo valve opens, supplying vacuum to the EGR valve. At temperatures below 131°F (55°C) thermo valve is open and vacuum is vented so no vacuum is supplied to the EGR valve. At temperatures above 131°F (55°C) the thermo valve closes and normal EGR operation takes place.