THERMO Valve

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