All four thermal valves are installed on the thermostat block under the manifold at battery level. The thermal valve system is designed to heat the coolant. While the engine is running, the thermal valves are supplied with 12 V voltage through three relays. One relay controls two thermal valves, each of the other two relays controls the operation of one thermal valve. This allows you to control one, two, three or all four thermal valves. When the thermal valves operate, the engine crankshaft speed increases to 900 min-1.
Thermal valves are turned off:
with preheating;
during subsequent heating;
at engine speed less than 700 min-1
Under the above conditions, the thermal valves are controlled depending on the air and coolant temperatures.