Operation of the cooling system

Opel Vectra/Calibra engine cooling system - with forced circulation of the coolant and automatic regulation of its temperature. The coolant contains anti-corrosion additives and should be used in both winter and summer. Before the start of the cold season, the density of the liquid should be checked. The plug of the expansion tank has a safety valve that keeps the pressure in the system within 1.0-1.3 bar. Increased pressure raises the boiling point of the coolant to 125°C. In order to prevent the occurrence of vacuum in the hoses of the system when the engine is cooled, there is a check valve in the plug, which opens air into the cooling system when the pressure in it drops to 0.06-0.10 bar.

The coolant flows through the radiator from top to bottom, being cooled by the air flow blowing over it. The system pump pumps fluid from the bottom of the radiator and delivers it through a hose to the head and cylinder block.

The cylinder head is designed in such a way that the coolant through the internal channels is supplied directly to the valves, cooling them. From here, the liquid enters the cylinder block. After the cylinders have cooled, the liquid enters the thermostat and, having passed through it, it enters the upper part of the radiator through a hose. The cycle is repeated.

When the coolant temperature is below 92°C, the thermostat is closed. In this case, the liquid is sucked in by the pump through the bypass channel directly at the thermostat and is fed into the channels of the cylinder head. Thus, a uniform and fast warm-up of the engine is achieved. When the liquid reaches a temperature of about 92°C, the thermostat begins to open, and at a temperature of 107°C it is already fully open, and the coolant passes through the radiator.