Radiator is a heat exchanger through which heat from the engine liquid is transferred to the air. The radiator consists of upper tank 9 and lower tank 15, which are connected by the core of the radiator 12.

A filler neck 8, closed by a stopper 7 and a pipe for connecting a flexible hose supplying heated fluid to the radiator, is soldered to the upper tank.
The filler neck has a hole for the steam outlet on the side.

A branch pipe of the outlet flexible hose 13 is soldered to the lower tank. Side racks 6 are attached to the lower and upper tanks are connected by a plate soldered to the lower tank. Racks and plates form the radiator frame.

Engine Radiator Construction

1. parts of radiator; b – steam exhaust valve open; c – air inlet valve open; 1- housing; 2 – radiator gills; 3 – draught; 4 – handle; 5 – fixator; 6 – stand; 7 – radiator filler cap; 8 – radiator filler neck; 9 – upper radiator tank; 10  and 13 – flexible hoses; 14 – radiator drain cock; 15 – lower radiator tank; 16 – quide cover; 17 – steam pipe; 18 – radiator filler cap housing; 19 – spring of steam valve; 20 – stand; 21 – lock spring; 22 – steam valve; 23 – steam valve rubber gasket; 24 – air valve rubber gasket; 25 – air valve; 26 – spring of air valve; 27 – air valve seat; 28 – air inlet.

There are some cores of radiator: tubular plate core and tubular tape core. The core of gilled tube radiator consists ofseveral rows of tubes soldered into the upper and lower tank. Thin cooling plates made of brass, aluminum and copper are installed on the tubes.

The radiator is connected to the engine cooling jacket by tubes and flexible hoses.

Radiator gills 2 are installed in front of the radiator to control the amount of air passing between the radiator tubes. The handle 4 completely opens the radiator gills and air can freely pass between the radiator tubes. And if you close the handle 4 the radiator gills are closed.

The radiator filler neck 8 is hermetically sealed with a radiator filler cap isolating the engine cooling system from the environment.

The radiator filler cap

The radiator filler cap consists of a housing 18, steam 22 and air 25 valves and a locking spring 21. On the stand 20, by means of which a locking spring is attached to the housing, a steam valve is installed, pressed by the spring 19. The air valve 25 is pressed by a spring 26 against the seat 27 pressed into the steam valve. A tight connection of valves with seats is achieved by installing rubber gaskets 23 and 24.  If the rubber gaskets are damaged or destroyed, the cooling system becomes open and the water boils at 100 degrees Celsius. So the liquid boils and the vapor pressure in the radiator increases. When the pressure increases to 145-160 kPa, the steam valve 22 is opening overcoming the resistance of the spring 19. The engine cooling system connects with the environment and the steam exits the radiator through a steam pipe 17. After the engine stops working, the liquid cools, the steam condenses and a vacuum is created in the engine cooling system.

When the pressure drops to 1-13 kPa, the air valve opens and air enters the radiator through the openings 28 passes through the steam pipe. Steam and air valves prevent possible damage to the radiator under the influence of both external and internal pressure.