The engine starting heater is designed to warm up the engine before starting it at low ambient temperatures

The heater runs on the fuel used for the engine

The heater can warm up the engine, the cooling system of which is filled with water or antifreeze.

The heater is installed on the engine on the right side (Fig. 1).

The heater is a non-separable boiler 15, consisting of a combustion chamber, a flame tube, a flue and two interconnected liquid jackets (heat exchanger).

The boiler is constantly included in the engine cooling system.

ZIL-131 heater

Fuel is supplied to the combustion chamber of the boiler from tank 1 by gravity. To control the fuel supply, a solenoid valve 23 with an adjusting needle 4 and a fuel filter is installed.

The valve works as follows: when the switch 21 of the control panel is turned off, the core closes the fuel line under the action of a spring; when the switch is turned on, current flows into the coil, the core is pulled, and the fuel freely enters the combustion chamber of the heater.

Air is supplied to the combustion chamber by a fan installed under the engine hood.

The mixture is initially ignited by glow plug 11.

After a stable combustion is established in the chamber, the candle turns off, and further combustion of the fuel occurs from the previously lit flame.

An additional control resistance installed on the heater control panel is connected in series to the spark plug circuit. The glow of the resistance spiral is used to judge the operation of the candle.

After the fuel is ignited from the heater plug, the resulting hot gases pass in a swirling flow through the flame tube and give off heat to the heated liquid poured into the boiler.

Gases passing through the exhaust pipe are directed by tray 13 under the engine crankcase, where they are used to heat the oil in the crankcase.

The liquid cavity of the heater boiler is connected to the engine cooling system through pipes 12 and 17.

On the engine shield, a heater control panel 18 is installed in a separate casing, on which a candle switch 20, a control coil 19 and a switch 21 are installed.

The switch has three positions:

  • - position 0 - everything is off (the switch knob is pressed all the way);
  • - position 1 — the fan motor is on (the handle is extended halfway);
  • - position II - the fan motor and the magnetic valve are on (the handle is pulled out to the full).

The electrical diagram of the heater control panel is shown in fig. 2.

Scheme of the ZIL-131 heater control panel

The procedure for starting the engine when using the starting heater

The procedure for starting the engine when using water as a coolant. Warming up and starting the engine must be done in the following order:

  • 1. Prepare water to fill the entire cooling system.
  • 2. Close the radiator shutters, open the engine hood, in case of strong wind, take measures to ensure that the open hood is not damaged.
  • Turn off the oil cooler and put an insulating cover on the radiator grille.
  • 3. Open the plugs of the radiator and the filler funnel of the heater, close the valve of the heater boiler and the valve of the heater pipeline.
  • If the taps are frozen, then you should close them when the engine warms up, after water comes out of the taps.
  • Leave the radiator drain cock open.
  • 4. If there is no fuel in the tank or it is not enough, fill the tank. When filling the tank, make sure that it is not overfilled and that fuel does not spill. Tank capacity 2 l.
  • 5. Pour 1.5 liters of water into the heater boiler through funnel 3 (see Fig. 1).
  • 6. Open tap 24.
  • 7. Move the handle 21 of the switch to position II for 15-20 seconds; at the same time, the fan motor is turned on, the electromagnetic valve opens and the asbestos lining of the combustion chamber is wetted with gasoline.

In very low temperatures, this time should be increased to 60 seconds.

Set the switch to position 0 and turn on the spark plug switch 20 while keeping it pressed.

As soon as the control coil glows to a light red color, gasoline ignites in the combustion chamber; this will hear a pop.

After popping, start the heater by moving the switch knob 21 to position II.

When stable operation of the heater is reached, turn off the candle by releasing switch 20.

  • 8. If the heater according to what-for some reason it did not start working, restart it.

If water freezes in tubes 12 and 17 (checked by touch), it must be thawed by periodically turning on the heater for 1-2 minutes at intervals of 2-4 minutes and blowing air into the heater boiler between turns on by a fan.

It is impossible to allow the heater to operate for a long time with frozen pipes (more than 2 minutes).

  • 9. After 1-2 minutes after starting the heater, it is necessary to additionally pour 6-8 liters of water into the engine through the boiler funnel, close the funnel plug and continue warming up the engine. The hood should be closed while the engine is warming up.

If the heater stalls when the hood is closed, the hood should be left ajar with some object under it. Water must be poured carefully, without spilling it on electrical equipment.

  • 10. When the water in the engine heats up and steam appears from the radiator filler neck, crank the engine crankshaft several times with the start handle.

The shaft of the engine ready to start turns easily, and compression resistance is clearly felt on the starting handle.

  • 11. Turn off the heater by moving the switch knob 21 to position I (to blow the boiler) and close the cock 24.

Approximately 50-60 seconds after the humming of the flame in the heater boiler stops, turn off the fan by moving the switch knob to position 0.

Flame ejection and burning of the air supply hose 10 may occur due to non-observance of the specified order of turning off the heater.

  • 12. Start the engine and close the radiator drain valve. If it is frozen, close it after thawing when pouring water.
  • 13. While warming up the engine at medium speed, pour additional water into the engine through the filling funnel until it is completely filled and close the funnel plug.

Then pour water into the radiator until the volume of the cooling system is filled and close the radiator cap. If there is an expansion tank, pour 2 liters of water into it.

  • 14. After warming up the water in the engine cooling system to a temperature of 60-70 ° C (according to the coolant temperature indicator on the instrument panel), you can start driving the car.
  • 15. Drainage of water from the cooling system must be carried out through the radiator valve, boiler valve 14 and heater pipeline valve 7 by turning the valve control knob 6; in this case, it is necessary to open the cap of the radiator or expansion tank.

If there is an expansion tank, the water must also be drained through the tap located at the bottom of the expansion tank.

The procedure for starting the engine when using antifreeze to cool the engine.

When using antifreeze as a coolant, preparation for starting the engine should be carried out as indicated above, with the exception of paragraphs. 1,3, 5, 9 and 13.


The main defects of the cylinder head that can be eliminated by repair include: warping of the plane of contact with the cylinder block, wear of seats and valve guides

UAZ vehicles are equipped with three types of mechanical three-shaft gearboxes: