Turn on the hazard warning lights, depress the clutch pedal and, using the car's momentum, try to carefully move to the edge of the roadway and stop as far to the right as possible at the side of the road, and if possible, outside the roadway. Let the engine run for a couple of minutes at normal idle speed with the heater on full blast.
Attention! Do not stop the engine immediately! The only condition is to maintain the tightness of the cooling system. If a hose bursts or comes off, or another leak occurs, other than fluid being released from under the expansion tank cap, the engine will have to be stopped immediately!
After an overheated engine stops, local overheating of the coolant begins in places where it comes into contact with the most heat-stressed parts of the engine and vapor locks form. This phenomenon is called heat stroke.
1. Stop the engine.
Figure 3.2. Inspection points in the engine compartment
2. Open the hood and inspect the underhood space (figure 3.2). Determine where the steam is coming from. When inspecting the engine, pay attention to the presence of coolant in the expansion tank, the integrity of the rubber hoses, radiator, and thermostat.
Warning! Never open the expansion tank cap immediately. The liquid in the cooling system is under pressure, when you open the plug the pressure will drop sharply, the liquid will boil and its splashes can scald you. If you want to open the expansion tank cap on a hot engine, first put a thick, dense rag on top and only then carefully unscrew the cap.
Note: The expansion tank cap valve plays a major role in ensuring the optimal temperature regime. It maintains an excess pressure of at least 0.1 MPa in the system (1.1 kgf/cm²). In this case, the boiling point of water increases to 120°C, and the coolant to 130°C. Unfortunately, when the valve is jammed in the closed position due to overheating, a significant excess of excess pressure occurs - more than 0.2 MPa (2 kgf/cm²), which can lead to a rupture of the expansion tank or a tear in one of the hoses.
Therefore, once a year the expansion tank cap must be washed with running water. If in doubt, replace the plug. Obviously, if you remove the expansion tank cap on an overheated engine and this action coincides with thermal shock, boiling of the liquid and the formation of air locks in the cooling system will be guaranteed.
Once a year, flush the radiator cells with a high-pressure water jet (at a special car wash), directing the stream first towards the oncoming air flow, and then in its direction to remove dirt, stuck insects and road debris from the radiator surface. In this way, the efficiency of the radiator can be partially restored.
Note: If coolant leaks are found, a burst hose can be temporarily repaired with tape. Reinforced steel is especially well suited for this purpose (usually silver in color) adhesive tape, which can be purchased at auto stores.
A leak in a radiator, thermostat or heater is quite difficult to fix on the spot, so in such a situation it is necessary to add water to the cooling system and carefully monitor the temperature gauge while driving, periodically restoring the level in the cooling system.
Attention! Long-term use of water instead of coolant leads to scale formation in the engine cooling system, deterioration of its cooling and, as a result, reduction of service life.
Caution: Never add cold water to an overheated engine. The engine must cool down with the hood open for at least 30 minutes.
3. The engine may overheat if the thermostat, which regulates the flow of fluid in the cooling system through or past the radiator, fails (to speed up the warming up of a cold engine). To check the thermostat, you need to check the temperature of the hose connecting the thermostat housing to the radiator on a warm engine. If the hose is cold, the thermostat is faulty and there is no circulation through the radiator.
4. Very often the cause of overheating of an engine, the cooling system of which is equipped with an electric fan, is the failure of the fan. Start the engine, monitor the temperature and notice whether the cooling fan turns on when the engine overheats.
5. If the fan does not turn on, the fuse may be blown, the relay may be faulty, the electric motor may be burnt out, or the wiring may be faulty.
6. Check the integrity of the electrical wiring and the reliability of the electrical connectors.
7. If the wiring is OK, check the engine cooling fan fuse and replace it if faulty.
8. If the fuse is good, try replacing the fan relay.
9. If the fan still does not turn on, check the motor. To do this, take two additional wires and supply power to it directly from the battery. The wires must be securely fastened and insulated.
Attention! Do not allow wires to short-circuit each other!
Attention! Pay attention to the polarity of the connection: the electric motor must rotate so that the fan forces air through the radiator onto the engine, and the directions of the generated air flow and the oncoming (path) flow coincide.
10. If the electric motor starts to work, the wiring is faulty; if not, the wiring or the electric motor itself is also faulty. The relay and electric motor cannot be repaired, replace them as an assembly (see section. "Electrical equipment").
Note: It is permissible to drive to the repair site with the electric motor connected directly to the battery. Upon arrival, do not forget to disconnect the electric motor from the battery, otherwise it will discharge it.