The vehicle's instrument cluster contains a coolant temperature gauge. If the engine overheats, the gauge needle approaches zone H.
Checking the cooling system
At the first signs of overheating, if the temperature gauge needle has moved into zone H, but no clouds of steam are escaping from under the hood, turn on the maximum cabin heating mode (see "Heating, air conditioning and ventilation system of the passenger compartment"). This is necessary in order to reduce the temperature of the coolant in the engine cooling system.
Turn on the hazard warning lights, depress the clutch pedal, then, 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 curb, and if possible, outside the roadway. Let the engine run for a couple of minutes at normal crankshaft speed at idle, with the heater on full power,
Warning: 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, except for the liquid ejected 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 the places where it contacts the most heat-stressed engine parts and vapor locks form. This phenomenon is called thermal shock.
1. Stop the engine.
2. Open the hood and inspect the underhood space. Determine where the steam is coming from. When inspecting the engine, pay attention to the presence of coolant in the expansion tank 1 (Fig. 3.2), the integrity of the rubber hoses, radiator 2 and thermostat 3.
Warning: Never open the expansion tank cap straight away. The liquid in the cooling system is under pressure, and when you open the cap, the pressure will drop sharply, the liquid will boil, and its splashes can burn 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 turn the cap.
3. A hose connected to a tray installed under the heater radiator is passed through the hole in the front shield into the engine compartment. If coolant flows out of the hole in the hose, the radiator is damaged.
If a fluid leak is detected, the burst hose can be temporarily repaired using tape.
Helpful Hint: Reinforced concrete is especially suitable for this purpose (for example, silver 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,
Warnings: Long-term use of water instead of antifreeze leads to the formation of scale in the engine cooling system, deterioration of its cooling and, as a result, to a reduction in service life.
Never add cold water to an overheated engine. Allow the engine to cool for at least 30 minutes with the hood open.
4. 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 upper hose connecting the thermostat to the radiator on a warm engine. If the upper radiator hose is cold, the thermostat is faulty, there is no circulation through the radiator.
5. Very often the cause of engine overheating is the failure of the electric fan.
6. Start the engine, monitor the temperature and check whether the cooling fan turns on when the engine overheats. If it does not turn on, the cause may be a blown fuse or fusible link, oxidation of the contacts in the wiring harness block, or a burnt out electric motor. Replace fusible link #45 and fuse #46 (see "Location of fuses, fuse links, relays and their replacement") in the fuse box installed in the engine compartment. If the fan does not start working after replacing the fuse and fuse, check the electric motor by taking two additional wires and supplying power to it directly from the battery. The wires must be securely fastened and insulated.
Warnings: Do not allow the wires to short-circuit each other! 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.
If the electric motor starts to work, the wiring or the cooling system fan relay is faulty; if not, the wiring or the electric motor itself is also faulty. The relay and the electric motor are not repairable, replace them (see section. "Electrical equipment").
Helpful tips: There are two valves installed in the expansion tank cap - inlet and outlet. The outlet valve plays a major role in ensuring the optimal engine temperature. It maintains excess pressure in the system of at least 0.13-0.15 MPa (1.3-1.5 kgf/cm²), ensuring an increase in the temperature at which the coolant begins to boil and preventing intensive vaporization. When the valve is jammed in the closed position due to overheating, a significant excess of excess pressure occurs - more than 0.15 MPa (1.5 kgf/cm²), which can lead to a rupture of the expansion tank or a tear in one of the hoses. In turn, jamming of the valve in the open position leads to premature boiling of the coolant.
Therefore, once a year, wash the expansion tank cap with running water. If in doubt, replace the cap. Obviously, if you remove the expansion tank cap on an overheated engine and this action coincides with a thermal shock, then you are guaranteed to have boiling liquid and air locks in the cooling system.
Blow out the radiator cells with compressed air once a year (for example, from a compressor), 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. This can partially restore the radiator's efficiency.