In the instrument cluster of any car there is a coolant temperature indicator 1. In addition, there is a signal lamp 2 for engine overheating in the lamp block of the instrument cluster of your car. If the engine overheats, the pointer scale is shaded completely (under normal temperature conditions, only the four lower divisions of the scale are shaded) and the warning light comes on.
Checking the cooling system
At the first sign of overheating, if the temperature indicator scale is completely shaded, but there are no clouds of steam coming out from under the hood, turn on the maximum interior heating mode, see fig. «Heating (conditioning) and interior ventilation». 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 vehicle'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, out of the roadway. Let the engine run for a couple of minutes at normal idle speed with the heater turned on at full power.
Attention! Do not stop the engine immediately! The only condition is to maintain the tightness of the cooling system. If a hose has burst or jumped off, or another leak has formed, in addition to the ejection of fluid from under the expansion tank cap, the engine will have to be stopped immediately.
After the overheated engine stops, local overheating of the coolant begins at the points of its contact with the most heat-stressed engine parts and the formation of vapor locks. This phenomenon is called «heat stroke».
1. Stop the engine.
2. Open the hood and inspect the engine compartment. 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, thermostat.
Attention! Never open the expansion tank cap immediately. The liquid in the cooling system is under pressure, when the plug is opened, the pressure will drop sharply, the liquid will boil and its splashes can scald you. If you want to open the cap of the expansion tank on a hot engine, first put a thick thick rag on top and only then carefully turn the cap.
3. Look under the instrument panel on the passenger side and determine if there are any leaks or traces of coolant flowing from the heater radiator under it.
If a coolant leak is detected, the burst hose can be temporarily repaired with adhesive tape.
Note. Especially well suited for this purpose reinforced (e.g. silver) adhesive tape, which can be purchased at car dealerships.
A radiator, thermostat or heater leak 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! Prolonged 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 the resource. Never add cold water to an overheated engine. The engine must cool down with the hood open for at least 30 minutes.
4. The engine can overheat if the thermostat that controls the flow of fluid in the cooling system through or past the radiator fails (to accelerate the warm-up of a cold engine). To check the thermostat, on a warm engine, check the temperature of the lower hose connecting the radiator to the engine by touch. If the lower radiator hose is cold, the thermostat is bad and there is no circulation through the radiator.
5. Very often, the cause of overheating of the engine, the cooling system of which is equipped with an electric fan, is the failure of the fan.
6. Start the engine, monitor the temperature and note if the cooling fan turns on when the engine overheats. If it does not turn on, then the reasons may be a faulty additional resistance, a blown fuse, faulty turn-on relays, oxidized contacts in the wiring harness block, or a burnt out electric motor.
7. Replace fuse 2 in the fuse and relay mounting block installed in the engine compartment. If the fan still does not start after replacing the fuse, replace relays 1 and 3 in the same mounting block. If the fan does not start after replacing the fuse and relay, check the motor by taking two additional wires and powering it directly from the battery. Wires must be securely fastened and insulated.
Attention! Do not allow wires to short circuit with each other! Pay attention to the polarity of the connection: the electric motor must rotate so that the fan blows air through the radiator onto the engine, and the directions of the generated flow and the incoming (track) air flow matched.
If the electric motor starts running, the wiring or the relay for turning on the cooling fan is faulty; if not, the wiring or the motor itself is also faulty. Relay and motor not repairable, replace as an assembly (see section «electrical equipment»).
Note. There are two valves in the plug of the expansion tank - inlet and outlet. The exhaust valve plays a big role in ensuring optimum engine temperature. It maintains an excess pressure of at least 0.13–0.15 MPa in the system (1.3–1.5 kgf/cm2), providing an increase in the temperature of the start of boiling of the coolant and preventing intense vaporization. Unfortunately, when the valve is stuck in the closed position during overheating, a significant overpressure occurs - more than 0.15 MPa (1.5 kgf/cm2), which can lead to a rupture of the expansion tank or a breakdown of one of the hoses. In turn, the jamming of the valve in the open position leads to premature boiling of the coolant.
Therefore, once a year, rinse the plug of the expansion tank with running water. If in doubt, replace the plug. It is obvious that if, on an overheated engine, remove the plug of the expansion tank and in time this action will coincide with «heat stroke», then boiling of the liquid and the formation of air pockets in the cooling system will be guaranteed. Blow out the radiator cells with compressed air once a year (e.g. from a compressor), directing the jet first towards the oncoming air flow, and then in its direction to remove dirt, adhering insects and road debris from the surface of the radiator. So you can partially restore the efficiency of the radiator.