Your vehicle's instrument cluster is equipped with a coolant overheating warning light that comes on when the coolant temperature approaches a critical level.
Checking the cooling system
At the first signs of overheating, if the engine overheating warning light comes on, but no clouds of steam are coming out from under the hood, turn on the maximum cabin heating mode, see. "Heating (conditioning) and 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 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: If the cooling system is not sealed properly (a hose has burst or come off, or another leak has formed, in addition to the liquid being released from under the expansion tank cap), the engine will have to be stopped immediately. In other cases, do not stop the engine 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 escaping from. When inspecting the engine, pay attention to the presence of coolant in the expansion tank, the integrity of the rubber hoses, radiator, thermostat.
WARNING: Never open the expansion tank cap immediately. The liquid in the cooling system is under pressure, when you open the cap 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 turn the cap.
3. Look under the dashboard to see if there is a leak or traces of coolant leaking from the heater radiator.
If a coolant leak is detected, the burst hose can be temporarily repaired with tape.
USEFUL TIP: 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. Let it cool down with the hood open for at least 30 minutes.
4. A break or loosening of the alternator and water pump drive belt almost always leads to engine overheating. If the belt breaks or is worn to the point that the automatic tensioner does not provide normal belt tension, replace the belt (see "Replacement of auxiliary drive belts").
5. 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 to the radiator on a warm engine. If the radiator hose is cold, the thermostat is faulty, there is no circulation through the radiator.
6. Very often, the cause of overheating of an engine whose cooling system is equipped with an electric fan is the failure of the fan. Start the engine, monitor the temperature and pay attention to whether the cooling system fan turns on when the engine overheats.
7. If the fan does not turn on, check the integrity of fuse links No.39 and 40 in the engine compartment mounting block, as well as the reliability of the fastening of relays No.53 and 61 of the radiator fan of the cooling system in the engine compartment mounting block.
8. If the fuse links are in good condition and the relay is securely inserted, remove the expansion tank (see "Removal and installation the expansion tank",) and check the reliability of the connection of the wiring harness block with the connector of the additional resistance of the electric fan.
9. If all checks are inconclusive, check the fan motor. To do this, disconnect the wiring harness connector from the additional fan resistor connector...
10. ...then press the lock and disconnect the additional resistance from the fan casing.
11. Take two additional wires and apply power directly from the battery to the terminals of the additional resistance. The wires must be securely fastened and insulated.
WARNING: Do not allow wires to short-circuit each other!
12. If the electric motor does not start, replace it (see "Removal and installation of the electric motor of the radiator fan of the engine cooling system and its additional resistance"). If the electric motor starts working, it means that it is working properly. In this case, check and restore the electric circuit of the electric fan (see "Diagnostics of faults of on-board electrical equipment").
USEFUL TIPS: There are two valves installed in the expansion tank cap - an inlet and an outlet valve. The outlet valve plays a major role in ensuring the optimal temperature regime of the engine. It maintains excess pressure in the system of at least 0.145 MPa, ensuring an increase in the temperature at which the coolant begins to boil and preventing intensive vaporization. Unfortunately, when the valve gets stuck in the closed position during overheating, a significant excess of excess pressure occurs - more than 0.15 MPa, 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 boiling of the liquid and the formation of air locks in the cooling system are guaranteed.
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.
The original article is on the website: ChevyMan.ru