- hydrometer for measuring coolant concentration or HAZET 4810-B measuring device for checking electrolyte density and coolant concentration. A suitable hydrometer can be used at a petrol station.
Necessary materials:
- antifreeze,
- distilled water.
4. Warm up the engine until the upper radiator hose is slightly warm. The temperature of the coolant in the expansion tank should be approximately +20°C.
5. Turn away, being careful, a cover of a broad tank.
Attention! Do not remove reservoir cap when engine is hot, see also «Coolant - level check».
6. Take the coolant from the expansion tank with a hydrometer and determine its density on the hydrometer scale (see illustration). In our climatic conditions, the coolant should not freeze at air temperatures down to -37°C, which is ensured by a 50% percentage of antifreeze and water.
7. Increase the percentage of antifreeze in the coolant, using the table below, if necessary.
Increasing the density of the coolant
Example: When measuring the density of a coolant in a car with a gasoline engine, it was found that the filled coolant provides frost protection only at an ambient temperature of -10°C.
To provide freeze protection down to -37°C, drain 2.1 liters of coolant from the system and fill the system with 2.1 liters of clean antifreeze.
Attention! The calculations in the table above are valid at a coolant temperature of +20°C.
Attention! Do not mix coolant of different brands and colors. This can cause significant engine damage. In the event that a coolant that does not meet the requirements of the vehicle manufacturer was mistakenly filled into the system, drain it immediately and flush the system with clean water.
8. Close the expansion tank cap and check the coolant level after a test drive.
Attention! If the concentration of antifreeze in the coolant is too high, its cooling effect decreases and the freezing threshold of the coolant in the system decreases. This is observed with the percentage of antifreeze in the coolant, starting at about 55% and above.