This method does not need to disassemble and disassemble the engine, nor does it need to carry out tedious hydraulic seal tests on the cylinder head and cylinder block. During the inspection, the rubber tube of the air compressor is connected to the hose of the radiator and the compensation tank, and the compressed air is filled into the closed water-cooled circulating system with a pressure of 294 kPa (3 kgf/cm2). The following inspection can be carried out:

1. Inspection of external leak points

If there are leaks in the upper and lower storage chambers, radiators, connecting hoses, discharge switches, pumps and other places of the radiator, needle-shaped water column will be ejected, and the leak point can be clearly found.

2 Inspection of leak point inside airframe

Damage to the water channel of cylinder gasket leads to the penetration of coolant and lubricating oil, which makes the lubricating oil contain water, thinning the quality of oil and increasing the quantity. Sealing failure of wet cylinder liner results in loosening or rupture of cylinder liner and cylinder block. After removing the oil pan and filling the compressed air for inspection, it is easy to find the leakage point.

The insufficiency of pump water is usually due to blockage of water channel, slippage of impeller and shaft, leakage or slippage of transmission belt. Troubles can be eliminated by dredging water channel, reassembling impeller, replacing water seal and adjusting the tightness of fan transmission belt.

3. Inspection of leakage in cylinder head

The exhaust pipe emits white smoke when the engine works from the appearance. Remove the spark plug and detect water staining from the electrode. If the spark plug is not removed, only the exhaust pipe connector is removed. After filling the cooling system with compressed air, the engine is rotated, and water flows from the lower end of the exhaust pipe.