Thoroughly wash the cylinder block, clean the lubrication channels. After blowing and drying with compressed air, inspect the cylinder block. Cracks in any places of the cylinder block are not allowed.
If there is a suspicion that coolant has entered the crankcase, then check the tightness of the cylinder block on a special stand. To do this, after plugging the holes in the cooling jacket of the cylinder block, supply water at room temperature under a pressure of 0.3 MPa into it. Within two minutes, there should be no water leakage from the unit.
If oil gets into the coolant, then without completely disassembling the engine, check for cracks in the cylinder block in the areas of the oil channels. To do this, drain the liquid from the cooling system, remove the cylinder head, fill the cooling jacket of the cylinder block with water and supply compressed air to the vertical oil channel of the cylinder block. If air bubbles appear in the water filling the cooling jacket, replace the cylinder block.
Check the split plane of the cylinder block with the head using a ruler and a set of feeler gauges. The ruler is installed along the diagonals of the plane, in the middle in the longitudinal direction and across.
Cylinder repair. Check that the wear of the cylinders or liners does not exceed the maximum allowable - 0.15 mm. The cylinder diameter is measured by an inside gauge in four zones, both in the longitudinal and transverse directions of the engine.