Thoroughly flushing and cleaning the cylinder block (especially his oil channels), start inspection and testing. First of all, it is necessary to check if there are visible cracks on the cylinder block. If they are, then the cylinder block must be replaced.
If there is a suspicion that coolant has entered the crankcase, then it is recommended to check the tightness of the cylinder block on a special stand. To do this, by plugging the holes in the cooling jacket of the cylinder block, water at room temperature is injected into it at a pressure of 3 kgf / cm2. No water leakage should be observed within 2 minutes.
If oil gets into the coolant, then without complete disassembly of the engine, they check for cracks in the cylinder block in the areas of the oil channels. To do this, drain the coolant from the engine 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, which is located near the first cylinder head bolt (see fig. 13, a). If air bubbles appear in the cooling jacket, replace the cylinder block.
Check whether the wear of the cylinders exceeds the maximum allowable - 0.15 mi. The cylinder diameter is measured with an indicator caliper in four belts at a distance of 5, 15, 45 and 80 mm from the upper plane of the cylinder block both in the longitudinal and transverse directions of the engine. To set the inside gauge to zero, caliber A.96137 is used - for engine 2101 or 67.8125.9501 - for 21011. In the area of the upper belt (at a distance of 5 mm from the top plane) Cylinders practically do not wear out. Therefore, by the difference in measurements in the upper and other belts, one can judge the wear of the cylinders.
If the maximum wear of the cylinders exceeds 0.15 mm, then the cylinders are bored to the nearest repair size of the pistons (enlarged by 0.4 or 0.8 mm), leaving an allowance of 0.03 mm for the honing diameter. Then the cylinders are honed, maintaining such a diameter that when installing the selected repair piston, the gap between it and the cylinder is 0.05-0.07 mm for 2101 engines and 0.06-0.08 mm for 21011 engines.
There may be deformations on the plane of the connector of the cylinder block with the head, so the plane of the connector is checked using a ruler and a set of probes. The ruler is installed along the diagonals of the plane and in the middle in the longitudinal direction and across. If the flatness exceeds 0.1 mm, the cylinder block is replaced.