The hoses must be put on the connecting pipes all the way. Check the reliability of the hose fastening with clamps, replace the clamps if necessary.
Check the expansion tank cap seal for damage.
Caution: Too low a coolant level in the cooling system may be the result of a poorly or incorrectly tightened cap.
If the coolant level drops frequently and the leaks cannot be localized, it is necessary to check the system with the engine warmed up. If the coolant flows from the hole in the lower part of the pump with the engine warmed up, then, as a rule, there is a defect in the pump shaft seal. In this case, the coolant pump must be replaced.
Obvious loss of coolant and/or the presence of oil in the coolant with white exhaust gases on a warm engine indicate a defective cylinder head gasket.
Note: Sometimes it is very difficult to locate the leak. In this case, it is recommended to pressure test the cooling system in a workshop (a special device is required). At the same time, you can check the excess pressure valve in the expansion tank cap.