The hoses should not be put on the connecting nipples too short. Check the tightness of the hoses and the tightening of the clamps. Replace the clamps if necessary.
Check the fuel tank cap gasket for damage.
Caution: A low coolant level may be caused by an incorrectly tightened cap.
If the coolant level drops quickly and no leaks are found, check the cooling system on a warm engine. If coolant flows out of the hole in the lower part of the water pump on a hot engine, the pump shaft seal is faulty. In this case, replace the water pump.
Noticeable loss of coolant and/or the presence of engine oil in the coolant, as well as white exhaust gases on a warm engine indicate damage to the cylinder head gasket.