What are the reasons for the reverse flow in the Nissan Livina auxiliary water tank?
2 Answers
The reasons for the reverse flow in the Nissan Livina auxiliary water tank include cylinder block having sand holes or cracks, and blockage in the return water (air) pipe. Cylinder block having sand holes or cracks: The main cause of this phenomenon is a blown cylinder head gasket (wet cylinder liner) or large sand holes or cracks in the cylinder liner or cylinder head. This occurs because, during engine operation, the pressure of the compressed air or combustion gases in the cylinder is greater than the pressure of the coolant in the cooling passages. These gases are forced into the engine's cooling passages through the damaged cylinder head gasket or large sand holes or cracks in the cylinder liner or cylinder head. This forces the coolant in the engine's cooling passages to spray (or overflow) out from the radiator (expansion tank) filler opening. Additionally, this fault may also lead to difficulties in starting the engine or failure to start, engine shaking, reduced power, water spraying from the exhaust pipe, or white smoke emission. Blockage in the return water (air) pipe: The return water (air) pipe from the upper water chamber of the radiator or the upper part of the thermostat to the expansion tank is blocked or not clear. This happens because when the accelerator is pressed and the engine runs at high speed, the water pump operates at high RPM. At this time, the pressure of the coolant in the engine block, cylinder head, main water outlet pipe, and upper water chamber of the radiator is very high, while the coolant in the radiator cooling tubes, lower water chamber of the radiator, and water pump inlet pipe is in a negative pressure state. The coolant in the radiator cooling tubes moves rapidly towards the lower water chamber.
I've encountered the issue of coolant overflow in the Nissan Livina's overflow tank several times, and there are quite a few common causes. The most frequent culprit is a damaged cylinder head gasket, which allows high-temperature gases from the engine cylinder to mix into the cooling system, increasing pressure and causing the fluid to expand and overflow. It could also be due to a poorly sealed radiator cap, where the pressure valve inside the cap malfunctions, causing the coolant to spray out when the engine is hot. System blockages, such as clogged hoses or radiators with debris, can lead to poor circulation, causing the fluid to overheat and expand. Engine overheating itself can also trigger coolant overflow, such as from a faulty fan or a stuck thermostat. If you notice the temperature gauge suddenly spiking, stop driving immediately to avoid engine damage. It's best to have a professional shop perform a pressure test to diagnose the issue, and regularly changing the coolant can help prevent similar problems.
