A blown head gasket is one of the many things that can cause this issue. When the engine is running, the compression from the cylinders can leak into the coolant passages, causing air to be trapped and compressed in the cooling system. This can cause air bubbles to form in the coolant tank.
2. Faulty thermostat
A faulty thermostat can also cause air bubbles to form in the coolant tank. When the thermostat is stuck in the closed position, it can block the flow of coolant, causing the engine to overheat. This can cause steam bubbles to form in the cooling system, which can then turn into air bubbles.
3. Incorrect coolant level
If the coolant level is too low, it can cause air bubbles to form in the coolant tank. This is because there will be more room for air to enter the system when the coolant level is low.
4. Damaged coolant hoses
Damaged coolant hoses can also cause air bubbles to form in the coolant tank. This is because coolant can leak out of the damaged hoses, allowing air to enter the system.
5. Faulty water pump
A faulty water pump can also cause air bubbles to form in the coolant tank. This is because the water pump is responsible for circulating coolant throughout the engine. If the water pump is not working properly, it can cause the coolant to overheat, which can lead to the formation of steam bubbles. These steam bubbles can then turn into air bubbles.
