When your car temperature is starting to be abnormal, you might wonder about radiator cap function and bad symptoms in the car. The radiator cap is often considered as insignificant. So people and mechanics tend to underestimate some signs and symptoms of a broken or wear out radiator cap. As car owner, taking care and paying attention to the radiator cap is important.
Radiator Cap Function
As the name implies the radiator cap function to cover the radiator. It helps the radiator coolant to stay in their place. It also prevents foreign object to get into the radiator. A foreign object like gravel could damage and clog the radiator system. Radiator cap also maintains the coolant in a high pressure, therefore the boiling point of the coolant is increasing. But the function is more important than just to cover the filler. It also works to maintain the pressure of the radiator in the operational range and to stream the radiator into the reservoir.
The radiator cap plays an important role in the engine cooling system. It maintains the coolant circulation to happen in the engine, either in the cold condition or hot condition. So the engine temperature could run in the operational range temperature. When the coolant is heating up, the coolant expands and the radiator becomes highly pressurized. The radiator cap acts as a release valve to let the pressure go at a certain pressure. When the pressure is reaching the rated pressure, the valve will be open, letting the coolant flow into the expansion tanks. Then, after the radiator is cooled down, the coolant will be sucked up by the vacuum back into the radiator.
The radiator cap consists of several parts. The filling neck provides a solid thread where the radiator cap is sitting on. The filling neck is also has a hose to the reservoir. So when the valve on the radiator cap open, it will flow into the expansion tanks. The radiator cap consists of two valves, one is the pressure valve and the second one is the vacuum valve. The pressure valve opens when the radiator is in high pressure. This condition happens when the engine is hot condition. While the vacuum valve open after the engine is cooling down. It sucks back the coolant in the expansion tanks back into the radiator.
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Bad Radiator Cap Symptoms
So, now it’s clear that the radiator cap is a significant part of a cooling system of a car. So, when there’s issue in the cooling system, it’s better to check the radiator cap function and bad symptoms in the car. Here are signs of a broken radiator cap.
1) Leaking Coolant
If the coolant is leaking, the radiator car could be broken or not working properly. The leaking coolant is a sign that the radiator cap keeps the pressure build-up to rise higher than it should. Then, some parts that could not withstand the pressure starts to leak out the coolant to release the pressure.
2) Overflowing Reservoir
If the reservoir or the expansion tanks contains coolant that exceeds its limit, even in the cold condition, the radiator cap could be the culprit. It could happen because the vacuum valve failed to open. So, the radiator keeps channel out the coolant when the car is hot, but when the car is cooling down, the coolant doesn’t flow back into the radiator.
3) Radiator Hose Collapses
Same as the leaking coolant, if the radiator cap failed to release the pressure, it could pressurize the hose and force it to collapse. The hose could also collapse because of the vacuum that ceased by the vacuum valve failure. The negative pressure squeezes the hose so it gets collapsed.
4) The air in the radiator system
If there’s air in the radiator system, the radiator cap might not seal properly. The air in the radiator could reduce the heat transferring ability of a radiator. Air in the radiator should be dumped out to avoid overheating.
If these problems ever happen, you might try to change the radiator cap. Knowing the radiator cap function and bad symptoms in the car could help your car stay in the best performance.