Symptoms of a Bad Radiator Cap

An internal Combustion engine generates a lot of heat in normal working and it becomes necessary to exhaust heat to avoid any serious issue which further leads to engine failure.

The most common cause of the cooling system failure is the bad radiator cap which leaves you stranded in the middle of the road if you are on a long journey, and it can even lead to the total engine failure. It is very easy to replace the radiator cap when you know the signs, indicating a fault in the radiator cap.

How Does a Radiator Cap Work?

The cooling system works at high pressure to exhaust heat from the engine, that’s why the radiator cap is also known as the gatekeeper of the cooling system. Each cooling system works at different pressure according to the requirement of the vehicle, companies install different capacities of cooling system like if the engine is more than 2.5L then the cooling system works at high pressure their strong radiator cap is used to sustain liquid in the cooling system.

Each radiator cap is rated with a certain amount of the pressure which it can bear therefore it is very important to purchase a radiator cap which is recommended by the vehicle manufacturers.

The cooling system of the vehicle works at high pressure because, by the increasing pressure of the coolant, it enables the coolant to absorb more heat as compared to the normal condition. Mostly every engine of the vehicle works around 100 centigrade which is the boiling point of the water.

If the coolant already at boiling point in the normal operation of engines then it will not cool down the engine effectively, by increasing the pressure of the coolant makes the engine run smoothly and more efficiently in harsh environments and protect it from serious damage.

Coolant is the combination of antifreeze agents and water which consists of one to one ratio. The water helps to absorb heat from the engine and antifreeze increases the boiling point of the coolant.

Coolant evaporation is unfavorable because gaseous coolant takes more space and it over pressurizes the cooling system in harsh condition like in summer where the temperature of the external environment is very high or if there is any tiny hole in the radiator then it can escape through it and reduce the level of the coolant which can cause overheating of the engine.

To avoid the overpressure in the cooling system, which can cause serious damage to other components of the system. The radiator cap is equipped with a spring-loaded valve which removes excess coolant gas to reduce the pressure in the cooling system.

Common Symptoms/Signs of a Bad Radiator Cap:

Faulty radiator cap can also be a sign of other issues like head gasket failure. Therefore if you find an issue with your head gasket then it is not a good idea to replace the first radiator cap which is cheap and easy to change, you need to address expensive problems if you don’t repair in time which can lead to the total engine failure.

1- Coolant Leak:

If you try you use a radiator cap that holds more pressure than the system is designed for, then it can cause a leak in the radiator. If the radiator cap unable to reduce extra pressure to release when the cooling system reaches the target pressure. It is a natural law that substances always flow towards the least resistance therefore the coolant will leak from the weakest point if the cooling system is over-pressurized.

The leak can occur in the radiator, gaskets, water pump, or hoses. It is very easy to determine leak by increasing the pressure in the system by heating up the engine, you can carefully look for the coolant leaks. Different types of vehicles use coolant of various types. You can differentiate them by colors; it can be blue, bright green, red, orange, or yellow.

Sometimes leak in the cooling system appears when the vehicle reaches at operating temperature or after driving the vehicle for a few minutes. You might notice a leak from the pipe directly to the air or into the engine bay.

To find the exact location of the leak, wait until the engine of the vehicle cools down and then pinched the pipe suspected area, if you find that coolant is leaking from the hose then it is very important to replace with the new one because it reduces the level of coolant in the radiator which can further cause overheating of the engine. Hoses are very cheap and easy to replace but make sure to bleed air in the pipe to avoid overheating the engine.

2- Overheating of Engine:

Bad radiator cap or head gasket causes insufficient seal as a result of pressure leaks from the radiator and can cause an engine to overheat. Because decrease pressure of coolant means low boiling point which makes decreases the heat-absorbing capacity of the coolant and it turns the coolant into gas and coolant gives poor performance. When this happens you will notice a rise in temperature on the gauge of the infotainment system.

If you ever fell in this situation stop your vehicle immediately and wait until your vehicle engine cools down before continuing your journey, you can also call a tow truck if the condition goes serious and the vehicle engine failed to start. If you didn’t stop the vehicle in time and continue driving while ignoring the high-temperature warning then your vehicle engine will eventually overheat and moving parts within the engine start to meltdown and cause total engine failure.

3- Steam From the Engine:

 As I mentioned above when your vehicle starts overheating due to the coolant leak, it evaporates the coolant which resembles steam. If you saw steam coming from your engine bonnet its means that your coolant is boiling and turning into steam and escapes from the defective radiator cap or a hole in the hose, immediately stop your vehicle and try to fix this issue if possible before starting your journey again.