Radiator Caps

As a crucial part of the cooling system, a radiator cap ensures the proper amount of pressure is held whilst the vehicle is running. With the cooling system designed to move heat away from the engine, a pressurised system is important and vital to ensure the boiling point is increased whilst the engine is running.

Driving without a radiator cap is not recommended, as your cooling system requires fluid to be able to function correctly. Driving without a radiator cap allows the water to escape out the top of your radiator. Driving your vehicle for long periods of time without a radiator cap and having low coolant levels can cause other problems, such as overheating, blowing a head gasket or causing irreversible damage to your engine.

Like with most components on a vehicle, a radiator cap will have a limited lifespan, and when it comes time to replace, you may notice a number of different signs indicating replacement being imminent, these include:

• Overheating - Whilst not exclusive to a faulty radiator cap, overheating can be caused by a variety of different reasons. If your radiator cap is not sealing properly, your cooling system cannot pressurise properly, therefore, it cannot move enough heat away from the engine. If you notice your temperature gauge rising or higher than usual, it is worthwhile to work out the cause of the overheating.
• Overflowing coolant reservoir or overflow bottle - A coolant overflow bottle is designed to catch any overflow coolant from the system. However, if the system isn't performing correctly, an excess amount of coolant can fill the reservoir and can also overflow the reservoir tank. This can occur due to excess pressure caused by the radiator cap not working correctly.
• Steam coming from the cooling system - this can be caused by a bad seal from the radiator cap. If your engine is steaming, this is an indication that the coolant is boiling and is escaping through the bad seal. If you notice this, you need to look at getting a replacement radiator cap as soon as possible.
• Air within the cooling system - when your cooling system is not sealing properly or the radiator cap is broken, this can allow air into the system. This creates air pockets that can go into the radiator hoses, thermostat, and heater core. If you get these air pockets within your system, this can cause your engine to overheat, as your cooling system cannot keep a consistent temperature.