What is a radiator cap pressure test?
A radiator cap pressure test is a diagnostic procedure to check the functionality and integrity of a car’s radiator cap and cooling system.
Automotive cooling systems prevent overheating by cycling coolant through the engine block and cylinder head. The coolant absorbs heat from the engine and sheds that heat in the radiator. The system requires a certain amount of pressure to increase the coolant’s boing point, boosting its ability to protect the engine from damage.
The radiator cap is responsible for regulating the pressure in the system—it has a specified pressure rating and will not allow the pressure to fall too low or rise too high when working correctly. If the cap fails, the entire system may develop problems and fail to cool your engine. A radiator cap pressure test uses a special tool to observe whether the cap can maintain the specified pressure.
When should I pressure test the radiator cap on my car?
There is no set testing interval for radiator caps. But some signs point to potential issues with the cap. These are the most common signs that you should pressure test your radiator cap:
Coolant leaks: If your car is leaking coolant, it could be a sign that your radiator cap is faulty.
Overflowing coolant reservoir: If the cooling system pressure gets too high due to a faulty cap, the reservoir may overflow to relieve the pressure.
Collapsing or exploding radiator hoses: If the pressure falls too low or grows too high, the radiator hoses may collapse due to the vacuum or explode due to excess pressure.
Engine overheating: If your car is leaking coolant or has air in the cooling system due to a faulty cap, the engine is likely to overheat.
Keep in mind: These issues can indicate other problems with the cooling system, like a faulty thermostat or a bad water pump. It’s always wise to visit a mechanic for a proper diagnosis.
How often should I pressure test my radiator cap?
There is no universal interval for pressure testing car radiator caps. Your manufacturer may include this information in the recommended maintenance section of your owner’s manual
. But, most of the time, you don’t need to pressure-test your radiator cap unless you see signs of cooling system problems, like coolant leaks or engine overheating. Can I pressure test my radiator cap myself?
A radiator cap pressure test can make an excellent DIY project. It’s a relatively entry-level job and even novices should be able to complete it with the right guidance.
That said, if you’re uncomfortable handling coolant or dealing with the cooling system, you should contact a professional mechanic.