Common Symptoms of a Bad Radiator Cap

Here’s an important safety tip –never open the radiator when the engine is hot because a bad radiator can cause excess pressure to build up in the cooling system if you open it. At the same time, it is still hot that pressure can release suddenly causing hot coolant to gush out and potentially burn you. Now that we know what the radiator cap does, let’s check out what are the common symptoms of a bad radiator cap.

Coolant Leaking

If your radiator cap is faulty you might notice frequent coolant leaking specifically from the cap itself. So with the car running pop the hood and take a look at the radiator cap and if you see coolant- check for keeping out that is a sign. It’s time for a new radiator cap but in the worst situations, coolant can escape from other areas like the radiator hose, the water pump, or an engine gasket. This happens because if the cap is stuck closed it won’t allow the coolant to flow into the reservoir when pressure is applied. That pressure has to go somewhere so it forces the coolant out through other weak points in the system.

Engine Overheat

A faulty radiator cap can mess with the pressure in your cooling system which can lead to air pockets forming when there’s air in the system instead of the coolant. In this case, heat does not get absorbed properly and that can cause your engine to overheat on top of that if the cap is not holding the right pressure. The boiling point of the coolant drops this means the coolant can start boiling sooner than it should making it less effective at cooling the engine.

Collapsed Hose

Next up is collapsed hose, if you have noticed that your radiator hose looks like it has been sucked in your radiator cap, it might be the culprit. Here’s why when the engine cools down. A vacuum forms in the cooling system to pull coolant back from the reservoir, if the radiator cap isn’t working properly and can’t release that vacuum the pressure difference in the radiator can collapse inward.