Pressure caps are a vital part of the cooling system of a vehicle as they seal the opening used to add water to the radiator. The liquid in the Auto radiator assists in preventing the vehicle's engine temperature from getting too hot or too cold. When the engine is running, the temperature of the liquid increased and the liquid starts to inflate, causing an increase in pressure in the automotive radiator. Most radiator pressure caps are designed to not only provide a watertight seal but also to act as a valve to release the pressure. If a radiator pressure cap is out of order, the consequence can be internal smash up to the engine. Cooling liquid will leak out of the automotive radiator and, as there will be a smaller amount liquid in the radiator, this could result in overheating troubles.