Pressure Cap

Cooling System

Description

The pressure cap controls pressure in the cooling system. The cap may be mounted on the radiator filler neck or on top of the coolant reservoir. That's why a pressure cap isn't always a radiator cap.

Purpose

The pressure cap controls pressure in the cooling system. The cap may be mounted on the radiator filler neck or on top of the coolant reservoir. That's why a pressure cap isn't always a radiator cap.

Maintenance Tips/Suggestions

Never remove the pressure cap from a hot engine. Doing so can cause hot coolant to spray from the cooling system, causing severe burns. The pressure cap is a critical part of the cooling system and it should be checked at least once a year. Replace the cap if bad. Any type of cooling system maintenance should include a check of the pressure cap. Symptoms of a faulty pressure cap may include overheating and a coolant reservoir that either doesn't show a rise in the coolant level with the engine warm, or a reservoir that doesn't show a drop in coolant level as the engine cools. Pressure caps vary with different applications, so don't assume that one cap is as good as the next. For best results, use the replacement cap specified for your vehicle.