GM Genuine Parts Engine Coolant Bleed Hoses are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These hoses are used to release (bleed) trapped air in the cooling system. They help prevent loss of coolant circulation and reduces the chance of your vehicle's engine overheating. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).