#3. 6.6 LITER DIESEL. Lower. PartQualifier: #3. Return hose. A line that carries coolant from the engine through the turbocharger and back into the engine. Hoses carries permanent coolant, or antifreeze, throughout the engine, heater, and radiator. Intercooler Hose. Line used to transmit oil amongst the turbo, Intercooler and engine. Charge Air Cooler. Engine Coolant. Intercooler. Oil outlet. Pipe. Pressure. Turbocharger Oil Line. Water feed.