GM 88956887 Core Asm,Heater

Safety requires you to disconnect the battery cable from the negative terminal after disabling the Theftlock audio system lockout and before the battery removal. Position the vehicle's front section upward and set jackstands under it to secure it in stability while engaging the parking brake and blocking the rear wheels against wheel movement. Before commencing drain the cooling system solution and extract the drain hose from underneath the heater case. The first step inside the passenger area requires panel removal from under the dash along with steering column trim covers and floor console when present. Beginning with the heater outlet duct and glove box allows access to the heater core cover. The heater core hoses require removal but exist for accessibility through the firewall opening inside the engine compartment. Engine rotation forward may be needed for 3100 units but the 3.4 liter requires complete plenum removal and removal of fuel lines along with exhaust crossover pipe and transmission dipstick tube. All heater pipes that are not an integral part of the core need metal clip removal at core entry points before twisting and pulling pipes out to extract the heater core by its upper and lower edges. Place several old towels on the floor next to the damaged space to prevent carpet stains from leaking coolant. The cooling system refilling takes place after heater core installation which follows removal steps.