How do you flush heater core on a Pontiac grand prix?

Answer 1

2008 Grand Prix with the 3.8L. Locate the heater hoses at the engine. They are located on the passenger side next to the alternator. I wrapped a towel under the fittings to catch any spills. I also removed the coolant overflow reservoir bottle to give me a little more room for my pliers to remove the hose clamps. Do not remove the small hose to the bottle, just lay it toward the front out of the way. The top heater hose is the supply line, the bottom hose is the return. Pinch the hose clamps and slide up the hoses. Carefully wiggle the hose till it comes off the plastic fitting. Be careful not to break the plastic barb fitting, they look fragile. Coolant maybe under some pressure, so wear eye protection. I used a plastic gallon jug with the bottom cut out (screw cap still on) and placed it down in the gap between the fender and and the fittings, then placed the top hose in the jug. Get a garden hose with a sprayer and place into the lower hose. Gently spray water into the hose, don't use too much pressure. I allowed it to spill out if the pressure got too much. Watch the other hose spill liquid into the jug. If there was blockage, you will see chunks. Dispose the liquid in the jug and place the hoses back on the fittings, put clamps back in place, return the coolant bottle back to it's position, and add a little fresh coolant to the reservoir.