Heat problem in 2006 Pontiac Gran Prix - can it be a water pump, or heater core?

Go on U-tube and you can find several individuals that have videos that show step by step on how to change the heater core on your or any vehicle.

when you have that problem , almost all the time is the heater core clogged , you can have the engine running until reach normal temperature and touch both heater hoses at the fire wall, if one is hot and the other is not them the problen is your heater core.

heat control valve shut off.

Check the operation of the heater control valve. It will be conected to one of the smaller hoses leading to the heater core from the engine.

have your thermostate checked.

Ok fellow 2006 Grand Prix owners!! By trial and error, I went through the process of elimination because my car would over heat and had no heat inside. After changing the thermostat, I had to replace the water pump. However, after you do this, you need to open the inlet hose bleeder and let the air out a few times. This solved my issue of overheating and I now have great heat!!!

If leaking coolant under dash on passenger side floor broad it's your heater core. Call's for 2.8 labor flat time to remove heater core, in some case's you'll have to recover, evacuate and recharge your A/C system to remove your heater core.Sit under dash on passenger side.

Are you sure you got all the air out of the cooling system? Air pockets are very common problem when you do any work to the cooling system. An air pocket will do what you discribe.

There is a flat filter that sits between the firewall and the blower. Sometimes the filter is blocked and needs to be cleaned or changed. On older cars the filter is located on the firewall in the engine compartment infront of the blower. In the newer cars the filter is under the dash inside the car and much harder to get too.,

i do believe you have to take the passengers side dash apart behind the glove compartment. go to autozone and get a manual or go to the library and check the chiltons manual. this is not an easy job. how bad is the leak? if its not bad these heater cores are made of all aluminum. i would buy a bottle of that radiator additive and see if that takes care of the problem first. it only cost about 5 bucks a bottle and it may permanantly fix your problem.