Q: Heat turns cold after I drive for awhile. Got the water pump changed and the thermostat. Still having issues

If the cooling system gets low at all, usually the first thing you notice is that the heat goes away. The system could seem to be full, but have air pockets causing your problem. That can be solved by bleeding the cooling system. The procedure for that varies from car to car. Another possible cause of your problem would be if the heater core has become clogged with rust or other debris. Checking for that involves measuring the temperature of the heater hoses while the engine is running. If your car is equipped with an automatic system there could be a problem related to the automatic controls. In any case, you can have the problem taken care of at your convenience by contacting Your Mechanic. They will send a technician to your home or office to check out your heating system and let you know what it will take to fix it.