no heat, but heater core is good
 

Hey I have a 2002 blazer that does not have heat. I checked to core and it is not leaking. I ran a garden hose through it so I know it is not clogged. The truck heard up 180 or so but still no heat.

maybe you blend doors aren't working? the other options are blown head gaskets.. are you losing water?

I doubt its a head gasket....COULD be...but not having heat is probably another issue..


Is your blower fan working? Is the air blowing at all?

I have plenty of water, and the fan is working. when I cut on the heat I get 50 degree air, and when I move the temperature control to cold I get 40 degree air. so I think the temperature control knob is working as well.

How do I check the blend doors?

im having same problem. exact!!!! no head gasket issue, no loss of water,fan blows with no problems. after 15 min or so i start to feel very little heat. heats up to 180-200 range.

is it a thermostat?

mine is also a 2002

Might be the switch in the dash is faulty.

your bend door might be stuck open

and its letting the cold air in

I would think it is not the blend doors cause when I move the temp knob to cold it does get colder a little. Maybe the doors are moving but not shuting. How do I check the blend doors and what knob moved the blend doors, the temp knob?

how do I make sure if it is the blend door or not? I just checked the water again and it is fine. I have no clue what to do next.

Any clues?