99 Envoy heating problems

I've replaced the heater core, radiator, hoses, thermostat and water pump. And I still don't have heat! I have semi warm air blowing out the vents. If I put the defrost or floor on it's all cold! Does anyone out there have any suggestions?

Where does your temperature gauge read?

Check to see if both the heater hoses get hot. If only one gets hot
you have a flow problem. If both get hot, you most likely have a blend dorr problem.

Where does your temperature gauge read?

Check to see if both the heater hoses get hot. If only one gets hot
you have a flow problem. If both get hot, you most likely have a blend dorr problem.


Ok! Thanx! I'll check with my husband to see if he did that! It's getting really cold around here to not have any heat!!

If only one is hot it indicates that the coolant isn't flowing freely through the core, some trash could have plugged it (possibly something knocked loose or introduced during the replacement of some of the other componets) or there may be an air bubble in the core (generally noticed by a slushing/gurgling sound in the dash). If both are hot, most likely the blend door isn't operating, which could be a problem with it or the controls. Just report back whatever you find out and we'll go from there.

its possible you have a little air in the heater core. I had this problem with my sons 2000 s10 blazer.
With the motor cool, and the vehicle facing slightly up hill remove the radiator cap, start the motor and run until warmed up. I put a small screwdriver against the throttle linkage to raise the idle to 1000 rpm. If there is air in the system once the water starts to circulate through the radiator you will see bubbles and the level will drop slightly. Mine ran for 30 minutes after warm up and the heat is now very hot.
good luck