Quick Question for ya'll. 2005 Siverado 4.3L has no heat. I have been told it is most likely the heater core but is there anything else that could cause it? Looking for an easier way out. The fan blows in all speeds and the AC works fine. Thanks for any input.

 

maybe the engine isnt producing any heat? lol bad joke im sorry...

 

Well it is a small engine

 

I have done a lot of intake gaskets on the 4.3l. External coolant leak. If coolant is low enough you wont have heat. Check the level of coolant first. If it is full check the temp of your heater hoses to the heater core at the firewall. They both should be the same as upper radiator hose temp. If the upper hose isn't that hot the thermostat might need to be replaced. Back to the heater hoses. If one is hot and one is cold heater core is plugged. If so disconnect the hoses from the heater core and backflush with a garden hose both directions. Had this work many times. If hoses are hot to the core and still no heat time to look at temp doors inside the vehicle. Possible actuator.