Heater not heating

[pacoco]

I have a '91 Ranger. Lately, the heater is not always putting out any
heat. Blower works fine. Could it be the thermostat getting "sticky" ??
Since sometimes it does work........ Thanks......

 

[MrShorty]

I could be the thermostat sticking open, it could also be the heater core is clogged, or something else. Does your engine warm up as indicated by the dash gauge?

 

[MadMike6786]

i have the same problem. i replaced the termostate but i didnt fix the problem. go ahead and try it cuz it might work. theres a door that moves from the heat position to cold. urs is probably stuck in between. i had to play with the switches to get it to stay in the heat position. its not worth getting fix unless ur rich someones told me it would cost around $800 becuase they have to remove the dash and other stuff. i have a web site ill have 2 show u that this one guy did to fix his problem that im gonna try

 

[pacoco]

I could be the thermostat sticking open, it could also be the heater core is clogged, or something else. Does your engine warm up as indicated by the dash gauge?

Temp gage does show engine is warming up. Actually, the gage does show engine getting hotter than it used to, come to think of it... If the thermostat stays partially closed.... does that cut flow off to heater core ? I looked, there are no flow control valves on either heater hose. Dash controls all look to be simple cable type.... Puzzling thing is that it sometimes works !! ??
Thanks..

 

[MrShorty]

Correct, there are no flow controls on the heater valves for a '91. And the thermostat shouldn't effect flow through the heater core either. Basically, if the water pump is pumping, there should be flow through the heater core unless the heater core is clogged, unless there isn't enough coolant for the water pump to pump. Coolant level ok? I expect your heater core is clogged, and, from the other stuff you said, maybe the whole cooling system (we are talking about a 15 year old vehicle). If it's been a while since it was last done, it might be time for a good cooling system flush, inspection, and fill.

 

[Fred02X]

I had an 89 Bronco II that had that problem, one of the hoses was plugged.....I'd say check the hoses and the heater core like MrShorty said.