I seem to have a heating problem in my 93 F150. The problem is: Little to no heat coming out of any dash settings with the heater control on full hot. Even with the truck on for hours running around town or idleing, the heat coming out of the heater is barely enough to notice.
Recently, within weeks, changed the water pump and thermostat. Put in a 190 degree thermostat but I think the old one was a 210. Upper radiator hose is hot, hose coming off the thermostat to the heater core is hot, hose coming from the heater core to the water pump is cool to warm. Flushed system when water pump was replaced and put in approximately a 70/30 mixture. With engine idle for awhile, hose going to heater core from the thermostat gets HOT but return hose is warm. I'm leaning toward a new heater core, which was replaced in December of 99, anyone have any ideas??

Thanks,

Tim

 

[updated:LAST EDITED ON 08-Nov-02 AT 09:10 AM (EST)]I have changed Thermostats and it turned out that the new one was no good also.
It sounds like the new one could be stuck open.
There is also a gate valve on one of the heater hoses (The Hose that is HOT)that could not be functioning properly. Not opening up enough to let the antifreeze through the heater core. That valve is controlled by a vaccum line or a cable coming from the temperature unit in the dash.

 

The 93 F150's don't have a gate valve on the heater hose. The temperature control lever on the dash control the temperature blend door and is cable operated. There is a posibility that your cable is broken. A lot of the vehicles with Electronic Automatic Temperature Control (EATC) have trouble with the blend doors breaking. There might be a possibility that the manual system like in your truck has a broken blend door.