No Heat!!!

[redneck pimpin]

Hey guys, I have a 1995 Reg Cab, long box, with a 4.3 V6 as my winter rat. Well I got it for a 150 bucks three yrs ago. i have put tires on it thats it!! 184k on it. Anyways Its never had really good heat and I have been trying to fix it. I have replaced the thermo-stat, Heater core, blower motor resitor, It has great heat just sitting in the driveway at idle. Once I start driving it and get over 50mph all i get coming threw is the cold outside air?? Any ideas? Truck also runs like 185ish for temp?

[redneck pimpin]

K i have changed the water pump, heater core, thermostat. I have heat at idle but once i start driving it the hot air cools roght off until i stop again. The flapper inside the heater box works fine also. Coolant level is full. I did notice that the heater line from the back of the motor that goes to the heater core is alot hotter than the one coming from the water pump? is that normal?

[oleshifty]

sounds like a heater control valve...or your manual clutch fan is locked and is pulling TOO much air

with motor off (and cool) the fan should almost free spin...if its hard to turn the clutch is stuck engaged



if not, the heater control valve is probably not circulating

[straightaxle]

those trucks don't have heater control valves. my guess is the blend door is pushing itself into the cool position

[GasGuzzler]

+1 on heater control valve.

^^^ +1 in relation to post above (definition of +1 leading to post directly above)

[straightaxle]

alldata says no heater valve

[GasGuzzler]

I thought we already estabished it had no valve. My head says no valve either as posted above.