i just did my thermostat because the dang truck had no heat and now i ran the thing and it still has no heat? could this be the water pump? is it a hard job?

 

Naaa! Wouldnt be the warter pump. My guess would be the Heater Core. Sorry i dont have much knowledge repairing the Problamo....

 

Might be a simple as a stripped temperature control ****.

You need to do some diagnostic work before you pick up another wrench.

Steve

 

Do both heater hoses feel hot? If they do you might have a problem with the blend door inside.

 

Make sure you have bled all the air out of the system.

 

After you have eliminated the simple & obvious,search on blend door problems. It's a gotcha problem.

 

what is it and where is it? never heard this one before???

 

Do a search on blend doors. You will get plenty of information on how to diagnose the problem and what is involved in the repair.

 

I have the same problem on the same vehicle. Could both blend doors for the front and rear go out at the same time? I havn't checked the blend doors because both the front and rear heat doesn't work (switches and motors work). The upper radiator hose will not get hot. I've pressure tested the system, checked the fan clutch, thermostat,cap and flushed out and bled the cooling system . Both heater hoses get warm but not really hot. I'm stumped

 

f2504x4man, I had same problem last winter 2008...2000 Expy no heat front or back. I changed thermostat, flushed heater core and it started putting out warm heat enough to get thru winter. Now 2009, it's back to original state...no heat front/back. I'm thinking of changing water pump.

Did you figure out your problem?
Thanks.

 

If your water pump was bad you'd have a lot more problems. Given what you've done in the past, I'd say your heater cores are plugged again. Once these plug off a flush may only give you a temporary fix before they plug up again like you're seeing. I think you'd be throwing your money away on a pump and still be stuck with the same problem.

 

a few thoughts, upper rad hose should get hot if it doesn't you prob have an open tstat. feel both heater hoses at the firewall if they are both hot your core is prob fine. you can go to heatertreater.net and learn all about the blenddoor. some of these motors have heater control valves that are inline with the heater hoses, they can leak and or go bad. I would only use motorcraft tstat. In theary the fins can break off the waterpump dimishing the coolant flow but as posted earlier you prob would have had others issue like overheating in the summer. IT IS VERY IMPORTANT TO GET ALL THE AIR OUT OF THE SYSTEM AFTER CHANGING TSTATS ETD,. AIR BUBBLES CAN CAUSE A LACK OF HEAT