I am having major heater issues. I have put in a new thermostat, new water pump, flushed the hoses and back flushed, checked the actuator door, and had heater coils checked, they were ok....so why don't I have hot air???...can anyone help me out here...cold weather coming, and I need some HEAT!!!....

 

I was about to start the same topic. I haven't replaced anything yet, but I've flushed the system. when my thermostat kicks in they're is a low groan and then a click. can anyone give us some help.

 

oh its a 2002 f150 super crew with a 4.6.

 

First see that the gauge is running at normal temp- that means the thermostat is o.k... Next feel the heater hoses into and out of the heater. That will give you an idea of the max temp you can transfer... Next make sure the radiator and overflow tank are full to the mark. If you are 1 quart low, you will get a air pocket in top of the heater and will not get it out. Trapped air means no heat. If the hoses are hot, see if the dial **** on the dash is o.k. or slipping. You can pull it off and see if it is tight on the shaft or slipping. If it is movning, you then need to see if the blend door is working and closing off the cold air. The door is under the radio, above the transmission hump. With the plastic panels off, you can see the motor and probably the crank and arm. See if it is stroking and moving the door when you move the lever is moved. Last resort, you can have a heater that is half full of crap. You still get flow thru half of it, but not enought surface area to transfer much heat. You might get like 80 degrees out of it on a cool day. Is the air ALWAYS cold, never get hot spikes or change in temp when you move the **** ?

 

You can also check your antifreeze for 50/50 mix. It should be good for -35f--40f. If it's pure or too high a freeze temp rating the coolant may give poor heat transfer through the heater core.

 

does it have a vacuum operated heater core by-pass valve? if soo, checck to see if thats workin....

 

The heater on my 2001 f150-215,000 miles has been sporatic.Not really hot........I could hear the blend door moving from cold to hot. I changed the thermostat. no change. Then I removed the hoses to the heater core and with a small orifice nozzle attached to my garden hose I blew out the heater core. I alternated between inlet & outlet. I did indeed see junk come out & then clear water. Re-connected & now my 215,000 mile F150 has a heater like new!!

 

I had a 99 Taurus with a plugged up heater core. I disconnected the supply and return hose, plugged the return line and filled the supply line with draino plumbing cleaner. I left it in for about 20 minutes then flushed it out really good with a hose. Back yard idea but it worked like a champ for me.

 

Way to go CC. Better than spending 800 to replace the heater core(the dash would have to be removed!). Regards from San Jose,Calif.

 

can you tell me where that's located?

 

follow the heater hoses, if you dont see a diaphragm with a small tube stikin out of it, you dont have one. but if you do, make sure it works, if it doesnt move when select heat, check to see if its getting vacuum. if not, look for a vacuum leak.