I have a 1999 F-150 with no heat. Air conditioner works, fan works, etc. I have a pinhole leak in the radiator and I think the previous owner took out the thermostat. The return hose on top doesn't get very hot, I can hold on to it with my bare hand. The temperature gauge in the truck runs normal. Will a new thermostat and radiator take care of this problem? Could this be the heater core or blend doors? Thanks for any help.

Travis

 

gotta start somewhere. change the thermo, change the rad, fill it with water and see if the heat works in ten min. then flush the water and or either fix some more stuff or fill it with anti-freeze

 

thanks i've got a rad. on order!

travis

 

Either one of those two problems will cause a no heat situation.

No thermostat will not let the coolant warm up enough. Pinhole leak will not allow pressure to build in system.

 

My buddy's 97 had the same issue. His was the dash temp control (it is electric not vacuum). He found if he turned a little towards the cold side it would work fine.

 

all right!!!!! i changed the rad. and the therm. no luck!!! if i turn the heat on after its warmed up,it blasts heat for maybe 30 to 40 seconds! then it goes back to blowing cold!!! heater core????

thanks to all who reply,
travis

 

put your hand on the heater hoses and see if they are hot, if they are then it sounds like the blend door mechanism

 

Sounds like your heater core is partially plugged, you may be able to clean it out by backflushing it but more than likely it will need to be replaced.

 

Hey guys, i back flushed the heater core,itseems to have helped a little.but before i change out the heater core.(i have no idea how to do!) I'd like to checked the blend doors, like beckerjs says.can some one tell me more about this and how to get to it.

thanks again guys,
travis

 

the hoses are hot

 

you pretty much have to tear down the whole dash to get to the heater core, its kinda behind and below the glove box. This is one thing, that it might be worth your time not to do it, and have a dealer take over for that job.
-Patrick

 

okay dudes, i took my truck to a mechanic and he checked out the thermostat and heater core and says everything looks good. he thinks it's the water pump. he says the water pump might not be circulating the water like it should. but my truck runs at normal temperatures and i would think that it would overheat if the water was not circulating correctly. what do you guys think?

thanks,
travis

 

I think you're right there if, it the pump wasn't circulating properly the motor would at the very least run hotter than noraml. But if it's the same temp as always then that's not the problem.

Chances are your heater core is just clogged. Backflushing is a 1 in a 100 chance, it rarely ever works. The blend valves can go bad, but that's pretty rare. Every time I've heard the heat goes out, the culprit always turns out to be the core.

I'd take it to a dealer. It's a mega pain-in-the-*** to change it yourself. Not that the actual swap is hard, it's tearing apart the whole damn dashboard to get to it. Pay a little more and save the frustration.

 

if both hoses are hot then the heater core is fine and flowing like a champ. The 97' and up Ford truck are known for blend door problems and the temp selector **** cracking, yours sounds like a blend door situation. if the heater core was plugged the flow would be really slow and the heater would blow all the heat out and the other hose would be noticeably colder if not cold. If they are both hot then the air is not blowing all the heat from the heater core. if it was plugged just remove the hoes and flush both ways with a garden hose, work most times and if it was your problem you would then need to flush the motor as well. Those flush tee's are junk and don't do a good job, they will even bypass a plugged heater core and rot out in 5-10 years many times

 

okay guys,

The problem is fixed! after going to a shop and them telling me its not the heater coer and couldnt tell me why its not hot i took it over to the dealer and they back flushed it. now the heat is great!

i guess i wasnt doing a good enough job when i tried to flush it. they still charged me $350.00 just to back flush it. they also said that if it clogged again and they needed to replace the core that they would take the $350.00 off the core replacement. so all in all if i would have taken both hoses off and done a better job or ran some cleaner threw it i might have had such a big bill in the end.

thanks every one who helped me try to figure this out.
and i hope someone reads this and it helps them out!


travis