Howdy all! Heres the story. Bought a used f-150, drove it home(4 hrs) Overheated 2 times,(no heat), added anti-freeze, nursed it home, changed thermo. still no heat! Eventually got heat flowing, never overheated again! 6000 km later, getting cooler outside, tried heater, guess what! No heat! Just got it back from the shop, they replaced the control switch (dash), as they were tested,and found faulty. Still no heat! They also say that the hoses goin to heater core are hot (top rad hose?) But the hoses coming out?? are cold?? WHAT NEXT!!!! Huntin season is almost here, I NEED HEAT!
PS - Could a heater core be plugged?
Thanx!!

 

It's possible the core is plugged as it's a used vehicle and you have no idea how the previous owner looked after the cooling and hvac systems. Check for a 50/50 mixture -35*F? Pure anti-freeze won't conduct heat well.
It could also be air locked. Try turning heater control to heat with fan on hi. With engine at operating temp and reving near 1500-2000 rpm pinch the hot heater hose and then release a few times. This might force air from the core.

So why did the shop that charged you for a heater control switch tell you the hoses don't have equal temps as they should and then leave you hanging?

 

If you suspect a plugged heater core,(and you can get to both hose connections) drain the cooling system,and disconnect the core. Hook a scrap piece of hose to the core,and run a water hose to one end.The other end should flow relatively un-restricted.If it doesent,you indeed have a plugged core.

 

I suspect the shop I used might be a little shakey!!??

 

Kinda sounds like it,'Usually" a restricted heater core is fairly easy to diagnose.But whatever you do,its a must to confirm it before ripping the inside of the truck apart....

 

I will try to download a manual, or some instruction as to how the hoses get dis-connected from the heater core. Any info on that? I'm new here, and don't really know my way around yet.
Thanx again to all helping, really appreciated! Always looking to save a buck and try fixin things myself.

 

Wish I could help further,but without being there wouldnt want to guess....Good luck,and Welcome to the forum