2009 ford ranger sport 4.0l , so went to turn the heat on today and noticed it’s blowing out cold air , no hot , blower works. What would cause this ? I’m thinking the heater core is the culprit . Is there a way to diagnose that ? Is a replacement a difficult install ? Also there is no coolant on the passenger floor. Any help would be greatly appreciated . Thanks

 

Try swapping the two heater hoses under the hood connected to the firewall. That may force a blockage back out.

 

Thank u I will swap hoses and see what happens first thing tomorrow , but in the meantime A quick update , I turned heat on again and noticed it was getting hotter then boom it went cold again . I noticed the heater hoses were hot …especially the top one . I also noticed the AC was ice cold to the touch even though the AC was not on … is that normal ? I also see a slight leak from passenger side , looks like water and not coolant , not sure where coming from . Thanks

 

Is your defroster on? That causes the AC to kick on.

 

Hmmmm possibly , I do recall going through the cycles so the defroster was probably on at some point . I’m gunna look closer tomorrow and see if there’s any leaks in the hoses etc . I also noticed there is no coolant in the overfill reservoir … so that could possibly be the problem as to why there’s no heat . I will also add the coolant tomorrow and see if it resolves itself . Thanks

 

Yes, AC is on all the time unless switch is in OFF or VENT position, its to dry the air in the cab

If both heater hoses were hot but when TEMP **** was in HOT position and cold air was coming out of vents then your Blend Door electric motor has failed
Common issue in all Fords not just Rangers

Google: 2009 ford ranger blend door actuator

Loads of videos on this repair, not really year specific, 1995 thru 2011 Rangers used the same setup
Its an electric motor and called an actuator


The Blend door routes the air from the fan/blower either thru the heater core, HOT, or around the heater core, COLD, or anywhere in between

 

Quick update , my coolant reservoir was empty , rad was low too , I added a gallon of pre mixed coolant , now the heat appears to be working again , so hopefully that was the problem . I still suspect the blend door actuator could be a problem but for now it seems to work . Thanks once again guys

 

Another update , so after adding a gallon of coolant heat started working again then 2 days later I noticed my coolant reservoir was empty again. It’s definitely got a slow leak , don’t know where , rad is not leaking , rad hoses seem fine , nothing seeping out of the water pump etc . Heater hoses are not leaking either. I still suspect that the heater core is leaking , there’s no fluid on the passenger floor area though. Sometimes I can see it leaking while idling, can’t really tell where from though. Totally stumped 🤔 . Heat still works as long as there is the correct amount of coolant in the system. Anyone else experience this ? Thanks once again

 

Are you getting white exhaust out of the tailpipe? That would indicate bad headers and you're burning it in the engine.

 

If heater core was leaking you would smell that in the cab, musty smell, and fog on inside of windshield

You can rent a Cooling System pressure tester
It is a Radiator cap with no valves, it has a pressure gauge and a hand pump attached
You fill up cold engine's radiator
Put on the cap and pump pressure up to 20psi
Wait and watch, pressure will start to drop if there is a leak
And because engine is cold you can then trace the leak back to the hole

On a warmed up engine a coolant leak can be at a spot where most, if not all, the leaking 190degF coolant evaporates before hitting the ground

 

Excellent advice thank u everyone , I’m gunna get a coolant pressure tester and give it a whirl