so my heater is blowing out hot air when the truck is moving, but lately when I come to a stop sign or a red light it starts to blow cold air. Then when I start moving again it comes out warm again...

am I low on antifreeze? or something else?

thanks

BOB

 

What year, model, and type of climate control system?

 

I was thinking it wouldn't matter, but 2011 ford F-150 4x4 XLT....

as far as I know they only offered one heating system....so what ever came with the truck.

has sync, stereo, cd


bucket seats......

bob

 

Is it manual or automatic temperature control? Single zone or dual zone?

 

its manually controlled...NO thermostat!.... zone>>> id guess single zone....my vette has a separate controls for the passenger, if that's what your talking about...then its single control....


thanks

bob

 

ok so what was the purpose of all the questions???????????

 

So someone who knows what they are talking about can properly advise you. Different systems work differently.

Whenever making a post for assistance, the more details you provide, the better help you will get.

 

What does your temperature gauge show??????????

It sounds like your engine may be cooling off too much when you're not moving and the engine coolant isn't hot and therefor the heater isn't heating.

You could be low on coolant and it isn't pumping enough unless the engine is running at highway speed. I have seen cars that acted that way but I've never run my F150 low on coolant so I'm not sure how it would act. Haven't you checked that? It's an EASY check.

How long are you driving at one stretch? I used to live in northern Vermont and I had to drive an HOUR before the heater in my car would start working! No fun! It turned out that part of the problem was that there wasn't enough anti-freeze in the coolant and the coolant in heater hoses would freeze and not allow coolant to reach the heater. It was TOO cold to drain the coolant so that I could replace it with a stronger mix,. Even when the engine was hot the coolant would freeze before it could all drain. I finally had to find a repair shop that would put the car INSIDE for about four hours so that ALL of the coolant could be drained and replaced.

 

well this winter its been below 0 many times and I have had heat within about 5 miles.... today the truck acted different...it was cold most of the time..wether driving or standing.. and occasionally it warmed up...no rhyme or reason..i bought some coolant and put it in and the only driving since, has been out to lunch and the heater seemed to work fine.... so ...it MIGHT have just been low coolant.... I was thinking its the rheostat on the heater door that directs hot or cold air or low coolant.... when the heat was on this morning I dialed the heat dial and it seems to cool and heat the air...so that seemed to show that dial was working......

 

I totally understand that, but some questions are ridiculous... the color of the truck and the size of the tires and the type of material inside or the length of the bed.... are all questions too!......

but I answered, and you went away for 3 days..... just seemed like a antagonist at work to me...

 

I would have answered but I'm not familiar enough with the system you have.

When asking about a heater issue, it only makes sense to provide year and model of the truck along with the details on the climate control system.

 

I am just going to put these out there,
1) Possible thermostat problem.
2) Blend door might not be opening to allow air to pass through the core. I am not sure what controls this on F150s, whether it's electrically opened or uses vacuum to open and close the blend door.
3) Maybe the blades on the water pump are shot.
4) Heater core might be partially clogged.
And YES.....providing information on the truck's model year is important.

 

No need to ask a question such as "am I low on antifreeze". Check for yourself, it takes about 2 seconds.

Is the overflow canister full to the top line?

If it's empty, you have solved your own problem.

If the coolant is dangerously low, the truck will mostly blow hot air while moving, but blow cold air while stopped.