[tewkes28]

First off the car is 2006 ST. I bought it used a few months ago, and it has 40k on it.

As many of you know it is cold up here in the northern states.
So I noticed this a few weeks ago but it didn't start to bother me until lately when the mornings have been below freezing.

I'll warm my car up in the morning. When I get in to go, the engine will be up to temp. but there is not heat coming from the vents/defroster. It will take a long time before heat eventually starts to come out. However it does not produce any heat while the car is at idle or under 2000 rpms.

Is this a thermostat issue, or some kind of sensor?

When I'm driving on the freeway it doesn't bother me cause it's nice and warm, but a lot of my driving is stop and go and the car never warms up much.

Help me out, I'm cold!!!

Thanks

 

[ArcticMynx]

it actgually sounds like the blower motors not working.. when your at freeway speeds the forced air induction forces air into the cabin which warms it..

sit in the car and turn the key to the on position and turn the fan on can you hear the blower motor

if you cannot you may have a bad resistor
if you do hear it with no flow one of your directors may be stuck, the intake is plugged or your heatercore may be plugged aswel ( Either coolant flow or airflow)..

I have the opposite problem XD I have TONS of airflow yet no heat ( My Thermostat is failsafe'd, it failed)

 

[MeJuztChillin]

Could also be weak water pump I had an 02 ZTS that had no heat untill it reved over 2 k and it was a water pump

 

[tewkes28]

The blower motor definetly works. I can hear it blowing and feel it.

The weak water pump is a possibilty. I've never heard of this but I'll look into it.

My first assumptiom was the thermostat. I thought maybe the thermostat was getting stuck.

 

[duffer1960]

Coolant level

You could be low on coolant. When just sitting it may not beh high enough for the pump to circulate it, therefore it is not getting to the heater core. Once you start driving, it sloshes around enough that the pump will now circulate it and that is why you have heat while driving and not at idle.

 

[bluefront]

For sure check the coolant level.... an air pocket can develop and it usually restricts coolant flow through the heater.

The other thing that could cause this problem involves the heat control cables from the temperature knob. If that knob feels loose when you turn it, something is wrong. It could be a cable issue, or an internal problem inside the heater box (the air-mix door might not be moving).

I've never had my heater box apart, but I've seen broken air-mix door linkage. In your case the door would just stay in the closed position, or almost closed which would let a little heat into the cabin.

I think if you look at the heater box by the gas pedal, you should see part of this cable/linkage move when you turn the heat knob.

 

[tewkes28]

I'll check the coolant. Last time I was in the engine bay ( a month or so ago) I remember seeing the coolant in the overflow box and it was not too low, but I'll check it again.

As far as the controls or the linkage. I'm not sure if it's that because it doesn't feel loose and I can adjust the heat, when it's working, from hot to colder with the knobs.

 

[Super Dave 26]

I'm having a similar problem on our '01 ZTS. Coolant level is fine. Thermostat was new. At idle, cool air. Blower works fine. If I push on the throttle at a stop, I will get warm air. Moving under throttle, heat is good. Sitting at a stop at idle, air gets cool.

Is there a vacuum operated blend door? Is there a vacuum operated shut off for the heater core?

It was 5 today, and I just discovered this last night. Sweet! LOL!

 

[PDQEagle]

First, check for air flow. Direct air to steering wheel level, turn up blower and check for air flow.

Another, push the button to recirc air flow rather that from outside. Trying to cool down freezing temps takes a lot more heat from the unit than just maintaining inside warm air.

 

[Super Dave 26]

First, check for air flow. Direct air to steering wheel level, turn up blower and check for air flow.

Another, push the button to recirc air flow rather that from outside. Trying to cool down freezing temps takes a lot more heat from the unit than just maintaining inside warm air.

Not sure if you're directing that to me, but...

Air flow is excellent. Normal.

Recirc is a problem in snowy climates as you recirculate the snow that builds up in the wheel wells, then you can't see with all the condensation on the windows.

We've owned the car since new in October 2000, so, I recognize that you're looking to limit the issues. But this is a new problem that isn't related specifically to weather. We've had colder before with heat.

Does anyone know of a vacuum diagram online?


Thanks for the help too!

 

[bluefront]

I'm not sure about earlier models.....but I'm fairly certain there are no vacuum lines running into my cabin ('06). That means the linkage is mechanical or electrical (haven't seen any electric motors on the linkage either). So.....I think the whole heater box is mechanical controlled. The exception would be the recirc. door. Controlled by a switch.... which means an electric motor opens/closes the door.

If you hear noises as you turn the mode knob the linkage is probably working.

Which leaves a coolant circulation problem. Sometimes the heater core gets blockage with crap build-up. A coolant flush at a shop might help....if they do it right. One way to tell if the heater core is blocked is to touch the coolant lines going into the cabin. Both the line going in and the line coming out should be too hot to touch after the car is warmed up. A cool line means the core is somehow blocked. If you know what you're doing, you can flush the core with a water hose.

The other problem.....an air pocket in the core. Sometimes you can get the air out by jacking the front end of the car way up, and running the car on high idle till the heater gets hot.....might take a while.

Good luck.

 

[tukaniSVT]

When I had this problem ... after all of this kind of checking ... IT WAS JUST THE FUSE ...

So I would also check that.

-Ray-

 

[Super Dave 26]

A fuse for what? I have no apparent electrical issue.

 

[tukaniSVT]

It won't look like an electrical issue, but it's the fuse that controls the heater / AC fan ...

I got this from my mechanic that fixed it for me.

 

[Super Dave 26]

It won't look like an electrical issue, but it's the fuse that controls the heater / AC fan ...

I got this from my mechanic that fixed it for me.

What was your specific problem? No blower motor? AC clutch not engaging if you can elaborate?

 

[tewkes28]

Mine is definetly not the blower motor, or box linkage. All that stuff works for sure.

 

[svtf1417]

i swear this is a common focus issue. my SVT does the same thing...well sorta. mine will almost never heat up all the way unless im driving around town in 5th gear instead of 6th, or driving over 2K. my heat doesnt go away sitting at idle tho when its warm. and i have plenty of heat on the highway too.

 

[tewkes28]

i swear this is a common focus issue. my SVT does the same thing...well sorta. mine will almost never heat up all the way unless im driving around town in 5th gear instead of 6th, or driving over 2K. my heat doesnt go away sitting at idle tho when its warm. and i have plenty of heat on the highway too.

Good another Michigander with the same problem. Well not really good, but you know.

I've been taking the freeway to work in the morning because it actually blows warm air. As soon as I get off the freeway it starts to get cold.

 

[chefster]

Ok now that my new pulleys are on...my heat is kickin ass...i think maybe you serpentine is slippin? I don't know wtf [bawling] [wave] [clap] [chair] [driving]

 

[Super Dave 26]

kickin ass...i think maybe you serpentine is slippin? I don't know .

Wouldn't it be more likely to slip at higher RPM's vs low?