High_PSI

iTrader: (50)

How does old coolant effect the heater? I know if your thermostat is stuck open your car runs cold but why old coolant?

blaze_125

iTrader: (8)

In my mind... as time go by, the heat exchange properties of coolant degrade.
Has my point been validated yet? I don't know, and I have yet to try.

I have the same problem and my gut feeling tells me I should change the coolant, but my hands tell me it's too cold right now.
1 thing I know, I added fresh coolant to my system a few months ago(to top it) and my heater blows hotter air than it did before I topped it.

fe2o3

have you looked above the accelerator pedal at the flapper gear assembly on the side of the heater box to check the linkage or gear movement? As you turn the hot/cold dial, you should see the gear rolling gradually open to either direction.
Climate controls on our cars kinda suck.

KX250Fmotoracer

No offense- old coolant is NOT the reason this is happening

Sounds like a blend door issue in the heater box

HornstarBU

iTrader: (7)

My blend door broke, the little gear on the side...so even though the knob say "i'm on heat" it's not. I have to reach up under the dash, and turn it by hand. IT's tough, it's gonna break one of these days bad enough that i can't move it anymore....I hope it breaks on A/C.

mink

We had this problem. First, we found out that the plastic gears behind the actual heat adjustment knob were stuck. (Eventually the knob snapped off, as it had been getting more and more "sticky" over time.) The plastic gears connect your temperature knob to a cable that basically moves a door back and forth to allow either all hot air or all cool air, OR A BLEND of both, into your car. (The cabin, that is.) This is called the blender door. It is VERY common on OZ Rally Lancers for this cable to develop a kink/bend in it. Therefore the cable isn't sliding back and forth properly, and so your blender door gets stuck, in our case on all "cold" air. We checked everything from those gears behind the control unit, to our thermostat (which we even replaced), to our heater core (we did a radiator flush AND hand-flushed the heater core itself in case it was clogged)... Eventually we followed that stupid cable from the back of the white plastic knob gears, down through the dash, to where it ends up by the driver's shins up against the cabin side of the firewall. It was obvious that the cable was kinked, so even when the heater knob was being turned back and forth, the whole plastic cable tube itself was what was pulling back and forth, as opposed to the actual CABLE WIRE inside, which is actually what you want to be moving. Hence, the knob in the car seemed to be adjusting stuff, but actually wasn't capable of moving that blender door anymore. We just hand-forced the blender door to heat, and left it at that. Eventually we will re-run that cable, but as it's the dead of Winter here in Michigan, we don't need to tackle that just yet. Feel free to email us for more direct help on this, as it seems to be a super common problem- there's threads all over the web about this problem.

imhenryd

My heater works when I'm driving but whenever I come to a stop And sit at idle it starts blowing cold air, any ideas?

02modlanceroz

iTrader: (2)

Is your radiator and overflow both full?