Hi, my mk6 heater will only blow warm air even after a long run with the control knob at max temp, however, if I turn it down to the min cold setting it blows cold air through which would suggest the control knob is doing its job, the hose on the right going to the heater matrix gets hot but the one on the left only gets warm, the bottom radiator hose doe's not heat up either, I have squeezed all the hoses until I have arms like Popey but still no heat.
Both thermostat and pump were replaced about nine months ago. Sorry its a bit long winded of me.
Thanks in advance, Joe

 

It does sound like thermostat, what does the gauge read?

Martin

 

The temp gauge runs at 3/4 the way up, I have had the car 9 years and has always run at this.
Joe

 

That is fine then, in that case I would make sure the heater valve is working correctly. It is strange that the bottom hose is cold though.

Martin

 

/I]Hi Martin, thanks for the input, won't doing anything until next week so will let you know then what if anything comes of it, was thinking of doing a full system flush in particular the heater matrix and radiator, I have read about heater valve and it seems to be tricky to get to.
Cheers Joe

 

Temp gauge 3/4 of the way up is too hot, it should sit bang in the middle.

 

Ok thanks for that, as I said I am going to try a full system flush and see what the doe's ??

 

Hi all, just an update on my heater problem, I have drained the system and refilled it, ran the car up to normal temp and had some success as the bottom radiator hose got hot which it was not doing so before, as for the heater still only blows warm air, what I have noticed is that with the blowers on and starting at the cold setting and slowly turning it to the hot setting there is no sign of any temp change until the control knob is about 1/4 of the way into the red segment, thanks for the help in the past and for any in the future.
Joe

 

Perhaps there was a blockage impeding the flow. As to the problem, as I say it's probably the HCV.

Martin

 

Hi Martin, thanks for that, I have looked at post about the HCV but I'm not sure where mine would be as some seem to think it's accesed through the bulkhead under the scuttle in front of the windscreen and others it's a resister type? Accesed via the drivers foot well, as I say it's a 2003 on a 52 plate, going to have to do some digging.
Many thanks Joe

 

I am not particularly into Fiesta's, so don't where it is, but should think you would need to dismantle the dash, as that's where the matrix is.

I do know the valve is controlled by the ECU via PWM and it's a common fault.

Martin

 

Hi, sorry I have not given an update on my mk6 heater problem put it looks like a mega blockage in the matrix, going to try some de-scaler ???? through it and if that fails its either the whole dash out or a box of matches.
Regards Joe

 

You could try disconnecting the 2 hoses on the back of the engine that go to the matrix and run a hosepipe through both ways?


Also what colour is your antifreeze? If it has had the blue stuff put in at any point it will react with the pink and turn to jelly!

 

Thanks for all the advice, it's finally sorted, back flushed the heater matrix which was full of gunge gets nice and hot now.