AU heater gone cold

XBCoupeGuy · 18-07-2011, 12:51 PM

Hi all,

I'm hoping you guys have come across this before and can offer advice on a likely cause.

I did a search but got a squillion threads and didn't find anything covering this specific fault in the time I could spare to read them.

I have a Series 1 AU Wagon. Yesterday the heater decided to stop working. It was working fine on the way out, in fact I had to turn it down as I was getting too warm, but on the way home I was cold and discovered that no matter what I did, it would only flow cold air.

The car is in beautiful condition, the cooling system is perfect, car is always serviced etc, so I'm guessing it's probably a heater control issue. Maybe a wire, vacuum line or similar has come off the back of the controller and it's not opening the flap to allow warm air in?

Has anyone had this before and aware of the cause?

Thanks
Darren

mik · 18-07-2011, 02:07 PM

hmmm dunno mate, i think my first check would be the heater tap, to make sure its operating, easiest on some ramps i think, the tap is under the inlet manifold area from memory, or alternativly you could probably feel the heater hoses going into and out of the firewall, if they are both hot i`would bet its a flap/heater control malfunction, the flaps and heater tap are controlled by vacuum mostly, once you`ve sussed this out go from there.

JMO · 18-07-2011, 05:19 PM

It's could quite possibly be the temperature control cable which has come loose off the back of the heater controls. Open up the glovebox and you should be able to see the cable/wire which is in a black sleeve. As you turn the heater control, watch the cable as it moves and once you've reached the hottest setting, see if you can move it any further in the same dierction.

The temperature control wire clips onto the back of the heater controls and it is quite common for this plastic to crack which gives the cable too much slack and doesn't allow the flap to open/close fully.

XBCoupeGuy · 18-07-2011, 07:16 PM

Thanks guys, it only happened yesterday so I haven't had a chance to check it out.
I appreciate the suggestions. I'll try to have a look this weekend let you know what I find.

falconhell74 · 18-07-2011, 07:29 PM

Sounds like a vacc leak if it happened as quick as that , mate had a similar prob in his au xr6 , turned out a rat had chewed through his vacc hose

Rambunctious · 19-07-2011, 06:01 PM

Last but not least check your thermostat is operating correctly and not locked open, that was the problem I had.

XBCoupeGuy · 19-07-2011, 10:33 PM

Quote:

Originally Posted by Rambunctious

Last but not least check your thermostat is operating correctly and not locked open, that was the problem I had.

I was thinking the same. I was looking at the temp gauge and it seemed pretty low compared to normal (I think), but it was also a freezing cold afternoon and I was driving in the country, so I figured lots of cold air could be keeping the engine temp right down.

Funnily enough, it still wouldn't work on the way to work this morning but started working on the way home this afternoon. It's not full heat but definitely warm air.

Now I didn't touch anything (move any controls etc) so it's unlikely to be a control linkage or similar. I'm thinking sticky thermostat or possibly some sort of blockage in the heater tap. Coolant system is regularly serviced though, but anything is possible.

Thanks for the replies guys. I'll have a look on the weekend and let you know what I find.