ZX cool air from vents

Paul Thomas · Post by **Paul Thomas** » 01 Mar 2004, 21:29

It definately works to some extent because I get very cold air when I turn it to cold but only mildly warm air when on hot.
Is access easier with the head-unit removed ?
I have already done all of the bulbs last year - thanks. (Of cource I could have dislodged something at the time to cause this problem and I wouldn't have noticed in the summer!!)

James.UK · Post by **James.UK** » 01 Mar 2004, 23:05

Assuming your fan is working ok, it sounds as though you have a problem with the Hot-cold control, an obstruction of some sort preventing it opening fully in some way? My car gets hot even with the fan turned off as long as its moving at 30-40 ish, and normal temp guage reading is 80.

goose · Post by **goose** » 02 Mar 2004, 00:19

i know it might sound stupid but check the heater control switch!!
change it with another and try that i cant seem to think wats wrong otherwise

Paul Thomas · Post by **Paul Thomas** » 02 Mar 2004, 20:46

Heater control switch ??
To the best of my knowledge I don't have one.
There is a fan switch to select the speed which works OK and the temperature control knob.

James.UK · Post by **James.UK** » 02 Mar 2004, 20:56

Hi Paul, I think your problem lies between the heater control knob and the shut-off valve in the water pipe? i.e. turning the knob is failing to operate the valve. I think you need to get under and have a good close look at exactly what happens as you turn the heat control knob..

Paul Thomas · Post by **Paul Thomas** » 02 Mar 2004, 21:55

Other posts on this forum state that the heater matrix is straight through on the ZX and therefore adjusting the temperature only adjusts a flap of some kind to direct the heat.
Can anyone confirm this ?

James.UK · Post by **James.UK** » 02 Mar 2004, 22:54

Ooops! hhmmm come to think of it thats true, was my 323f mazda that had a valve! Sorry Paul [:I]... Ok, but the problem is still exactly the same? you need to find out why turning the heater control doesn't open the flap? the only way to find out is to have a look? small mirror may come in handy? Turn the control and watch what happens at the flap end?
Is the control hard to turn? Cable seized? bent? Does it turn very easily? cable come off one end? broken? You really need to have a look.

Russell · Post by **Russell** » 03 Mar 2004, 03:12

Hi Paul,
It sounds to me as if your heater matrix is partially blocked. I would try pulling the hoses off the bulkhead to the matrix and getting a garden hose to flush the heater matrix through.
Have you ever put any rad seal or other gunk in?
These can block up the matrix which tends to have smaller elements than almost anywhere else in the system.
best of luck
Russell [:)][:)]

Paul Thomas · Post by **Paul Thomas** » 03 Mar 2004, 14:43

I have flushed the system thoroughly with 2-part Holts and am fairly confident it is flowing ok.
I have never used a sealant in the last 66,000 miles anyway.
The heater control isn't stiff or anything, I'll have to have a look under the dashboard.

sooty · Post by **sooty** » 04 Mar 2004, 01:24

Yes, the ZX matrix is in full circuit all the time and has no valve to control the flow/temperature. The temperature is controlled by the amount of air flow allowed through the matrix, controlled by the flaps.
You say you recently fitted a radio, have you double checked you have not disturbed any of the controls or ducts causing your loss of heat.
When you did the flushout did you put the hose through the matrix as well or just the rad. because you may well leave some gunge behind in the matrix allthough both in & out pipes are hot you may not have full flow due to partial blockage.

Paul Thomas · Post by **Paul Thomas** » 05 Mar 2004, 20:22

Sooty
I have to confess I didn't know that the pipes came off the bulkhead so didn't want to damage them. I therefore only flushed the system from the thermostat and radiator outlets.
The new stereo has a cd-changer cable, new speaker cables,3xRCA cables all in the vicinity as well as a new multi-way plug loom so it entirely possible I have disturbed something.
I will try and pop the stereo out at the weekend and take a look. should I be able to see the matrix or control cables from there ?