Heater issues

[Alistair E]

Need a bit of advice. Over the past few weeks, when I've tried demisting the windscreen by blowing hot air onto it, the screen has misted up further rather than clearing. Not drastically, but noticably. The car is a non aircon model.

I haven't really tried to locate the source of the problem but more recently I've been having other issues with the heater system so the other day, I decided to drop the bottom hose, add coolant, and bleed the system. I have been losing a smalla mount ot water before this and that has continued.

The other problem I have experienced is that even when the car is up to temperature, the heater sometimes blows cold air. This was the case tonight while I was stationery in traffic. But when I increased the revs to 2500-3000 for about twenty seconds it started to blow hot again.

Does anyone have any suggestions? I was thinking that maybe the heater matrix may be leaking slightly although the carpets don't appear to be damp. Car does seem to be damper inside than usual. Other thought was maybe a sticking thermostat.

Your thoughts would be gratefully received.

Alistair

[Big Lee M]

I'm sorry to say but it's your heater matrix, I had the same problem had to replace mine last winter.

[macspring]

If it was me,

I'd bet on you needing a new matrix, dash out to do.

Others to follow.

Kind regards.

[s2_bo]

I'm sorry to say but it's your heater matrix, I had the same problem had to replace mine last winter.

Same thing for me......
Euro Car parts sell them for about £50

Its a pita to change though!

[Big Lee M]

It's not too bad a job if you have somewhere to do it with a bit of heat, I did it in my mate garage in december last year when it was freezing. I got a genuine hearter matrix think it was only about £60, just thought I didn't want to be doing it again so buy the right part.I think it's a Valco unit in from the factory and the same I put back in.

[montez]

Mine steamed for about 2 months before it gave in completely (k-seal helps), It eventually gave way and I had steam poring out the vents as I was going along the M4 which was not good! Did mine on the drive in the cold, its not really that difficult a job it is just time consuming and frustrating. The hardest bit is getting the two bolts off holding the matrix in place on the bulk head, you have brake and fuel lines to contend with and it is quite a way down, I found the easiest way to do it was to remove the coil (3B).

There are some good detailed guides available on the forums which help with getting all the screws out of the dash.

[macspring]

Alistair,

You can postpone the replacement of the matrix by disconnecting the two water heater hoses as they go into the bulkhead at the rear of the engine bay, and connecting them together.

The only thing is that by do this is that you'll naturally have no heat or de-misting inside the car, which in this cold weather is not great.

When and if you are taking out the dash make sure to read all of the guides in advance.

There are two awkward screws one on either side of the centre of the dash, plus a "gotcha" one on the RHS of the inner section of the centre of the dash.

HTH a bit.

Kind regards.

[Alistair E]

It pains me to say it but thanks guys. Looking like the major job of dash out is looming very close. Lots of steam out of the vents this morning.

Thanks for the advice on the screws for the dash. I'll try and find the guides for its removal. Unless of course someone can easily provide a link.

Thanks again

Alistair

[Christophski]

Ok so I think I may have to do the same but does anyone think otherwise.

I have had my car for about 2 years and the heater has never been great. The car warms up and unless im in traffic or have just "booted" it I dont get any heat into the car. I too lose a little water but I think this is down to a leaky bleed screw (New hoses to fit in the garage). I dont have any wet in the car and I dont get condensation or smoke in the car when I put the heater on.

I have bled the thing and it worked fine for a month then went back to how it was.
If i leave the revs up and then let them fall whilst car is in gear I can hear bubbles when the car is warm (still no heat) Its not the head... Is it the heater matrix that needs doing or any other suggestions?

I am gradually ticking things off the "to do" list ie I now have a working rear wiper, The sunroof doesnt leak anymore and I have a new screen. left to fix is the Central locking and the heater. Then its Diff seals. otherwise all is good and would like to fix the heater thing due to this weather.

Cheers
Chris

[Greg_S]

Id check the flap is moving across properly to redirect air through the exchanger, mine had slipped a few teeth so never redirected air over the heat exchanger, so was only every mildly warm air.

[spink]

If it turns out to be the matrix it really helps having someone else helping or even 2 people,makes it almost easy(kind of)

[Christophski]

Where's this flap then? Mine does get warm in traffic thoug so is it likely to be something else?

[HPmuirt]

I had the "blows cold at idle" issue until recently. Mine would only blow hot air if the revs remained over 2k, but as soon as they dropped to idle, the air cooled down.

We had already back flushed the system as the obvious reason for this issue is that the water circuit, or heater matrix is partially blocked, so only gets enough hot water to maintain hot air when the revs are up.

We cured it by accident as when working in the engine bay, we noticed a few of the small water hoses under the IM were leaking crud and also looking rather hard and past it. When we changed these, on of them had a small lump of crud in one end that blocked about 75% of the hose but was the wrong shape to pass into the metal connector pipe so just sat there acting as a limiting valve.

As soon as this was removed and the system back flushed again but this time with all small pipes disconnected one at a time or replaced - no more cold air at idle

So my advice, check all your small water pipes and back flush the system and the heater matrix separately.

Cheers n

Si

[Christophski]

Right well I have the samcos to fit so I am going to back flush this with a mate then change the hoses and the back flush it again.

Cheers. i hope this works as Its FREEZING outside! Lol.

[macspring]

Christophski,

What ever happened, did you get your heat issue sorted ?