Heater blowing cold air 99% of the time

[Sauniere]

Hi,

I have a 02 Cupra and the heater just isn't working properly. I had noticed that on occasions cold air suddenly started blowing out of the wrong outlet for short periods of time but wondered if this was some way of regulating the interior temperature. Anyway after a while it became the norm that cold air blows out of where I don't want it, regardless of temp setting. It occasionally blows warm air from the right vent but not very often now. This has become quite urgent due to the time of year, I could demist using the air con setting but as the temp is now below 3 degrees it won't come on.

When I set the heater to demist the windscreen I can sometimes here a force 10 gale blowing behind the dashboard. If I open the dashboard vents freezing cold air gushes out at a pretty high force.

I've had this in to a Wincanton service centre (my wife works for Wincanton & their fleet cars are all VW) and they told me that it could be thermostat, heater matrix, flap motor, climate control unit. They stripped down the interior to check what it was and couldn't find out for some reason. The have decided to change the thermostat as it is relatively cheap. Any way it wasn't that. I have since had the bill for this work and it comes to £200without a fix about £12 of that being the thermostat, rest is labour!! The next step they say is to strip the dash out and replace the radiator which is a day of labour and around £50 for the radiator

It's doing my head in. I've had someone clean out the rad using a dishwasher tablet and then flushed it out. This seemed to work for about a day but it could have been a total coincidence.

Sorry for the long winded explanation but I just need help in diagnosing this problem otherwise it looks like I'll be out of pocket by £500 and still without a warm car.

Any help would be much appreciated

 

[CapnAHAB]

Could well be a blockage perhaps in the heater matrix?.

You'll have two water pipes feeding through the firewall into the dash area.

These are the inlet and outlet of the heater matrix.

when the car is warm check that both of these pipes are hot. If only one is hot and the other is cold, then there's a heater matrix fault.

It was a bugger of a job on the Corrado, but you'll get it done yourself if you set aside a saturday. Basically i ordered a new matrix from GSF (35 quid for the rado) then fitted it myself. all fine from there on in.

 

[SHADY-NINJA]

i think you may have a blockage in the heater exchange matrix.
have you had some recent engine work done to the car.
the reason is some times the heater pipes are exposed
and and gets contaminated. this is where blokage occurs.
hence cold air.
get somone to bleed the heater matrix or get a second hand one.

 

[dan__smith]

What does your outside temperature sensor say?

 

[Sauniere]

Thanks for the replies. The only work I've had done on the car recently is re gassing of the air con strangely enough although this problem was evident before then just not as bad.

I'll check the inlet outlet pipes but I think that the mechanic at the garage did check that (one thing they did do!)


Outside temp is being reported as expected Dan.

 

[MDS]

Checked your fuses ?

 

[dan__smith]

Only reason I asked that is because my outside temp sensor was giving strange readings and producing only hot / only cold temperatures in the cabin.

 

[Lodgey180]

temp control motor .... 8D2 820 511 D = 83.90 + vat

 

[Sauniere]

I did a bit of searching on here yesterday afternoon and found a post regarding removing the kicker boards in the front footwells in order to see the flaps moving. My wife took my car back to her garage this morning and asked them to check this out.

I've just had word that they've done that and the flaps are changing/moving on their own hence no warm air when I want it and where I want it. It's a poor state of affairs when you have to tell the garage how to repair your damn car yourself.

Does anyone know if this is more likely to be a flap motor replacement or the main control unit replaced? How much is a new flap motor?

 

[Lodgey180]

I did a bit of searching on here yesterday afternoon and found a post regarding removing the kicker boards in the front footwells in order to see the flaps moving. My wife took my car back to her garage this morning and asked them to check this out.

I've just had word that they've done that and the flaps are changing/moving on their own hence no warm air when I want it and where I want it. It's a poor state of affairs when you have to tell the garage how to repair your damn car yourself.

Does anyone know if this is more likely to be a flap motor replacement or the main control unit replaced? How much is a new flap motor?

temp control motor .... 8D2 820 511 D = 83.90 + vat

thats what ive price 4 u

 

[Sauniere]

temp control motor .... 8D2 820 511 D = 83.90 + vat

thats what ive price 4 u

Sorry mate, it didn't register at all. Cheers!

Don't suppose you know if it's a dashboard out job or not ? I know the unit sits behind the glove box but I've seen on some of the vw/audi forums that depending on make of car some can be done just by removing glove box

 

[Lodgey180]

no i think it will be fiddly but you should get it. not entierly sure on that tho

 

[Sauniere]

Further checks have revealed that the flap control motor behind the glove box is actually working. However, the airflow flaps themselves seem to be changing of their own volition without any input via the control unit.

Also there is a flap situated behind the air con unit & the radiator that switches between cold air from the air con and warm air from the heater. This is not moving as it should and I need to know where this flap is controlled from. Any ideas anyone?

Sorry if I'm being repetitive but I don't understand fully how the system works and am relaying info as I get it.

 

[Goldie]

Hello mate. Did you have any joy sorting your car? Mines doing the exact same thing. Cars an 02 leon cupra brought new has had this prob for around 3 yrs now! Doing my head in. You can hear the air being blown behind the dash then open the vent and cold air blasts out! Then you cant control where you want the air..

 

[Fl@pper]

Further checks have revealed that the flap control motor behind the glove box is actually working. However, the airflow flaps themselves seem to be changing of their own volition without any input via the control unit.

can you get at it to remove it ? see if it's actually connected to the flap and that the flap is moving as it should ?

might be able to get some diagrams if it helps any ?


failing that first call is check the water pipes in/out the matrix are similar heat with no blower on - easier to get at in the engine bay

if no hot water getting in it will blow cold all day no matter what flaps are doing

 

[Goldie]

The heater pipes are all fine going into the matrix on mine. No blockage at all. Defo some crazy prob under the dash with the heater box or wiring for it..

 

[Sauniere]

Hello mate. Did you have any joy sorting your car? Mines doing the exact same thing. Cars an 02 leon cupra brought new has had this prob for around 3 yrs now! Doing my head in. You can hear the air being blown behind the dash then open the vent and cold air blasts out! Then you cant control where you want the air..

Hi mate, sorry for not replying sooner, been away for a few days.

The problem is exactly what Lodgey said. It's the temp flap motor assembly. I had a few choice words with the garage in question about being unhappy about the service etc and I gave them the cruise control diagnostic info that's floating about on the forum & they ran it & got 70+ faults most of them pointing back to that. I'm waiting to book the car in to have it replaced but it should be next week. Price was exactly what Lodgey said as well although there's labour on top of that (book time is 4 hours apparently) In the meantime they forcibly moved the flap directing hot air into the car. I still can't change the temp or the outlet but at least it's warm and the windscreen demists ok

 

[mea02mr]

Hi did this fix the problem i have the same problem with mine, replaced the motor and it still doesnt work!

 

[Sauniere]

#mea02mr

It seemed to work at first, at least it worked for the rest of the cold period. First use of the heater the following September the same problem occurred. I got rid of the car in November with it still not working.

Good luck with yours mate