Heating blows COLD ONLY, engine temp etc all normal... Help!

[Lucky29]

Hi all,

I have a 2.5 TDI V6 A4 Estate and the heating blows only cold air out! The engine warms up to 90 within 10 mins or so, does not over heat and runs like a dream.

Garage has checked over the radiator etc and no issues there and they reckon it could be that the thermostat is stuck open. Obviously the thermostat on this car is a large job which don't really want to fork out for if it may not even be this that is the problem!

Does anyone have any suggestions or prior experience with this problem? Obviously deep in to winter now and been dealing with a frozen windscreen (inside) for a while

Any help will be greatly appreciated.

Thanks in advance

 

[pauldazzle]

I doubt the stat is stuck open if the engine is getting up to 90 that quickly.
Check the heater matrix pipes ( located on the bulkhead near the battery) to see if they're getting hot. If they are you have heater flap motor stuck which is stopping warm air entering the cabin. Diagnostic with VCDS would show a heater flap moter fault code if that's the case.

 

[Mike B]

Agreed it wont be the stat and most likely the main flap is stuck closed.My 2.5 has temperamental flaps too mainly the demister which wont open sometimes.Its just begun to work after a few days stuck just as I was thinking of getting at the motor.I have taken it apart before and cleaned and regreased but it will probably need replacement now.Needs the glove box out so if you do this you can get to the flap and motor stuck on yours and maybe kickstart it by wriggling the connecting arms..Diagnostics will confirm but you can sense something is wrong if you cant hear any movement when selecting controls..Sometimes I get the feeling that playing with the controls and/or bumps in the road can jerk the cogs inside the motor to restart.The main flap might move if you play with the heat settings.

 

[Lucky29]

I doubt the stat is stuck open if the engine is getting up to 90 that quickly.
Check the heater matrix pipes ( located on the bulkhead near the battery) to see if they're getting hot. If they are you have heater flap motor stuck which is stopping warm air entering the cabin. Diagnostic with VCDS would show a heater flap moter fault code if that's the case.

Thanks very much pauldazzle!

I have checked the pipes and they’re getting warm but not hot... not sure how hot they should be getting?

Will probably get a diagnostic done ASAP, freezing my nuts off on the way to work

 

[Lucky29]

Agreed it wont be the stat and most likely the main flap is stuck closed.My 2.5 has temperamental flaps too mainly the demister which wont open sometimes.Its just begun to work after a few days stuck just as I was thinking of getting at the motor.I have taken it apart before and cleaned and regreased but it will probably need replacement now.Needs the glove box out so if you do this you can get to the flap and motor stuck on yours and maybe kickstart it by wriggling the connecting arms..Diagnostics will confirm but you can sense something is wrong if you cant hear any movement when selecting controls..Sometimes I get the feeling that playing with the controls and/or bumps in the road can jerk the cogs inside the motor to restart.The main flap might move if you play with the heat settings.

Yeah can’t hear any movement with playing with climate controls! It hasn’t worked since I bought the car so will try to give it a play if I can figure out how to get to it through the glove box.

Otherwise straight up replacement may just be best as I have no idea how long the heating hasn’t worked for!

Thanks for your advice!

 

[Mike B]

Its easy to take out the box and have a look for movement when you use the controls.Unlikely that all the motors are stuck but it is a common problem and replacements are dear.I think there are three and one is on the drivers side.There are guides on here.The cogs wear and don't mesh right.Also the grease inside hardens which can itself cause sticking.I cleaned mine out and used Vaseline .These little clever gadgets aren't meant to last for ever fine while working but after 15 years or more they are likely to give up and manual levers will always outlast them.Fortunately my 04 just escapes the new diesel MOT rules so I can justify spending a little on her.If you get the box out and get them moving by wiggling the control arms it would give you the heat until better weather comes.Dont see why you cant at least move the main flap open even if it sticks like that for now

 

[Lucky29]

Its easy to take out the box and have a look for movement when you use the controls.Unlikely that all the motors are stuck but it is a common problem and replacements are dear.I think there are three and one is on the drivers side.There are guides on here.The cogs wear and don't mesh right.Also the grease inside hardens which can itself cause sticking.I cleaned mine out and used Vaseline .These little clever gadgets aren't meant to last for ever fine while working but after 15 years or more they are likely to give up and manual levers will always outlast them.Fortunately my 04 just escapes the new diesel MOT rules so I can justify spending a little on her.If you get the box out and get them moving by wiggling the control arms it would give you the heat until better weather comes.Dont see why you cant at least move the main flap open even if it sticks like that for now

Ok, thanks Mike,

I'll give it a crack at work today, any idea whereabouts the advice on how to access said flaps is on the forum? I agree, may just stick the flaps open so that I have heat!

 

[Mike B]

You cant access all the flaps only the large heat flap which I saw deep behind the centre of the fascia.If its not moving you might be able to reach and pull it open.If you find nothing wrong then might be the matrix is blocked then you can only try flushing it or replacing

 

[Lucky29]

Its easy to take out the box and have a look for movement when you use the controls.Unlikely that all the motors are stuck but it is a common problem and replacements are dear.I think there are three and one is on the drivers side.There are guides on here.The cogs wear and don't mesh right.Also the grease inside hardens which can itself cause sticking.I cleaned mine out and used Vaseline .These little clever gadgets aren't meant to last for ever fine while working but after 15 years or more they are likely to give up and manual levers will always outlast them.Fortunately my 04 just escapes the new diesel MOT rules so I can justify spending a little on her.If you get the box out and get them moving by wiggling the control arms it would give you the heat until better weather comes.Dont see why you cant at least move the main flap open even if it sticks like that for now

Tried today to remove the glove box but it turns out that the 6 CD changer is blocking the last few bolts to remove it!! Very frustrating!

Any way of getting past this problem without trying to get hold of the Audi tools to get it out?

Thanks

 

[Lucky29]

You cant access all the flaps only the large heat flap which I saw deep behind the centre of the fascia.If its not moving you might be able to reach and pull it open.If you find nothing wrong then might be the matrix is blocked then you can only try flushing it or replacing

Tried today to remove the glove box but it turns out that the 6 CD changer is blocking the last few bolts to remove it!! Very frustrating!

Any way of getting past this problem without trying to get hold of the Audi tools to get it out?

Thanks

 

[Mike B]

No changer in mine.Can you hear any movement now ?Should be quite obvious with engine off.If you can its worth thinking about the matrix cos the intake should get hot when the temp gets to 90 and they are prone to blockages.If it doesn't and you are stuck on the box it would be worth reverse flushing the matrix with a hose.

 

[stevey83]

Youll have to remove the whole glovebox including the cd changer. Mine does the same, i get them moving then they seize up a few weeks later. They are a pain in the ****! Anyone know how much they are from Audi to replce new? I imagine all the ebay ones will be the same.