I have a 2015 A3 Quattro. I have no heat coming from the vents at any hot setting. The blower seems to be working fine but get no heat control or hot air in the vents.

The passenger side has a little bit of heat at the highest setting but the driver side is cold.  How do I troubleshoot this issue.

thks in advance.

Some vehicles have a perforated bag of beads in the coolant expansion bottle to boost the coolant. These have been known to burst and the beads clog the heater matrix. Check to see if yours has a bag and if its intact.

More than likely it's an airlock somewhere and the system needs bled, thermostat issue or water pump issue.

 

Hello David,

Never too old to learn as they say......’Perforated bag of beads in the coolant expansion tank to boost the coolant’.

Could you enlighten us on the makes of these vehicles which come with these bags as original equipment? Also, in what way are they supposed to ‘boost’ the coolant. 

Hello Michael, 

David mentions possible thermostat or water pump causes. Could you let us know if the car gets up to Normal (90) on the gauge after a couple of miles or not? 

Kind regards,

Gareth. 

Some of the A3's have them seemingly. Probably other models too.  Other VAG's use them also. Its silica or something in them to boost the properties of the coolant as far as I understand. Some people remove them to prevent them bursting.

 

Many thanks,

Strange they should submerge such things in the coolant reservoir as original equipment. I wonder why they don’t simply add whatever the chemical is ( doubt silica) to the coolant fluid? 

Live and learn as they say. 

 No loss of water no over heating can't see the bag but it's full of water drives mint not any issues just not blowing any heat.  Did anyone fix this.  

Iv got Audi A3 tdi 2.0l 2013 and the problem I’m having is I let it get up to temp (90c) turn the heat on hot and it’s hot then a few seconds later goes cool.  Then turn it off for a few minutes then the same happens. 

On 10/16/2023 at 1:06 PM, Jonboy walton said:

Iv got Audi A3 tdi 2.0l 2013 and the problem I’m having is I let it get up to temp (90c) turn the heat on hot and it’s hot then a few seconds later goes cool.  Then turn it off for a few minutes then the same happens. 

Did you ever get this issue fixed?

A wee bit further info. I had an issue on my Skoda VRS where the fans etc were working but no heat on passenger side vents. Turned out to be a thermistor in the vent pipe was reading high temp so hot air flaps didn't open as it thought it was already too warm. Replaced thermistor and all working again.

Info just in case someone else has a similar issue.