A4 B7 no heat inside cabin
Hi all, I've read a few of the posts on here about this but it doesn't appear to have been answered.
Car = A4 - B7 2.0 4 cylinder 2005 model.
problem. car started to judder at idle when just started (only did this 3 times for about 20 secs)
had a look under bonnet for anything unusual - nothing apparent.
noticed no heat in cabin the same day. Temp guage on normal.
Drove car in evening - still no heat for a mile then temp guage rose to 3/4 for aout 10 secs then dropped back to normal operating temp - then heat started working in car.
heat stopped again the next day. I did a bleed on the engine coolant from both the heater matrix top hose and from the allen key bleed point on the metal pipe joined to the rad top hose. still no heat.
I have noticed that the heater matrix top pipe is cold and the bottom one is hot - tried a bleed again and it has no air.
done a heater matrix flush - all clear. bled system again.
***Where do the heater matrix pipes come from and go to? and what valves are in that system that could stop the water flow?**** Car is a 60 000 Mile well serviced and looked after car.
Cam belt and Audi water pump replacement 30,000 miles ago and 2 years.
***Does the heater inside the car stop water circulating through the heater matrix when cold is selected or does it just stop the flow of air through the heat exchanger***.
Any help on this issue would be greatly appreciated.