O.A.O

On 1/7/2020 at 4:21 PM, avtech999 said:

I recently bought a 14 plate A3 with very high mileage for not much money, the only problem it had was the heating didn't work and apparently no-one could find the solution (someone gave up on it). The problem was the heater matrix was blocked. The heating system in the A3 (certianly the 1.6tdi) contains a sealant in a bag at the bottom of the header tank which bursts when the temperature strays outside the recomended temperature (according to an independant I discussed it with). It is there to prevent a catastrophic loss of coolant if there is a leak and "get you home". the problem is, if it bursts accidentally, it clogs up the collant system and typically finds it's way to the heater matrix where it sits - blocking it. You can check if this is the problem by finding the two pipes which go through the bulkhead and feeling them when the enginge is warm. On my little car, the top one of the two was nice and cosy and the bottom stone cold. when I took the matrix out, it looked imaculate but as soon as the new one was fitted and fluids topped up again properly, the car was right as rain and has been since. I tried flushing fluid through the old one from a tap and with pressure but nothing would go through it.

Can't say this is your definitive answer, but it's certainly worth checking! (As a side note, I was quoted £900 for parts and labour but did the job myself for around £90 in parts + half a day of my time). Hope this helps.

Hi Huw,

Unfortunately I have found myself in a similar position as yourself, the sealant bag burst and has clogged the heater matrix. If I may ask, where did you get the parts and any tips on how to replace it.