Just bought an A3 2.0 tdi 2017. Every time I stop I hear a gurgling sound coming from the dash or matrix. Done all tests for head gasket, no leaks or coolant loss!?????????

If bought from a dealer I'd recommend getting it back to them for a diagnostic as they should fix it free of charge if bought within the last 30 days. 

Thanks, I have done but they don't know what the issue is. They think it's coming from the matrix.   All diagnostics show no problems so I'm unsure what it could be and tempted to back out if the purchase. Some forums say it's normal and to do with cooling the turbos or something?

Can't say I've heard of it. You could always get it checked by Audi or an independent Audi specialist 

Possibly it's the air con. My wife's Yeti purrs like a cat when the AC is running.