Noticed this on my new TT, after a long drive immediately after i turn the engine off i can hear like a gurgling/boiling type noise which seems to be coming from under the dash, lasts about 2-3 minutes before subsiding. I am quite certain its NOT AIV's, as it is significantly more audible inside the cabin, and can only be heard with the engine off, which does not seem to fit the usual symptoms of AIV gurgle. Not boiling coolant either (aftermarket temp gauge sits solid as a rock on 80-85 degrees). i was thinking maybe heater core? but i cant see how it can make a noise like this, and it has no evidence of leaking... Any ideas what it could be? :zlove:
You'll need to set the climate control to max temp with the car running in order to get some flow through the heater core. The cooler weather we are having at the moment will help achieve this, maybe try it first thing in the morning when a bit cooler ambient temp.
drive it up hill with the heater open/on, pull over before you reach the top and add water. My car did the same thing, it took a wile to get the trapped air out of the core( got in there when i replaced the heater hoses) but eventually I got it out.