I have a gurgle under dash on passenger side. Dealership said thet could fix it and ordered part. When I picked the car up they said it can't be fixed and that it is normal for that car. I actually think it's worse now than when I took it in.
Gurgling sound on 2007 Lincoln Town Car
its your heater modulus, i had the same problem. Tell them to replace both L & R side.
Generally a gurgling sound from your dashboard area is caused by bubbles or air getting in to your coolant which can be heard from your heater core. Does your car use any coolant? Does it ever run too warm? Check the reservoir and make sure. If it does use or leak coolant , is your car still within warranty, that is, is it past the 3 yr/36,000 mile range? Bubbles in your coolant can be a troubling situation, in that there could be a leaking gasket in your engine, either a head gasket or intake manifold gasket etc. I would stay on this situation until it is fully resolved.