gurgling water noise from glove box?

The heater core is behind the glove box. There is air in the cooling system causing the gurgling sound. The cooling system should be topped off and inspected for any leaks. With all the air out of the cooling system there should be no gurgling noise from behind the glove box.

Sorry this isn't an answer but another question related to yours. I get an intermittent leak that soaks the footwell of the passenger side. Wonder if it's related to the same problem.

Sounds like your heater core has a leak, its located behind the glove box. When a heater core leaks it will soak the carpet on the passenger side.