Gurgling noise from heater hose area under dash?

[MiCaddy]

There is a "gurgling" noise coming from the area of the heater hose under the dash when accelerating at lower speeds. Reminds me of our stomach at times when it is not happy........I recently tried to fit a new thermostat but must have put it in upside down as there was no flow so I left it out. Could this be the cause? Which way does the "crown" of the thermostat face, up or down?

[BOGANV8]

The car requires the themostat to control the fuel mixture when cold & hot so put it back in otherwise the car will run to rich as it thinks the car is cold...

The crown of the themostat faces up , the bulk of the themostat ie the spring part faces towards the bottomand it sits in the groove make sure it sits in the groove otherwise when you bolt the housing up you can crack it....

The gurgliing could be that you didnt get all the air bleed out of the system.....

[Not_An_Abba_Fan]

+1 for bleeding the system correctly.

[MiCaddy]

Thanks for the advice. Appreciated.