I have it too, i dont believe so many of our head gaskets could be going. mine uses a bit of water but only a pint or so in the last 6000 miles, it only does it when cold. the heads never been off and the cars only done 35 k. it must be the heater matrix, altho i should get it pressurised to check
dont think it could be an airlock, cos i was told the cooling system bleeds itself of excess pressure.
i think im right in assuming its only the ecotec models which gargle? ive heard my mates cars do it too.

strange you say that because i have the same noise when i start my car, but i have a suspision that this might be because of a leak i may have in my coolant system... but i am not sure. get it to a garage if i were u!

I WOULD GET IT PRESSURE TESTED, I HAVE BEEN READING ABOUT PEOPLE WITH SIMILAR PROBLEM AND THEY HAVE HAD THE HEAD GASKET GOING SHORTLY AFTER, COULD BE AIRLOCKS IN THE SYSTEM.

I am getting a build up of water in the drivers foot well and possibly the rear footwell. I can hear water running when i start the car so i think it might be the heater matrix. Has this happened to anyone and how did they fix it and also does anyone have any other idea's on what it could be? I also just fitted some lexus lights and think maybe they need tightened but i dont think they would let in as much water and wouldnt explain the running water noise when its dry outside. All help welcome. Cheers