Cooling System Issue, Sticky hoses Options

[kavy]

Guys, i've noticed something rather peculiar with the cooling system of my car from about a week.The coolant level drops by about 100ml from time to time and with this, the radiator hoses become sucked with pressure developed within the cooling system and released on opening of the radiator cap.There are no visible leaks whatsoever and the pressure is normal upon testing by a friend.Also refilled coolant after getting the whole system flushed making sure to burp it for removal of any air bubbles. Could it be an issue with the thermostat ???Are the hoses reusable ???And is it that my radiators time has expired ???lol. I'm lost.

[kavy]

Ok,for the thermostat,i do know that the valve opening temperature is engraved on it (82 degrees celsius) but is there a specific part number available for it. I doubt its available locally so any ausi members care to give pointers on where about i can find it when i fly over for x-mas and new years??Coolant vacuum lines??Not really sure where to go about checking that..The only thing i found in the service manual are that of the pipes that circulate coolant..Help..