Coolant overflow bottle hose bubbling got me f'd

[87LAG]

Hey all got my vx s s2. when i pull up and turn the car off the hose between the radiator and the overflow
sounds like its bubbling or steaming up for some reason i really cant figure out i have a new cap on there and it stopped but now is back two weeks later but not as bad. the thermostat is about 12 months old 81 degrees
one from v6 performance.

any info would be good and yes the system has been bled a couple o times at the top

cheers

[Davidcoolaye]

Not an expert on cooling systems but I wouldn't be worrying too much mate, just so long as it's not running hot and the radiator cap doesn't burn you badly when you touch it after a good drive.
Make sure there's no air locks in the system and make sure there is some fluid in the overflow so it can vacuum suck it back in when it cools down. You can always put more than enough in the over flow, what it doesn't need it'll just dump when it's hot.

Also do a basic check on the whole system hoses, water pump ect for leaks or just general wear and tear. I know for a fact the top radiator hose always slowly slips off on ecotecs. So make sure its on properly. Quick check for the rad cap to see if its working, press the pressure valve in and see if it does it with a bit of force and not needing a vice to press the valve down, then pull the vacuum valve out and see if it comes out easy.
Also to be on the safe side just keep another stock thermostat around, they are like 7 bucks for a genuine one, it's worth 7 bucks to just test.
If you really want to be picky re bleed your system. Sometimes you get tiny air pockets they wont blow a rad hose off but can always just be there.
Good luck buddy hope any of these wild shots help.

[TonyJZX]

head gasket

[87LAG]

wouldn think so if head gasket u would have oil in water or visa versa u would think. and this only happens every couple of days... and has never got hot...