bubbly expansion tank...oh frightened now

[leo's dad]

drove home 2 night, switched off and heard bubbing noises from the expansion tank (slightly over filled), had a wee look and yes it was bubbling...should I be worried (more than usual). i gave her a new thermostat and cap 6 months ago.....it's not often I say this but please dont mention "head"

[drunkmonkeyboy]

could be a small leak in rad or hoses. Top it up and next time its hot have a look under the bonnet and see if anythings spraying out. my top hose did this and when i changed it, it was split nearly all the way round inside!!! fingers crossed!!!