Is there anything you can pour into the water system to help you detect leaks? I just wonder if there might be some sort of dye or something available. I can hear the damn leak hissing but can't find it!

It's not for the Locost but I thought it was relevent enough to put in here!

Thanks,
James

try a plumbers shop

Had the same, today--it was the cap on the header tank (volvo) just needde tightening.