I've found the hole now on the back of the pipe and it feels pretty tiny. In fact it hardly leaks at all once the coolant is up to temperature ! I came to the same conclusion and have ordered some JB Waterweld which has got good reviews. Fingers crossed it does the trick as the pipes are really wedged in there
![Eek! :eek: :eek:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
The irony is the actual o-ring job was a lot simpler and quicker than I expected ......