Check that the leak is no where else such as the plug and air vent on the top left and right ends. You can usually spot a leak where there is a brown stain running down the radiator. If you have a leak there you will have to tighten them with either a spanner or an allen key. If that doesnt cure it you will have to turn off both valves, take out the plug or vent and remake it with PTFE tape. ps check the radiator valves for leaks too.
Plumbo
October 2011
I had a chap with a quite severely leaking boiler and advised using an internal leak sealer (fernox) which worked. Once you have followed the instructions on the bottle turn off the other radiators so the one in need of repair is the only one open. That should fix it.
ps if the radiator is leaking a lot then you may have to double up on the fernox.
Plumbo
October 2011
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