Yes you can get leak sealing products, but your'e better locating the leak.
Take all rad caps off, put tissue under each valve,check all fittings visible etc.
I've taken the caps off all the radiators and can't see anything obvious. We have obvious signs of leaks from the ceiling and the downstairs pipework is under the flooring. Which I suspect is going to be a big job to check
Are Vent points the same place I bleed the rad from?
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