Radiator leaking from the body (pinhole or seam)
Check the steps below first — if you\'re not confident, get it fixed safely today.
Find a Gas Safe engineer near you →⚠️ A radiator leaking from its body (as opposed to the valves or connections) cannot be permanently repaired — the radiator must be replaced. Do not use leak sealer products as these will contaminate the heating system and block the boiler heat exchanger.
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Most likely cause & what to check
Confirm the leak is from the radiator body and not a valve or connection — dry everything with a towel and observe carefully.
Pinhole leaks in radiator panels are caused by internal corrosion from sludge (iron oxide). They will get worse over time.
As a very short-term temporary measure, you can turn off the radiator by closing both valves — the TRV fully down and the lockshield valve. Place towels or a bowl to catch any remaining drips.
Do not use radiator leak sealant products — these are the same consistency as liquid gasket and will eventually block narrow passages in the boiler heat exchanger, causing a much more expensive repair.
Call a plumber to replace the radiator. A standard single-panel radiator costs £30–£100; labour is typically £80–£150/hour. The plumber will drain the circuit, remove the old radiator, and fit the new one.
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