First: make it safe
- Turn off your heating system (boiler).
- Let the radiator cool completely.
- Place a towel or container under the leak.
Common leak points & fixes
1. Valve connection (where pipe meets radiator)
- Try gently tightening the nut with a spanner.
- If it still leaks, you may need to wrap the threads with PTFE tape (plumber’s tape) and re-tighten.
2. Bleed valve (small screw at the top)
- Tighten it slightly with a radiator key.
- If it’s worn or still leaking, the valve may need replacing (they’re inexpensive).
3. Radiator body (rust hole or crack)
- This is trickier. You can use a temporary fix like epoxy putty or a radiator leak sealant.
- Realistically, a corroded radiator usually needs replacing.
4. Pipe joints
- Tighten fittings carefully.
- Persistent leaks often mean the joint needs resealing or replacing.
Temporary fixes (quick stop)
- Epoxy putty (like plumber’s repair putty) can seal small holes.
- Leak-seal additives can be added to the heating system, but they’re more of a short-term solution.
When to call a professional
- If the leak is from the radiator panel itself
- If tightening doesn’t work
- If you’re unsure about draining the system
A heating engineer can properly drain, repair, or replace the radiator safely.