A leaking radiator can cause serious water damage if ignored. Most leaks are minor and fixable without a plumber.
What Causes a Radiator to Leak? The most common causes are a loose bleed valve, a worn gland nut, or corrosion at the pipe connection.
What You’ll Need A radiator bleed key, PTFE tape, adjustable wrench, and radiator sealant.
Step 1: Identify the Leak Dry the radiator completely and run the heating. Watch carefully to find the exact source of the leak.
Step 2: Tighten the Bleed Valve Use a radiator bleed key to gently tighten the bleed valve. Don’t overtighten — just snug.
Step 3: Tighten the Gland Nut The gland nut is at the base of the valve. Tighten it half a turn with a wrench.
Step 4: Apply PTFE Tape If the leak is at a pipe connection, turn off the heating, drain slightly, and wrap PTFE tape around the thread before reconnecting.
Step 5: Use Radiator Sealant For pinhole leaks caused by corrosion, pour radiator sealant directly into the system. It seals small leaks from the inside.