How to Repair a Leaking Steam Radiator Vent

What You'll Need
Radiator bleeding key
Cloth rag
Air valve
Teflon tape
Sand paper
Metal patching compound
Mirror and flashlight

A radiator vent is the opening from which the radiator projects heated air into a room of your home. It is very important to keep these vents clean and free of obstruction, as they will otherwise prevent the furnace and the radiator from being able to fully accomplish their tasks. One of the more common problems that can occur for a steam radiator vent is for it to begin to leak. This can happen for a number of reasons, so to be sure that the radiator is working properly and that the leak will not continue, it's necessary to remedy the problem.

Step 1 -- Bleed the Radiator

One of the potential causes for a radiator vent leak is a build up of excess air or water in the radiator. With steam passing through the radiator system, condensation can build up as liquid water in the radiator. If you notice your radiator vent leaking, it's a good idea to first bleed the radiator. Open the front cover of the radiator and locate the air vent valve. Look for the bleed key slot on the valve. Turn the thermostat down and allow the radiator to cool off. Then, place a bowl underneath the air vent valve and a cloth rag around the valve. Turn the bleed key about a half turn counterclockwise to open it up.

Allow the radiator to hiss as excess gas and water are expelled from inside of it. It's not uncommon for water to leak out at this time as well, so be sure to catch it in the bowl. When the radiator has stopped hissing, turn the bleed key back to the initial position.

Step 2 -- Determine the Source of the Leak

While the radiator cover is open, examine it for signs of the source of the leak. Use the mirror and flashlight to survey the inside of the radiator. Use sand paper to sand off any rust or other damage that may have occurred to the radiator or the vent as a result of the leak.

Step 3 -- Mix Up Patching Compound

Use a metal patching compound to fix the leak. Begin by mixing up the patching compound according to the manufacturer's instructions. Then, apply a small amount of the compound to the particular area that is suffering from the leak. As soon as you do, cover the entire area with a towel or a cloth rag and allow the metal patching compound to dry. Most patching compounds take about a full day to set and dry. Check over the compound after it has had a chance to dry, and check for further signs of a leak.

Turn the thermostat back up and operate the radiator again. Check again for signs of a leak to be sure that the patching compound worked properly.