Does anyone know why a radiator would clang? Possibly a silly question, but one of our radiators in our passage is making a clanging noise while it is on. It occurs every so often. I had a look at it, and there is no metal on metal other than the hinge that is holding it to the wall, so I don’t understand why it would be making such a noise. Typical isn’t it. One of our good radiators is outside waiting to be dumped!

Note added 28/12/2008: I see this post gets a lot of hits, so I did a little research and found the following causes and affects.
The radiators are not the problem, so don’t go out and replace them.¬† You can find more information in a PDF called GAS FORMATION AND NOISE IN HEAT INSTALLATIONS.

  • excessive speed of the water producing a noise similar to an open stopcock.
  • air presence in the upper side of the radiator with the particular noise of flowing water, due to the incomplete filling of the radiator.
  • the circulation pump of the fluid working outside recommended limits causing resonance especially in the radiators.
  • wall brackets out of alignment causing noises similar to metallic blows during the heating or cooling phase due to badly compensated thermal expansion. The noise is transferred from the pipes onto the heating appliances with the typical ‘ticking’ reappearing at every thermal variation. The copper pipes with insulation are noise free.


  • The ground noise due to water speed and turbulence on entering the radiator can be eliminated by working on the regulation valve to correct the water delivery as projected. However if the noise continues, it is possible to solve the problem with a diam. 18 mm diverter directly connected to the entrance valve of the radiator in order to convey the
    water to the next element of the radiator.
  • The noise caused by the air presence in the radiator can be eliminated by installing a floating automatic air vent valve.
  • The resonance of the circulation pump disappears by adjusting the pump head or revolutions (see instruction booklet). In some cases it is necessary to install an expansion joint between pump and pipes.
  • The noise of thermal expansion can be eliminated by covering the bracket with a rubber sheath.
  • To avoid noise in expanding pipes, it is necessary to use pipes fitted with insulating sleeves.

Note added 25/02/2007
Take a look at Brownstoner’s web site for some valid causes of clanging radiators, and possible solutions. There is a mention of a book you can buy that tells you what to do in order to fix the problem (without getting the professionals in)… The book is called, “We Got Steam Heat, A homeowners Guide to Peaceful Coexistence” by Dan Holohan.