Radiator Rattling? Here’s Why

Radiators are awesome little contraptions. They keep us nice and toasty regardless of what the outside weather is trying to do. But if you notice your radiator rattling, hissing, or making other unpleasant noises, it may be time to take a look. Luckily, this isn’t DreamyHome’s first rodeo – so we’ve got you covered. We’ve got a few fixes in store that’ll hopefully help you avoid calling in the professionals.

The most common causes of a radiator rattling are the angle it sits at, air getting trapped in the radiator, or insulation.

There’s a few good tips and tricks buried in that statement, so let’s break it down, shall we?

Why Your Radiator is Rattling

Compared to modern machinery, radiators aren’t that complicated. That is, of course, if you have a mechanical engineering degree and work on jet engines or large pieces of tech. If you, like me, are an everyday Joe, then it feels a lot more complicated than it actually is. Luckily, the fixes for a rattling radiator are actually surprisingly easy, assuming nothing has broken and needs to be replaced.

Radiator Tilt

When a steam radiator is functioning and set up properly, it actually doesn’t sit entirely level. While it may appear to be mostly level, it needs that slight tilt to help it function.

This is because the angling of your radiator helps the intake valve operate. Good ole’ gravity, back at it again! The angle allows condensed water to flow easily out of the radiator and through the intake valve without issue. If your radiator got bumped or adjusted recently, it’s entirely possible that a slight tilt may fix your issue.

If your radiator is getting noisy, start by checking it with a level. Locate your intake valve, and the radiator should be slightly tilted towards the valve. If it’s not, grab a bit of wood or something else to pop underneath it. Even something as simple as some scrap wood can help out here. You only need a tilt of roughly 5 degrees, so don’t overdo it!

Venting Radiators

Not to be confused with bleeding radiators (which we’ll get to), your radiator needs to vent. Specifically, it needs to be able to use the steam vent. Because it’s they’re metal contraptions that use water, mineral buildup is a common occurrence with radiators – even in the steam vent.

Luckily, you can fix this with a nice bowl of vinegar. Keep in mind that you’ll need to turn off your radiator, so don’t count on it keeping you warm overnight.

Start by closing the intake valve (the same valve we were helping out above) so the steam can’t enter the radiator. Now, locate and remove your radiator’s steam vent. Pop it in a bowl of vinegar (completely submerged) and let it sit overnight. This will help dissolve any mineral deposits that have built up over time, allowing them to either fall or be easily scrubbed off.

If that doesn’t work, it’s possible that you need a new steam vent. Don’t worry, they’re both cheap and easily found at most home & garden stores. Simply pop out your old one, and in goes the new! Worst case, this isn’t the cause and you have a nice, (cheap) new steam vent. One less problem down the line.


Steam regularly condenses in the pipes of your radiators. This prevents it from even reaching the radiator, and this can result in a rattling noise. This is especially common in cold environments where a major shift from warm to cold happened. The fix is to insulate your radiator’s piping.

To insulate your radiator, do the following:

  1. First, you’ll need pipe insulation. There are three choices for insulation – fibreglass pipe insulation, foam pipe insulation, or adhesive-backed insulation. You’ll want to measure the outside diameter of the water pipes in question and find insulation that’s the proper size. It’s okay to have a bit of excess insulation here, as you can just cut it down. Too little, though, and it won’t properly insulate your pipes.
    1. Measure the length of the exposed water pipes in your home. Add that length to the insulation measurement.
  2. Simply slip your new (properly measured) insulation over the pipes, peeling baack the adhesive on the back. Seal it down over the cut end of the pipe, and cut the insulation to fit smaller lengths of piping. Repeat for all sections of pipes.
  3. Add pipe wrap or insulation to elbow joints in your water piping. You can buy specialized individual units for this, or simply use insulation to thoroughly wrap it. Secure with metal foil tape.

Bleeding Radiators

Now we’ve covered this before (in the article linked at the beginning of this one), so this will be relatively short. This is a common issue that you should actually be doing regularly to prevent issues with your radiator. To bleed a radiator:

  1. Run the heat on full temp in your home for roughly ten minutes. Next, cut off your circulation pump and allow the radiators to cool off, usually no more than an hour.
  2. Locate your bleed screw on the side. Turn your bleed key or screwdriver until you hear air hissing out.
    1. Keep a bowl and some rags beneath the bleed screw, as you’ll have water coming out soon enough.
  3. Do this for between 30 seconds to a minute, until water escapes. Close the bleed screw valve, restart everything, and test your radiator.

Other Causes

Now, as I said above, there’s a lot that can go wrong here. If you’ve tried all of these solutions to no avail, I’ve got some bad news – it’s time to get help. While nobody wants to need a professional, it’s just the reality of things. Sometimes you just can’t fix things on your own. And with something that deals with so many moving parts, it’s often best to ask a professional for help.

Not only will they pinpoint the issue much more quickly than you might, but they’ll get the job done quicker than you likely could. There’s really no shame in getting a pro to take a look – it’s literally their job.

Final Thoughts

Radiators are great when they work, and annoying as possible when they develop a new sound. While new sounds are often worrying, there’s a bit of good news – it’s likely not a hard fix. Try out the above methods, beginning with ensuring your radiator is tilted properly. If that’s not the case, cleaning out the steam vent, bleeding your radiator, and insulating the pipes are generally the best next steps.

If you’ve done all of that and still have a radiator rattling, it’s likely time to call in the cavalry. A professional will troubleshoot more quickly and just do a better job than you likely could, so it makes sense. Sit back, make a drink, and watch the pros do what they do best. And maybe ask them about the issue so you can fix it yourself in the future…

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About the Author Harry Thompson

Involved in home renovations throughout his life, Harry is an expert in everything to do with home and garden DIY. In his spare time, he enjoys cooking and tending to his garden.