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How to fix a pinhole leak in a central heating radiator

Struggling with leaks and damp spots? Check out our guide on how to fix a pinhole leak in a radiator. With step-by-step instructions, tips and prices.

Plumber repairing pinhole leak in radiatorOver time radiators can become damaged, causing water to escape which can be problematic. As such, learning how to fix a pinhole leak in a central heating radiator is a handy skill.

No matter what is causing your radiator to leak, this guide is designed to help you when fixing the issue. We will also be looking into different areas like radiators leaking from the top, small radiator leak repair, pinhole leaks in radiators and more.

Can you fix a radiator leak?

Pinhole, small and large radiator leaks can cause issues like water damage in your home. But can you fix a radiator leak yourself? Generally, the answer is yes, a radiator leak can be repaired as a DIY job. However, it’s worth noting that if your radiator is severely damaged, degraded or the hole is too large, it may be time to buy a replacement.

How to fix a pinhole leak in a central heating radiator

Pinhole leaks are usually tiny holes that form in your radiator, allowing tiny drops of water to escape. Not a huge issue, but these should be repaired quickly to prevent further damage. Usually caused by rust and corrosion, radiator pinhole leaks usually form after sludge builds up in your radiator over time.

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Fix radiator leakIf you would rather tackle the issue yourself, it’s important to know how to fix a pinhole leak in a central heating radiator. This will prevent the damage from worsening.

So, how exactly do you fix a pinhole leak in a radiator? Just follow the below instructions:

  1. Firstly, you will need to find out where the leak is coming from, this may not be immediately obvious. Look on the floor below your radiator. Any damp patches will indicate a hole in that general area. You can also completely dry the radiator and then it should be easier to see where the leak is.
  2. Turn off your water supply and drain the radiator.
  3. Top tip: Use towels and a bucket to collect any water that escapes during radiator pinhole leak repair.
  4. Completely dust, clean and dry the outside of the radiator.
  5. Use epoxy putty on the surface of your radiator over where the pinhole leak is.
  6. Allow this to dry before refilling your radiator and switching the water back on.
  7. Another way to fix a pinhole leak in a radiator is to add a leak sealer solution to your central heating water tank. This will then flow throughout the system and hopefully seal any leaks.

How to fix a radiator leak

In addition to leaks on the main body of your radiator, it’s also fairly common for your radiator valves to spring a leak. Often radiator leak repair isn’t too difficult to learn, although it’s important you do a good job to stop the leak from worsening over time.

What’s more, a small radiator leak repair is no trickier than for standard size radiators, so you can use the same fixing methods. If you are wondering how to fix a radiator leak that is coming from the valve, just use the below instructions:

  • Switch off the water supply to your radiator, then drain the radiator.
  • Unscrew the union nut using a spanner.
  • Grab a bucket and then open the bleed valve, letting any excess water drain.
  • Wrap PTFE tape around the valve tail. Do this at least 10 times.
  • Use your spanner to tighten the union nut.
  • Open the bleed valve.
  • Switch back on the water supply and refill the radiator.
  • Ensure there are no longer any leaks, then close the bleed valve.

Radiator leaking from top

There are many different points on a radiator that are prone to leaks. If your radiator is leaking from the top, this is often caused by an issue with your bleed valve. This type of radiator leak repair is generally quite simple to fix by using these steps:

  1. To start, check the issue is definitely with the bleed valve.
  2. Take a Q-tip and gently push this into the opening of the bleed valve. If it comes away wet, you have located your leak.
  3. Turn the bleed key clockwise on the bleed valve screw to tighten it.
  4. This should stop the leak.

Small radiator leakHow to fix a hole in your radiator

While pinholes are quite simple to fix, larger holes in radiators can be more problematic. If you are wondering how to repair a hole in a radiator, you will need to first assess whether it is possible. Small holes can be temporarily sealed using a leak sealer and jointing compound to cover the hole.

Medium or large holes however, cannot be temporarily fixed. Learning how to fix a bigger hole in your radiator is often impossible, unfortunately. If your radiator is badly corroded from rust, or has larger holes, you will need to buy a replacement.

How to fill holes around radiator pipes

During renovations, or when fitting a new radiator, you may end up with gaps in your walls around the pipes. This can be an issue as it gives mice an opportunity to get into your home. If you are unsure how to fill holes around radiator pipes, consider the following methods:

  • If the holes are small, you could use filler. Then once it’s dry, sand flat and paint over.
  • You could also consider using steel wool surrounded by caulk.
  • Larger holes are better filled using a lath screen, metal sheeting or even cement.
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How to fix a leaking bathroom radiator

Using towel radiators to heat a bathroom and keep your towels toasty warm is a great, efficient idea. These radiators are becoming more popular and make a good investment.  Unsurprisingly, similar to standard radiators, towel radiators can start to leak over time.

Wondering how to fix a leaking bathroom radiator? First, isolate where the leak is coming from. Check the:

  • Valves: Please see our ‘how to fix a radiator leak’ section.
  • Spindles: Can be fixed by either using a spanner to tighten the gland nut or by wrapping tape around the spindle.
  • Pipe joints: Similar to fixing the spindle, repairing pipe joints is done by tightening the joint or wrapping it with tape.
  • Radiator itself: Please see our ‘how to fix a pinhole leak in a central heating radiator’ section.

How much to fix a radiator?

If you don’t feel confident repairing your radiator yourself or you have tried the above guides and the leak is still happening, you may prefer to speak to a professional. Hiring a tradesperson to repair your radiator will guarantee a good quality job, that’s done in no time at all. Plus, for tricky repairs you will also benefit from their years of experience.

But you may be asking ‘how much to fix a radiator?’. Generally, it will cost between £70 – £170, although this will vary from job to job. If the radiator is too damaged for repair, you will need to buy a replacement. This will usually cost anything from £80 – £300 but will be less if you plan to do the work yourself.

If you are looking for a professional to either repair or replace your radiator, our network of trusted experts is a quick search away. Just enter your postcode to instantly connect with experienced professionals in your area. Or, to discover more about expert radiator replacement, please see our cost to remove or replace a radiator guide.

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