How to Fix a Leaking Radiator - A step by step guide

There are few things that are more annoying than finding a wet carpet or wet patch. Finding that wet patch at the bottom of a radiator is definitely up there. If this is the case, then it may be obvious that you probably have a radiator leak. In terms of radiator problems that you might run into, a leaky radiator is one of the more annoying. It is an issue that you need to deal with relatively quickly and it may not be cheap. If you find yourself in this situation, we can help. Follow our guide below on how to fix a leaking radiator.

Where is the radiator leak coming from?

Water leaks are serious because they can do quite a lot of damage to floors and furnishings. There are different types of radiators installed on most central heating systems now.  The first thing you need to identify is where the leak is coming from.  The two places you can spring a leak will either be the radiator panels themselves or the radiator valves at the end of the radiator. In the case of a leaking radiator valve it will leak from where it enters the radiator or another joint on the two nuts. The water can run down the water pipe and no be entirely visible for quite a long time. If the valve is damaged it may also leak from the main body of the valve. Radiator pipes tend not to leak unless they are split, broken or have a pinhole leak, but this is unlikely to just drip. You'd certainly notice a problem with the pipe itself. Here you are much more likely to experience a leaking pipe joint, either near or close to where the pipes connect to the radiator valve. Another area where a radiator may be leaking is at the bleed valve if this is not done up tightly. With a bleed key, this is a ten second job to fix that you can sort on your own.  

How to fix the radiator valve when leaking

If you have identified the radiator valve to be the source of the leak and leaking water this could be due to the compression in the valve expanding due to the heat. This means you may only see the leak when the system is hot. If the valve is leaking from the valve body or the stem in the middle, this means that the valve has failed and you should call a plumber since you will need a new valve. If you choose to tighten up the brass insert body, you could damage it further. You can buy a replacement valve here at Column Rads and then we recommend calling a plumber. This is only a small job and will not cost much money.  

How to fix the radiator valve nuts when leaking

If you have identified the nuts as the cause of the leak this could also be due to expansion and they simply need tightening up. This can occur on both radiator valves including the lockshield valve. Have a look at our online video to see the procedure to follow for tightening up the nuts. If this is the cause of your radiator leak then you have run into some good luck since this is normally quite a quick fix. Do ensure that the radiator is turned off before you tackle the job since it may contain hot water. If the water leak is very bad and there is too much water to mop up you might need to consider switching off the water supply and the main supply valve.  

How to fix the radiator yourself.

If the radiator panels are leaking then the steel skin has failed which is unfortunately means the radiator will need replacing. This will be due to corrosion or the welding points becoming loose. Below are some temporary fixes while you order a replacement radiator: If the radiator panels are leaking then the steel skin has failed which is unfortunately means the radiator will need replacing. This will be due to corrosion or the welding points becoming loose. Below are some temporary fixes while you order a replacement radiator:

Fixing Pin Holes

There are products on the market like the F4 leak sealer from Fernox which is added to a system to block any leaks internally. This is fine if the hole is a pin prick but will not work on large holes and is only a temporary fix. Remember to read the instructions or the products FAQ for how to use it effectively.  

Fixing Small Holes

You can also use LSX jointing compound and leak sealer from Fernox which is an external leak sealer that again, is a temporary fix and only suitable for small holes. These plastic resin sealants can sometimes work on these leaks.  

Fixing Medium to Large Holes

If you find a meduim to large hole, your radiator is beyond temporary repair. You will need to isolate it by shutting off the radiator valves. This will stop the water circulating, but you will still have all the water left inside. This will need to be captured in a bucket if you cannot plug the hole. Once isolated, you can drain the radiator down by cracking the nuts on the rad valves. This can be an awkward job and please be prepared with towels and buckets before you start. Our partner site offers a great new product, PlumbPads which are like a big nappy to soak up any water and hold it in a disposable pad.  

Buying a new radiator

If you need to replace a radiator remember not to oversize it as newer radiators are a lot more efficient now than older panel radiators.

• When replacing a single panel, no connector radiator a new single convector (T11/Single Premium) will give you twice as much heat.  In theory you could half your current radiator in size (as long as you can adjust the pipework accordingly.)

• A double panel radiator will give you the same output as a single convector. A double panel, single convector will give you a third more output. A panel or convector is the equivalent surface area and a convector fin uses its corrugated form to increase output.

Column Rads stocks and supplies a huge range of Revive radiators which include, steel panel, column and towel rails. If you need help choosing the right radiator then please contact your our experts and they will be happy to help.