How To Stop A Leaking Radiator

We’ve all been there, you’re minding your own business when you suddenly notice that little puddle of water under the radiator. At first, you think, “Maybe I spilled something earlier?” But then you wipe it up, come back later… and it’s back. Yep. Your radiator’s sprung a leak.

A leaking radiator might not seem like a big deal at first. But left alone, it can cause water damage to floors, ruin carpets, and even put pressure on your heating system. And when it’s cold outside, the last thing you want is a heating breakdown.

So, let’s go through what you can do right now to stop (or at least slow) the leak and when it’s time to call in the professionals.

Step 1

Find the Source of the Leak

Radiators can leak from a few different places:
The valve: where you control the heat.
The bleed point: where you release trapped air.
The body/panel: less common, but usually more serious.
Pipe connections: where the radiator meets the pipework.

Grab a dry cloth or some kitchen roll and gently dab around the suspected areas. You’ll see the tissue go damp where the leak is. This is important because how you stop the leak depends on where it’s coming from.
Step 2

Turn Off Your Heating

Before you do anything else, switch off your central heating and let the radiator cool down. Hot water + hands + tools = not a good mix. Plus, working on a pressurised heating system can make a small leak worse if you’re not careful.
Step 3

Quick Fixes You Can Try Yourself

These tips aren’t meant to be permanent solutions, but they can buy you time until a plumber arrives.

If it’s leaking from the valve: Try tightening the valve gland nut gently with an adjustable spanner. Don’t overdo it a quarter-turn is plenty.
If that doesn’t help, you can sometimes wrap a little PTFE tape (plumber’s tape) around the valve threads after draining that section of the radiator.

If it’s leaking from the bleed point: Use a radiator key to make sure it’s closed properly. Sometimes they get knocked slightly open.

If it’s leaking from the pipe connections: Check the nuts that connect the radiator to the pipes. Give them a careful tighten just enough to stop drips.

If it’s leaking from the radiator body: Sadly, this usually means corrosion inside the radiator. You can put a container or towel underneath to catch drips, but a replacement is often the only long-term fix.
Step 4

Drain the Radiator

If the leak is bad and you need to slow it down, you can drain the radiator.
Place a bucket or large bowl under the valve.
Turn the valve off on both sides.
Use a spanner to loosen the nut and let the water drain into your container.
Tilt the radiator slightly to get as much water out as possible.This will stop it leaking but it also means you won’t have heating from that radiator until it’s fixed.
Step 5

Call in the Experts

Here’s the truth: even if you manage to stop the leak temporarily, it’s often a sign of a bigger problem worn seals, failing valves, corrosion, or pressure issues in your heating system.That’s where we come in. We fix leaking radiators every day, and we know exactly how to stop the leak for good, without the guesswork. We carry the right tools, the right replacement parts, and most importantly the experience to spot underlying issues before they turn into expensive disasters.

Why You Shouldn’t Ignore a Leaking Radiator

We get it life’s busy. But here’s what can happen if you leave it:

  • Water damage to floors, carpets, and even ceilings below.

  • Rust and corrosion spreading through your heating system.

  • Boiler pressure drops, meaning your heating cuts out.

  • Bigger repair bills later when small problems turn into big ones.

The earlier you deal with it, the quicker (and cheaper) it usually is.

How We Can Help

When you call us about a leaking radiator, here’s what happens:

  1. Fast response — because we know you don’t want to wait around.

  2. Full inspection — we check the radiator, valves, and pipework.

  3. On-the-spot fixes — we carry most common replacement parts in our vans.

  4. Advice for the future — including whether it’s worth repairing or replacing.

We’ve seen every kind of radiator leak you can imagine from a slow drip to a mini indoor fountain and we’ve fixed them all.

Once your radiator is fixed, ask us about a system check and flush. Over time, sludge and debris build up inside your heating system, causing corrosion and weak spots. Flushing it out and adding corrosion inhibitor can extend your radiator’s life by years.

Stopping a leaking radiator can be a simple job… or it can be the tip of the iceberg. The quick fixes above can help you limit the damage, but a permanent repair is best left to a qualified plumber.

We know how frustrating it is to deal with a leak, especially in the middle of winter. That’s why we make it easy fast call-outs, no nonsense and work done right the first time.

So if your radiator’s leaking right now, don’t wait until the puddle becomes a pond.
Call us today and we’ll get it sorted quickly, safely, and properly.

Got a leaking radiator?

Let’s get it fixed before it turns into a bigger headache.

Give us a call today and we’ll be there fast tools in hand, ready to stop the leak and get your heating back to normal. No jargon, no fuss, just good honest work that lasts.

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