Coolant leak repair

Rubber hoses go hard and crack with age and heat, and clips can work loose. This is often the quickest and cheapest coolant leak fix.

A car radiator leak can come from corrosion inside, a stone strike at the front of the car, or a cracked plastic end tank. If your car is leaking radiator fluid, you’ll usually see drips at the very front and residue on the radiator fins.

The water pump moves coolant around the engine. When its seal wears, coolant drips from the front or side of the engine, sometimes with a whining noise. On many cars the timing belt drives the pump, so we may suggest replacing both at the same time. We’ll explain why and give you the price before doing anything.

Plastic tanks can crack, and a worn cap seal lets coolant escape as steam when the system is hot. These are small parts, but they can cause a big loss of coolant.

A damp passenger footwell, misty windows or a sweet smell inside the car can point to a leak in the heater matrix behind the dashboard.

If you’re losing coolant but can’t see a puddle, it may be leaking inside the engine. White exhaust smoke and overheating are the usual clues. This needs a proper diagnosis, so book a check rather than topping up and carrying on.

Coolant can leak from a split hose, a loose clip, the radiator, the expansion tank, the thermostat housing or the water pump. Coolant often runs along other parts before it drips, so the puddle doesn’t always sit under the faulty part. A pressure test finds the real source.

Coolant is usually green, pink, orange, blue or yellow, depending on the type your car uses. It feels slippery and smells sweet. Clear fluid with no smell is probably water from the air con, which is normal. Keep coolant away from children and pets, and don’t touch an unknown fluid.

Coolant can escape as steam through a faulty cap, drip onto hot parts and burn off, or leak inside the engine through a worn head gasket. White exhaust smoke and overheating are the warning signs. A pressure test shows where it’s going, so book a check.

Don’t drive if the temperature gauge is rising, a red warning light is on, you see steam or the coolant level is dropping fast. Stop somewhere safe, switch off and call for help. If the engine is cold and there’s no warning, give us a call first and we’ll advise you.

Look for coloured fluid near the front of the car, staining or crusty residue on the radiator, coolant that keeps needing a top-up, or overheating. Some radiator leaks only show when the engine is warm and the system is under pressure, so we may need to pressure test it to be sure.

You might see coolant loss, overheating, staining around the pump or hear a whining or grinding noise from the front of the engine. On many cars the pump sits behind other parts, so it’s hard to check yourself. Book an inspection and we’ll confirm whether the pump is the cause.

It depends on where the leak is, your car and the labour involved. A hose or clip is a small job, while a radiator or water pump takes longer and an internal engine fault can take much more work. We’ll diagnose the leak and give you a price before we start.

Not usually. A sealant might slow a tiny pinhole for a while, but it won’t repair a split hose, worn pump seal or failed head gasket, and it can block narrow channels in the radiator. Check your car handbook first, and treat sealant as a way to get home, not a repair.

You can top up once the engine is fully cool. Open the expansion tank cap slowly and fill to between MIN and MAX with the coolant type in your handbook. A top-up doesn’t fix the leak, though. If the level keeps falling, get it checked before the engine overheats.

Our Full Car Service includes a vehicle health check and a coolant top-up, so we’ll often spot the signs. If you already know you’re losing coolant, mention it when you book so we can check the cooling system properly and let you know what we find.

You can get your coolant leak checked and fixed at any of our AA Car Service Centres in Dublin, Newbridge, Cork, Sligo and Limerick. Enter your Eircode when you book online and we’ll match you to your nearest centre. All our centres are open Monday to Friday, 8am to 5pm, and there’s no upfront charge when you book a repair online.