Signs of a leaking heater core

The heater core is a small radiator behind the dashboard. Hot engine coolant flows through it and the fan blows air across it to warm the cabin and clear the windscreen. When it starts to leak, these are the usual signs:

1. A sweet smell inside the car, especially with the heater on.
2. A foggy or greasy film on the inside of the windscreen that keeps coming back.
3. Damp or wet carpet, usually on the passenger side floor.
4. Coolant level dropping with no leak visible under the bonnet.
5. Little or no heat from the vents, or the engine running hot.

What to do next

Have the cooling system checked to confirm the heater core is the source. Replacing it normally means working behind the dashboard, so it is a job for your mechanic or radiator specialist. Autoheat supplies the replacement core — including short-cut versions designed for faster fitting that allow the dash to remain in the vehicle.

Finding the right replacement

Search our catalogue by make and model, the OE number on your old core, or an Autoheat IHC part number — or browse heater cores by make. Not sure? Text a photo of your old core to 0483 930 398 or call 02 6281 2850 and we'll identify it for you.

Common questions

What does a leaking heater core smell like?

Usually a sweet, syrupy smell inside the cabin, strongest when the heater or demister is running. That is engine coolant evaporating from the core.

Why does my windscreen fog up with a greasy film?

Coolant vapour from a leaking heater core condenses on the inside of the glass and leaves an oily film that is hard to wipe clear.

Can a heater core leak make the carpet wet?

Yes. The heater core sits behind the dashboard, so a leak usually shows up as damp carpet on the passenger side floor.

Is it safe to keep driving with a leaking heater core?

A leaking core lets coolant escape, which can lead to the engine overheating, and a fogged windscreen reduces visibility. Have it checked as soon as you can.