Repairs · 4 min read
Why is my car losing coolant?
Coolant shouldn't be consumed. If the expansion tank keeps dropping, it's going somewhere, and finding out where is the whole job.
Visible external leaks
Hoses, the radiator, the water pump, the thermostat housing and the expansion tank itself. These usually leave a trace — a crust of dried coolant, a sweet smell after a run, or drips under the car.
Leaks you won't see
Coolant can escape into the combustion chamber through a head gasket, or into the cabin through a heater matrix. The first shows as white smoke and mayonnaise-like residue under the oil cap; the second as misted windows and damp footwells.
Pressure testing
Rather than guess, the system is pressurised cold and held to see where it drops. That finds slow leaks and hairline cracks that only open up at temperature.
Why not to top up and hope
Running a car low on coolant risks overheating, and overheating risks the head gasket and the head itself. A cheap hose replaced early is a very different job from a gasket replaced late.
Bookings
Book your car into the workshop
Tell us your registration and what the car is doing. We'll come back to you to confirm a date.