Symptom guide
Coolant Leaking Under Car
How to identify coolant leaks and decide whether the car is safe to drive.
Quick answer
Coolant leaks commonly come from hoses, radiator, water pump, thermostat housing, reservoir, or heater core.
Most likely causes
- Radiator leak
- Hose leak
- Water pump leak
- Thermostat housing leak
- Coolant reservoir crack
Basic driver checks
- Look for colored fluid and sweet smell.
- Check level only when cool.
- Watch temperature gauge.
- Look for dried crust near hose connections.
DIY diagnostic path
- Never open a hot radiator cap.
- Use the correct coolant type.
- Pressure testing is best for hidden leaks.
- Tow if overheating occurs.
Common mistakes
- Driving after topping up repeatedly
- Mixing incompatible coolant
- Ignoring small leaks before long trips
What to tell the mechanic
Describe leak location, coolant color, temperature behavior, and how fast the level drops.