Why does my Swift’s radiator leak only when the engine is hot?

Home > Gari Forums > Suzuki Forums > Suzuki Swift Forums > Suzuki Swift Radiator Leaks Forums

Why does my Swift’s radiator leak only when the engine is hot?

I’ve noticed that my 2012 Swift leaks coolant only after I drive for a while and the engine heats up. When the engine is cold, there’s no visible leak. Could this be a crack that expands with heat o r a pressure-related issue?

Gari Specialist asked on 03 May 2025 14:25:07 pm

1 Answer

32 views |

Gari Master - on 03 May 2025 15:09:09 pm

If your radiator leaks only when hot, it’s likely due to thermal expansion. When the engine warms up:

Coolant pressure increases significantly due to expansion.

Small cracks o r weak seals may only leak under pressure.

A faulty radiator cap can also cause coolant to overflow o r leak during heating cycles.

Diagnosis:

Check the radiator cap’s pressure rating and seal.

Perform a cooling system pressure test to detect leaks.

Inspect radiator sides and hose joints immediately after a drive while the system is still pressurized.