خرطوم سائل التبريد مسرّب

A coolant hose leaking at a split, a perished end or a loose clamp. Hoses harden with heat and age, so this is a wear-out failure — and the loss it causes reaches far beyond temperature, because a system that cannot hold pressure boils at a lower temperature than one that can.

Look for the residue rather than the drip. Coolant leaves a coloured crust where it has evaporated, so the stain marks the path even when nothing is wet. The ends are where they fail, at the stub where the rubber is clamped and has taken a set. Pressure-test the system cold — that finds a hose that only leaks hot and under pressure, which is most of them, and it is the test that distinguishes a hose from a matrix or a head gasket.