Symptoms
- Coolant puddle traced to a specific hose connection or along a hose's length
- Visible cracking, bulging, or sponginess when squeezing a cooled hose
- Wet or crusty residue at a hose clamp
- Coolant level drops gradually
Likely causes
- CommonCracked or degraded rubber hoseHeat cycling over years causes rubber to harden, crack, and eventually leak, especially at bends.
- CommonLoose or corroded hose clampA clamp that's loosened over time or corroded can let coolant seep out at the connection point even if the hose itself is fine.
- PossibleHose rubbing against another component causing wear-throughVibration can cause a hose to rub against a bracket or another part until it wears through at that exact spot.
What to do
- With the engine cold, squeeze each accessible coolant hose to check for sponginess, cracking, or brittleness.
- Inspect each hose clamp for tightness, rust, or visible gaps, tightening or replacing as needed.
- Follow any visible coolant trail or crusty white/colored residue back to its source along the hose.
- Check for any spot where a hose is rubbing against a bracket, pulley, or other component and reroute or protect it if so.
- Replace the specific hose (and its clamps) if confirmed as the leak source, then refill and bleed the cooling system per your owner's manual.
Tools and parts
- Screwdriver or hose clamp pliers
- Coolant funnel
Coolant hose for your vehicle (upper/lower radiator, heater hose, etc.)Search: “radiator hose”
Hose clampsSearch: “hose clamps”
When to call a pro
See a mechanic if the leaking hose is hard to access (behind other components) or if you're not confident bleeding air from the cooling system afterward.
Safety
Use caution
Only work on hoses when the engine is completely cool; hot coolant under pressure can cause serious burns.