Finding the Leak — Pressure Test First
Why We Test Before We Quote
Coolant can leak from a dozen different places: upper or lower radiator hoses, the radiator itself, the water pump, the reservoir and cap, heater core hoses, the thermostat housing, freeze plugs, or the head gasket. Some leaks are external (you can see the puddle), some are internal (coolant burns in the combustion chamber — white smoke, no external drip).
We pressurize the cooling system and let it sit. Pressure drops reveal the leak location exactly. This prevents unnecessary parts replacement and gives you an accurate repair quote.
Common Coolant Leak Locations
Hoses — Most Common, Least Expensive
Radiator hoses fail from the inside out — the inner liner deteriorates while the outside still looks fine. Upper hose failures often show as a sudden burst. Lower hose failures drip before they burst. We inspect both hoses by squeezing them — a healthy hose feels firm, not soft and mushy.
- Upper or lower radiator hose: from $99.99 installed
- Heater hose: from $89.99
Radiator
Most radiators are aluminum with plastic end tanks. The plastic-to-aluminum seams fail over time, especially after overheating events. Chico's summer heat accelerates this. A cracked end tank shows as a drip from the side of the radiator.
- Radiator replacement: from $573.18 for most vehicles
Water Pump
Water pumps have a weep hole designed to drip when the seal fails — this is intentional, so the leak is visible before coolant gets into the bearing or oil. If you see a small drip from the front of the engine near the belt, it's often the water pump weep hole.
Head Gasket — The Expensive One
Head gasket failure can be internal (coolant into the oil — tan milky residue on the dipstick), combustion chamber (white smoke from the exhaust, sweet smell, bubbling in the coolant reservoir), or external (visible leak at the head/block seam).
We use a combustion gas test (block test) to check for combustion gases in the coolant before diagnosing head gasket failure. Many vehicles set off the P0128 code (thermostat) or overheat before the head gasket actually fails — addressing the root cause early prevents the expensive repair.
Schedule Your Service in Chico, CA
Tedious Auto Repair — 2695 CA-32, Chico · Open 7 Days · (530) 826-4275