On many vehicles, the leak is in the plastic
Cooling systems used to be mostly metal. Many built in the last couple of decades are not. Radiators commonly have plastic tanks crimped onto an aluminum core, and thermostat housings, water outlets, hose connectors and overflow tanks are often plastic too.
Those parts are light and they work well for years. They also age in a particular way. Plastic that has been heated and cooled thousands of times becomes brittle, and the places where plastic meets metal, or where two pieces join, are where seepage starts. A housing can crack along a seam. A radiator can begin to weep where the tank meets the core.
The early signs are rarely a puddle. They are residue.
What to look for
With the engine cold, look along the top and sides of the radiator, around the thermostat housing where the upper hose connects to the engine, and at any plastic fittings on the hoses.
- Dried crust in white, green, orange or pink along a seam or joint. Coolant leaves a trace as it evaporates.
- Dampness or staining below a joint.
- A faint sweet smell under the hood after a drive.
- A level that drops slowly over weeks.
Do not press or flex old plastic fittings to test them. A part that is already brittle can break in your hand.
Why it is worth catching early
A plastic seam that weeps tends to get worse rather than stabilize, and a cracked housing can go from seep to sudden failure on a hot drive. Replaced before that happens, it is a contained job. Replaced after an overheat, it can be one part of a much larger one.
When a radiator or housing is replaced, ask about the hoses and clamps at the same joints, since they have aged alongside it.
A fault that turns out to be the engine itself is engine repair, at the same address, and an oil change visit is a convenient time to have someone look under the hood. The national cooling system page covers what to do if the gauge goes into the red.
Other stores nearby
Joplin and Osage Beach also offer cooling system service.
About this store
The Springfield store runs nineteen services and is managed by Steve Richardson.
See the national cooling system page for all 33 locations.