Two problems related to radiator have been reported for the 2013 Chevrolet Volt. The most recently reported issues are listed below.
I live in and drive my car around southern California under normal conditions. My battery coolant radiator was hit by a small rock and leaked. This prevented charging, caused a check engine light to come on, and coolant to pool underneath my car. I towed it to a nearby chevy dealership to get the radiator replaced. Radiator damage to Volts is not uncommon. Chevrolet knows this is an issue and has issued a service bulletin covering some (but not all) Volts due to their low, vulnerable, and relatively unprotected design of the radiator. I believe Chevrolet should remedy the problem with stronger radiator shields and protectors.
Radiator failure/leaking at 67000 miles. Unknown cause. Caused car to overheat and had to be shut down to avoid further damage to electrical/battery components. Cost to repair exceeds $1500.