sudden leaking of gasoline along fuel line
I’d get that fixed, it’s dangerous.
Known issue with Cobalts. I had the fuel lines replaced on my 2010 Cobalt about 1-1.5 years ago. They rusted out near the fuel tank, evidently water accumulates in the area of the leak. I paid about $600 to have them replaced with OEM one piece lines. Save your receipt in case Chevrolet ever has a recall.
I’m seeing a service note about the fuel line connectors for 2010 non-turbo Cobalt. Apparently o-ring seals are used, and the o-rings need to be properly lubricated for the connector to seal correctly. Presumably that was done when the vehicle was manufactured. But if later shop work required disconnecting any fuel line connectors, failing to properly lube the o-ring upon reconnection might be a contributing factor.
Lubing o-ring seals not an uncommon fuel-system thing. On my VW Rabbit, fuel injector o-rings needed to be lubed before injector insertion.
Ask your shop to determine if leak is at connector, or from fuel hose itself. Modern day fuel hose is very robust, so I expect the problem is a connector.
Pay full att’n to advice above about the danger associated with vehicle fuel leaks. This needs immediate shop attention.
If the leak is on the undercarriage beneath the rear seat on the driver’s side, it is a rusted out fuel line. NHTSA has an open investigation that is about 2 years old on this. One day they might issue a recall but I doubt it. If you want to keep the car, it will cost around $600 to have the line replaced. BTW, I’d be surprised if this isn’t your problem. There are 208 complaints registered with NHTSA on this and you can be sure that there are many more than just that number.