I purchased a used 2009 Kia Picanto last year from a dealership. One evening after work the car started shuddering and making an awful noise. In the morning the car didn't even start at first instead the engine check light came on (for the first time). It shuddered all the way to the mechanic. The mechanic listened to it and one of the cylinders was missing.

When the mechanic finished taking down the engine he found corrosion around one of those little holes in the head gasket. The rest of the gasket appears to be in good condition except for that one spot. Any advice on what could have caused this?

I have had several little issues with this vehicle since I bought it (all started after the warranty period expired) but this is the worst I think and probably will be the most expensive to fix.