I took car to the stealer for an electrical issue that I was not able to resolve. I got into my car after them having it all day and noticed the engine was not cold, its 0 deg C here

. I thought that was strange. I was on my way home when I changed my display to where it shows me how long the car has been on and the MPG info. I noticed that they had the car idling for about an hour and a half

. What would they possible need to be doing with the engine on that long. The original problem was with the radio!!! More importantly, what is the possible damage they may have caused by leaving it so long??????