Mercedes 1997 C180 overheating at idle

Hi , I have just bought a Mercedes 1997 C180 which has done 69k miles. I drove it for about 10 miles without any problems but when i went to get the car washed, i left the car running for about 15 minutes, i realized that the temp gauge was almost hitting the 120 degrees heat mark but once i started to drive it again the temp gauge was going down a little bit. Is that a problem or is it normal?”

No modern day car is really made to sit and idle for fifteen minutes just sitting, especially if the AC is on. The catalytic converters will get hot, and the cooling system will be overtaxed. That said, you should have your cooling fans checked to see if they are all coming on correctly when the engine does get warmer. Because if the car runs perfect at highway speeds but runs a lot warmer when in stop and go traffice, then the cooling fans would be suspect (as you don’t need any extra wind through the radiator when you already have 60 MPH winds when driving that speed.)