Antifreeze resevoir smells

Hello:

I have a 2006 Aveo that the coolant reservoir stinks, smells. The car is not overheating, and the antifreeze is almost new, since I changed timing belt and water pump recently. No antifreeze loss or leakage. Car has 101,000 miles. Any ideas what it could be? The smell comes from the driver side. I would say it smells like its overheating but its not. Cooling fans are working too.

Despite "no antifreeze loss or leakage"...

It sure sounds to me like you've got a small coolant leak somewhere. A very small one can give off that hot coolant smell.