If it has a sweet anti freeze smell to it, then a head gasket is starting to go.
If this is the case and the car is not overheating, I hate suggesting this but you could put some head gasket sealer into the cooling system, something like Red Devil. Read and follow the instructions to the "T" if you use this kind of stuff.
Looking for a Used Cavalier in your area?
CarGurus has 31 nationwide Cavalier listings and the tools to find you a great deal.
Search Chevrolet Cavalier Questions
Chevrolet Cavalier Experts