A friend has one a 2002 4 cyl I think and it weeps from the head gasket- dealer says the factory fix (per a service bulletin) is a bottle of coolant stop leak.
If I understand the service bulletin correctly, the fix on your friend's car is NOT simply a bottle of conditioner - but a head gasket replacement. The "bottle fix" only applies if the gasket is not yet leaking. hopefully the car is under 8 years old and less than 100k miles. I did actually use stop leak on a cavalier and it stopped the head gasket leak for the next few years that I had it