I have a 05 Impala LS with the 3.8 engine and I have added about a quart of coolant in the last 6,000 miles. That seems like more than normal to me. Does anyone have any experience with this? It only has 16,000 miles.

John

 

Have you checked it before? Or had any work done to your cooling system? If so it could have been air trapped in the system, although that seem like a lot.
If not check to see if it has any wet spots on the hoses when it is both cold and hot. (they tend to leak more after heating up). If you don't see any check your oil, if it is milky or watery you more than likely have a blown head gasket, or the head itself is not tight.