The water pump and/or the plastic side tanks on the radiator may leak causing a loss of coolant. The engine may overheat due to coolant loss. Continued coolant loss after external leaks have been repaired could indicate a blown head gasket.
Car Problem Reports
Cadillac DTS Coolant Leaks From Water Pump and Radiator
Cadillac DTS Problem
Average Mileage: 57,500 mi (35,000 mi - 80,000 mi)
Random overheating at idle, guage would go from mid point to red very quickly - too quick to be real. Probably reading air in the system. Found coolant level low, so filled to appropriate level. Overheated again in driveway a week later and noticed leakage evidence under water pump. Replaced water pump and filled coolant. 2 months later overheating starts again, always at idle. This time noticed coolant under front of car, radiator appears to be source. Plan to replace radiator this weekend.