One problem related to vehicle overheat has been reported for the 1999 Saturn SL1. The most recently reported issues are listed below.
While driving at 30 mph engine was very loud, and the check engine light came on. Consumer took vehicle to a mechanic, who found no oil in the engine. Three quarts were added, and the check engine light went out. Two days later, check engine light blinked, and the temperature gauge was indicating that the vehicle was over heating. The consumer added coolant, but driving under three miles vehicle overheated again. The vehicle was taken back to the mechanic, who informed the consumer that oil and coolant were mixing together in the engine. A new engine was needed.