We have a 1990 Buick Reatta with 57,000 miles on it which we purchased new in Cincinnati, OH. In December, we shipped the REATTA from Cincinnati to our new home in St. Thomas, US Virgin Islands. The temperatures on island are usually in the low to mid-80's year round. There are lots of hills and need for braking on island. The maximum driving speed is about 35. Normal driving speed is in the 20's. Since the car arrived, we discovered that the engine temperature tends to run high on hills, almost to the point of overheating before the front engine fan comes on. Once the fan comes on, the temperature drops down. Obviously, the car settings were intended for a more seasonal climate with higher speed driving conditions. The island mechanics aren't familiar with the vehicle. Any suggestions about what can be done to adjust/fix the problem?