2010 Buick Enclave Owner's Manual - Page 295

Driving and Operating When towing at high altitude on steep uphill grades, engine coolant will boil at a lower temperature than at normal altitudes. If the engine is turned off immediately after towing at high altitude on steep uphill grades, the vehicle may show signs similar to engine overheating. To avoid this, let the engine run while parked, preferably on level ground, with the transmission in P (Park) for a few minutes before turning the engine off. If the overheat warning comes on, see Engine Overheating on page 10‑17. On a long uphill grade, shift down and reduce the vehicle speed to around 88 km/h (55 mph) to reduce the possibility of the engine and the transmission overheating. 9-51 Parking on Hills If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the wheels into the curb if facing downhill or into traffic if facing uphill. 2. Have someone place chocks under the trailer wheels. 3. When the wheel chocks are in place, release the brake pedal until the chocks absorb the load. 4. Reapply the brake pedal. Then apply the parking brake and shift into P (Park). 5. Release the brake pedal. { WARNING Parking the vehicle on a hill with the trailer attached can be dangerous. If something goes wrong, the rig could start to move. People can be injured, and both the vehicle and the trailer can be damaged. When possible, always park the rig on a flat surface.