2008 Cadillac STS Owner's Manual - Page 103

Engine Coolant Heater The engine coolant heater, if available, can help in cold weather conditions at or below 0°F (−18°C) for easier starting and better fuel economy during engine warm-up. Plug in the coolant heater at least four hours before starting your vehicle. An internal thermostat in the plug-end of the cord may exist which will prevent engine coolant heater operation at temperatures above 0°F (−18°C). {CAUTION: Plugging the cord into an ungrounded outlet could cause an electrical shock. Also, the wrong kind of extension cord could overheat and cause a fire. You could be seriously injured. Plug the cord into a properly grounded three-prong 110-volt AC outlet. If the cord will not reach, use a heavy-duty three-prong extension cord rated for at least 15 amps. 5. Before starting the engine, be sure to unplug and store the cord as it was before to keep it away from moving engine parts. If you do not, it could be damaged. How long should you keep the coolant heater plugged in? The answer depends on the outside temperature, the kind of oil you have, and some other things. Instead of trying to list everything here, we ask that you contact your dealer in the area where you will be parking your vehicle. The dealer can give you the best advice for that particular area. To Use the Engine Coolant Heater 1. Turn off the engine. 2. Open the hood and unwrap the electrical cord. For the 3.6L V6 and 4.4L V8 engine, the cord is located in the front of the engine compartment, on the passenger's side of the vehicle. For the 4.6L V8 engine, the cord is located in the engine compartment on the driver's side of the vehicle near the inner fender and above the strut. 3. You must remove the plastic cap to access the plug. 4. Plug it into a normal, grounded 110-volt AC outlet. 2-31