1994 Chevrolet Suburban Owner's Manual - Page 141

Heater Output Engine Coolant Heater If your vehicle has a diesel engine, it is equipped with an engine coolant heater. An engine coolant heater is optional on gas engine vehicles. You can use an engine coolant heater during initial start-up in cold weather (20" F, -8" C, or lower) to help heat thepassenger compartment faster. Because an engine coolant heater warms theengine coolant, your vehicle's heating system can provide some heat as soon as you start the engine. The use of an engine coolant heater also reduces the timeit takes for the engine to reach normal operating temperature, andshortens the time it takes the heater to reach full output. For more information, See "Engine Coolant Heater" in the Index. Diesel Engine If you idle your diesel engine for a long time when it's cold outside, your heater may blow out cool air. This is normal. When you increase theengine speed, your heater should blowout warmer air. Ifit doesn't, your coolant level may be low.See "Engine Coolant" in the Index to find out how to check your coolant level. Heating System (Without Air Conditioning) If your vehicle does not have air conditioning, this is what your heating system will look like. 3-4