Chevrolet 2002 Cavalier Owner's Manual page 86

Engine Coolant Heater (If Equipped)
2.4L L4 (LD9) and 2.2L L4 ECOTEC (L61) Engine
In very cold weather, 0 _ F ( 18 _ C) or colder, the engine
-
2.2L L4 (LN2) Engine
coolant heater can help. You'll get easier starting and
-
better fuel economy during engine warm up. Usually,
the coolant heater should be plugged in a minimum of
four hours prior to starting your vehicle. At temperatures
above 32 _ F (0 _ C), use of the coolant heater is
not required.
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