Fleetwood 1999 Discovery Parts And Service Manual page 65

Your motor home engine has been designed to conform to
applicable exhaust emission requirements. To meet these
requirements, engine operating temperatures are high. As a
result, the engine and exhaust systems radiate a great deal of .
heat.
Engine temperature gauges have been calibrated to indicate a
midrange reading as the "normal" operating temperature.
The reason for this is that many owners perceive 212 0 F as
the boiling point. However, this is not the case in an engine
with a pressurized cooling system and a coolant mixture of
glycol and water. As a motor home owner, be aware that the
gauge is intended to provide a warning of any rapid change
in engine coolant temperature from the "normal" reading of
the gauge rather than an absolute temperature reading.
Discovmy
EXHAUST
SYSTEM HEAT
ENGINE
TEMPERATURE
GAUGES