Cessna 182S Pilot Operating Handbook page 185

SECTION 7 CESSNA
MODEL 182S AIRPLANE & SYSTEMS DESCRIPTION
Oil pressure signals are generated from a pressure
line/transducer combination. An oil pressure line is routed from the
upper front of the engine case to the rear engine baffle. At the
baffle, the oil pressure line is connected to a transducer. This
transducer produces an electrical signal which translates into a
pressure reading at the instrument panel gauge .
Oil temperature signals are generated from a resistance-type
probe located in the accessory case. As oil temperature changes,
the probe resistance changes. Th is resi stance is translated into oil
temperature readings on the cockpit indicator.
In addition, a separate low oil pressure indication is provided
through the panel annunciator. This annunciator is wired to a
pressure switch located on the rear of the engine accessory case.
When oil pressure is below 20 PSI, the switch grounds and
completes the annunciator circuit, illuminating the red OIL PRESS
light. When pressure exceeds 20 PSI, the ground is removed and
the OIL PRESS light extingu ishes.
NOTE
The low oil pressure switch is also wired into the Hobbs
(hour) meter. When pressure exceeds 20 PS I, a ground is
supplied to the hour meter, completing the hour meter
circuit.
I The EGT/CHT indicator, located on the left side of the instrument
panel, is activated by electrical signals originating in the engine
compartment. Markings for the exhaust gas temperature portion of
Ithe indicator are in 2soF increments, with no range markings or red
lines. Marking for the cylinder head temperature portion of the
lindicator are in SO°F increments, with numbers at 200°F, 300°F,
400°F and SOQoF. Normal operating temperatures (green arc) for
Ithe CHT indicator are 200°F to SOO°F, with red line at SOO°F.
EGT signals are generated from a thermocouple probe in the
exhaust system. This probe allows a small amount of current to flow
through it, and as temperature across the probe changes, so does
current flow. This change in current lIow registers on the indicator
as a change in temperature. Although the EGT gauge contains no
red lines or operating range marks, it is useful in establish ing peak
EGT and cruise EGT reference points for leaning the mixture.
7-20 Nov
1SI00