Textron 172R180HP, Pilot Operating Handbook

Page: 209 / 396

CESSNA
MODEL 172R (180 HP)
SECTION 7
AIRPLANE & SYSTEMS DESCRIPTION
An exhaust gas temperature (EGT) indicator is located on the
left instrument panel as part of the EGT/Fuel Flow indicator. Al
thermocouple probe in the tailpipe measures exhaust gas
temperature and transmits it to the indicator. The indicator serves as
a visual aid to help the pilot adjust mixture through monitoring of
exhaust gas temperature. Exhaust gas temperature varies with fuel
to air ratio, power, and RPM. However, the difference between the
peak EGT and the EGT at the cruise mixture setting is essentially
constant, and this provides a useful leaning aid.
NEW ENGINE BREAK-IN AND OPERATION
I
The engine run-in was accomplished at the factory and is readyl •
for the full range of use. It is, however, suggested that cruising be
accomplished at 75% power as much as practicable until a total of
50 hours has accumulated or oil consumption has stabilized. This
l
will ensure proper seating of the piston rings.
ENGINE LUBRICATION SYSTEM
,,
The engine utilizes a full pressure, wet sump type lubrication
system with aviation grade oil used as the lubricant. The capacity of
the engine sump (located on the bottom of the engine) is eight
quarts. Oil is drawn from the sump through an oil suction strainer
screen into the engine-driven oil pump. From the pump, oil is
routedl
to a bypass valve. If the oil is cold, the bypass valve allows the oil to
bypass the oil cooler and go directly from the pump to the full flow
oil filter. If the oil is hot, the bypass valve routes the oil out of the
accessory housing and into a flexible hose leading to the oil cooler
on the right, rear engine baffle. Pressure oil from the cooler returns
to the accessory housing where it passes through the full flow oil
filter. The filter oil then enters a pressure relief valve which
regulates engine oil pressure by allowing excessive oil to return to
the sump while the balance of the oil is circulated to various engine
parts for lubrication. Residual oil is returned to the sump by gravity
flow.
An oil filler cap/oil dipstick is located at the right rear of the
engine. The filler cap/ dipstick is accessible through an access door
on the top right side of the engine cowling. The engine should not
be operated on less than five quarts of oil. For extended flight, fill to
eight quarts (dipstick indication only). For engine oil grade and
specifications, refer to Section 8 of this handbook.
Oct 4/01
7-21