Chevrolet DB90 Series, Service Manual

Page: 101 / 242

Sec. 6M- 95
SECTION 6M
C'ttaine fyuel Suitem
T h is group is divided into four sectio n s as shown in Index below:
Subject Page No.
A ir C lean ers ...................................................................................... 95
G asoline Engines ............................................................................... 95
53 and 71 S e r ie s D ie se l Engines .................................................103
C um m ins D ie se l E n g i n e ................................................................... 107
Ain GUoH&nA
(ALL ENGINES)
A ll inform ation in S ervice Manual ST135-70 pertaining to "AIR CLEANERS,”
p ages 6M-1 through 6M -6 is applicable to m odels covered by th is supplem ent with
the addition of the following:
A ir clean er should be inspected and ser v ic e d at in tervals sp ecified in E m ission
Control S ystem s booklet. Air clea n ers should be se r v ic e d w henever dirt becom es
v isib le in elem ent or o il. Under ad verse conditions or exten sive operation on dusty
or sandy roads unit should be cleaned every day. A ir cle a n er s on v e h ic le s operating
in dust storm a rea s should be cleaned im m ediately after such storm occu rs.
GASOLINE ENGINES
CAUTION: In addition to its function
of filtering a ir drawn into the engine
through the carburetor, the a ir cleaner
also acts as a flame a rre ste r in the event
the engine backfires. Because backfiring
may cause fire in the engine compartment
the a ir cleaner should be installed at all
tim es unless temporary removal is nec­
essary during rep air or maintenance of
the vehicle.
DIESEL ENGINES
AIR CLEANER SERVICE
INSTRUCTIONS (F ig. 1)
Some FH and DH M odels u se the vee-typ e
elem ent air clean er as shown in figure 1.
M easuring the restrictio n of the air cleaner
elem ent is the only way to te ll if it needs to be
se r v ic e d . R estriction can be m easured with a water
m anom eter, vacuum gauge, or with a perm anently
in sta lled indicator as shown in figure 1, and is
m easured at governed engine speed. When r e s t r ic ­
tion is higher than 25 inches of w ater the elem ent
should be cleaned or replaced.
To rep lace elem ent, stop engine, tilt cab, r e ­
move 6 nuts and w a sh ers, and rem ove cover. R e­
m ove retention bracket and v ee-ty p e elem ent.
IMPORTANT: When cleaning or handling be
careful to prevent elem ent from being punched or
damaged, which would allow foreign m aterial to
enter engine.
Figure 1 —A ir Cleaner (Some DH and FH M odelsI
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT