Chevrolet 10 Series 1970 Service Manual page 376

ENGINE FUEL 6M -12
AIR CLEANER ASSY.
VACUUM
DIAPHRAGM
DAMPER
DOOR
TUBE
F ig . 7a—T h e rm o s ta tic a l ly C o n tro lle d A ir C le a n e r
9. Install clean er, making sure it fits tight and is set
down secu rely.
CHECKING THERMOSTATIC
ELEMENT (3 6 6 and 4 2 7 )
B efo re replacing the therm ostatic elem ent, check the
operation of the a ir va lve to see that it works fr e e ly and
does not bind. R eplace any bent o r broken a ir va lve
components and b efore making the follow ing check o f the
therm ostatic elem ent.
The a ir valve therm ostatic
checked fo r p rop er operation whenever the c o v e r is r e ­
m oved fo r regu la rly scheduled elem ent cleaning. At this
tim e, im m e rse the c o v e r (fa r enough to c o v e r the th er­
m ostat p e lle t) in w ater o f le s s
VIEW A —ENGINE OFF
SNORKEL TUBE
LINKAGE — H
I
CONTROL DAMPER ASSM.
VIEW C -U N D E R H O O D TEMPERATURE
ABOVE 128°F
AIR BLEED VALVE OPEN
SNORKEL TUBE
AIR INLET
CONTROL DAMPER ASSM.
TEMP. S EN SIN G SPRING
FROM BASE OF CARBURETOR
(SOURCE OF INTAKE
M ANIFOLD VA CU U M )
elem ent may be ea sily
than 80°F. The va lve
DIAPHRAGM
7'J TT
^ HOT AIR PIPE
DIAPHRAGM S P R I N G ^
HOT AIR PIPE
F ig . 8a—A ir C le a n e r O p e ra tio n
should rem ain closed.
the w ater. The va lve
tem perature o f 83°F and be fu lly open at a tem perature o f
120°F.
Thermostat Replacement
1. Rem ove sheet m etal to a ir clean er hose fro m the a ir
clean er co ver.
2„ Rem ove the wing nut and c o ver.
3. Loosen the jam nut and unscrew the therm ostatic
elem ent.
4. Screw in a new therm ostatic elem ent until it just
bottoms on the push rod (with the va lve held closed
by the sprin g). Im m erse c o v er and elem ent in w ater
of 83°F fo r two to three minutes, then sc re w the e le ­
ment in further until the co ve r a ir va lve just begins
to open. Tighten jam nut. Raise w ater tem perature.
V alve should be fu lly open at 120°F.
5. Replace the co v e r and wing nut, and the sheet m etal
to a ir clean er c o v e r hose.
THERMOSTATICALLY CONTROLLED AIR CLEANER
This system is designed to im p rove ca rbu retor o p er­
ation and engine warm -up ch a ra c teris tic s . It achieves
this by keeping the a ir entering the carbu retor at a
tem peratu re o f at lea st 100°F o r m ore.
The therm ostatic a ir clean er system includes a tem ­
peratu re sensor, a vacuum m otor, and control damper
assem bly mounted in the a ir clean er, vacuum control
hoses, m anifold heat stove and connecting pipes.
vacuum m otor is con trolled by the tem perature sensor.
The vacuum m otor operates
assem bly to regulate the flow of hot a ir and under hood
a ir to carb u retor. The hot a ir is obtained fro m the heat
stove on the exhaust manifold.
VIEW B -U N D E R H O O D TEMPERATURE
BELOW 85°F
DIAPHRAGM SPRING
VACUUM CHAMBER
SNORKEL TUBE
CONTROL DAMPER ASSM. 1 f f
VIEW D -U N D E R H O O D TEMPERATURE
BETWEEN 85°F AND 128°F
DIAPHRAGM SPRING
VACUUM CHAMBER
SNORKEL TUBE
AIR INLET
CONTROL DAMPER ASSM
Gradually ra ise tem perature of
should begin to open at a w ater
the a ir con trol damper
AIR BLEED VALVE
, CLOSED
TEMP. SENSING
SPRING
DIAPHRAGM
HOT AIR PIPE
AIR BLEED VALVE
TEMP. SENSING
SPRING
HOT AIR PIPE
CHEVROLET TRUCK SERVICE MANUAL
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