Chevrolet CHEVY VAN G10 SERIES Service Manual page 187

T H E R M O S TA TIC A LLY CO NTROLLED
A IR CLEANER
6
This system (Fig. 5A,
carb u retor operation and engine warm -up characteristics. It
achieves this by keeping the air entering the carb ureto r at a
tem p eratu re o f at least 100°F or more.
The therm ostatic air cleaner system includes a tem perature
sensor, a vacuum m o to r, and con trol dam per assembly
m ou n ted in the air cleaner, vacuum co ntro l hoses, m anifold
heat stove and connecting pipes. The vacuum m otor is co n ­
trolled by th e tem peratu re sensor. The vacuum m o tor operates
the air co ntrol dam per assem bly to regulate the flow o f h o t air
and u nder h o o d air to carburetor. The h o t air is obtained from
the h eat stove on the exhaust m anifold.
Inspection
Visual
1. Check for proper and secure connections o f heat pipe
and hoses.
2. Check for kinked or d eterio rated hoses. Repair or replace
as required.
Operational
1. Remove air cleaner cover and install tem perature gauge
(T ool J-22973) as close as possible to sensor (Fig.
Reinstall cover w ithout wing n u t. (T em perature
m ust be below 85°F before proceeding.)
2. With the engine " O ff," observe dam per door position
th rough snorkel opening, View A. Snorkel passage should
be open. I f n o t, check for binds in linkage.
VIEW A — ENGINE OFF
SNORKEL TUBE
CONTROL DAMPER ASSM
VIEW C-UNDERHOOD TEMPERATURE
ABOVE 128°F
SNORKEL TUBE
^VACUUM CHAMBER
LINKAGE •
AIR INLET
r
CONTROL DAMPER ASSM.
A and 7A) is designed to improve
8
DIAPHRAGM SPRING TTH]
J]|L
- J ~ —
HOT AIR PIPE
AIR BLEED VALVE OPEN
DIAPHRAGM SPRING
DIAPHRAGM
r
— i
HOT AIR PIPE
Fig. 6 A —A ir Cleaner Operation
3. S tart and idle engine. With air tem p eratu re below 8 5 °F,
snorkel passage should be closed, View B. When dam per
door begins to open snorkel passage, remove air cleaner
cover and observe therm om eter reading. It should be
betw een 8 5 °F and 115°F.
4. If dam per d o o r does not close com pletely or does n ot
open at correct tem perature, continue w ith the following
vacuum m o to r check:
a. T urn o ff engine. D isconnect diaphragm assembly
vacuum hose at sensor unit.
b. A pply at least 9 in. Hg. o f vacuum to diaphragm
assembly through the hose. This can be done by
m o u th . D am per door should com pletely
snorkel passage when vacuum is applied. I f n o t
check to see if linkage is hooked up correctly and
for a vacuum leak.
c. With vacuum applied, bend or clamp hose to trap
vacuum in diaphragm assembly (Fig. 9 A).
D am per d o o r should rem ain in position (closed
snorkel passage). If it does n o t, th ere is a vacuum
leak in diaphragm assembly. Replace diaphragm
assembly.
5. I f vacuum m o to r check is found satisfactory, replace
sensor unit.
A).
VIEW B-UNDERHOOD TEMPERATURE
BELOW 85°F
VACUUM CHAMBER^ |
SNORKEL TUBE
CONTROL DAMPER ASSM. 1 f f
VIEW D-UNDERHOOD TEMPERATURE
BETWEEN 85°F AND 128°F
VACUUM CHAMBER
SNORKEL TUBE
AIR INLET
CONTROL DAMPER ASSM.
ENG INE FUEL 6M-13
AIR BLEED VALVE
CLOSED
DIAPHRAGM SPRING J L JL TEMP. SENSING IG I T TEMP. SEN
/ 11 | [ SPRING
X
DIAPHRAGM
HOT AIR PIPE
AIR BLEED VALVE
DIAPHRAGM SPRING
TEMP. SENSING
/
SPRING
DIAPHRAGM
HOT AIR PIPE
C H E V Y V A N S H O P M A N U A L
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