Chevrolet 10 Series 1968, Service Manual, Page: 405 / 713

ENGINE FUEL 6M-12
F ig . 5 A —C le a n in g Polyurethane Band
4. Check the paper element as previously outlined
(without the polyurethane band).
Install the polyurethane band around the paper ele­
ment and install the air cleaner element.
Cleaning Oil Bath Cleaner
1. At every engine oil change period, remove the air
cleaner assembly.
2. Remove cover and filter element assembly.
3. Empty oil out of cleaner and clean out all oil and
accumulated dirt.
4. Wash body with cleaning solvent and wipe dry.
5. Wash filter element by sloshing up and down in
cleaning solvent.
6. Dry filter unit with an air hose or let stand until dry.
7. F ill body of cleaner to full mark with SAE 50 engine
oil. If expected temperatures are to be consistently
below freezing, use SAE 20 engine oil.
8. Assemble filter and cover assembly to body of
cleaner.
9. Install cleaner, making sure it fits tight and is set
down securely.
CHECKING THERMOSTATIC ELEMENT (366 and 427)
Before replacing the thermostatic element, check the
operation of the air valve to see that it works freely and
does not bind. Replace any bent or broken air valve
components and before making the following check of the
thermostatic element.
The air valve thermostatic element may be easily
checked for proper operation whenever the cover is re­
moved for regularly scheduled element cleaning. At this
time, immerse the cover (far enough to cover the ther­
mostat pellet) in water of less than 80°F. The valve
should remain closed. Gradually raise temperature of
the water. The valve should begin to open at a water
temperature of 83°F and be fully open at a temperature of
120°F.
Thermostat Replacement
1. Remove sheet metal to air cleaner hose from the air
cleaner cover.
2. Remove the wing nut and cover.
F ig . 6 A —Thermostatic A ir V a lv e Pallet Replacement
(366 and 427)
3. Loosen the jam nut and unscrew the thermostatic
element.
4. Screw in a new thermostatic element until it just
bottoms on the push rod (with the valve held closed
by the spring). Immerse cover and element in water
of 8 3 °F for two to three minutes, then screw the ele­
ment in further until the cover air valve just begins
to open. Tighten jam nut. Raise water temperature.
Valve should be fully open at 120°F.
5. Replace the cover and wing nut, and the sheet metal
to air cleaner cover hose.
THERMOSTATICALLY CONTROLLED AIR CLEANER
This system is designed to improve carburetor oper­
ation and engine warm-up characteristics. It achieves
this by keeping the air entering the carburetor at a
temperature of at least 100°F or more.
The thermostatic air cleaner system includes a tem­
perature sensor, a vacuum motor, and control damper
assembly mounted in the air cleaner, vacuum control
hoses, manifold heat stove and connecting pipes. The
vacuum motor is controlled by the temperature sensor.
The vacuum motor operates the air control damper
assembly to regulate the flow of hot air and under hood
air to carburetor. The hot air is obtained from the heat
stove on the exhaust manifold.
Inspection
V isual
1. Check for proper and secure connections of heat
pipe and hoses.
2. Check for kinked or deteriorated hoses. Repair or
replace as required.
CHEVROLET TRUCK SERVICE MANUAL