Chevrolet 1980 Light Duty Truck Service Manual page 23

ethylene glycol antifreeze.
Service
• Maintain cooling system freeze protection at -34°F
(-37°C) to ensure protection against corrosion and loss of
coolant from boiling. This should be done even if freezing
temperatures are not expected.
• Add ethylene glycol base coolant that meets GM
Specification 1899-M when coolant has to be added because
of coolant loss or to provide added protection against
freezing at temperatures lower than -34°F (-37°C).
• Alcohol or methanol base coolants or plain water
alone should not be used in a vehicle at any time.
The cooling system should be serviced each year (15,-
000 miles, 24 000 km, on light duty emission service) (12,-
000 miles, 19 200 km, on heavy duty emission and diesel
engine vehicle service) as follows:
1. Wash radiator cap and filler neck with clean water.
2. Check coolant level and test for freeze protection.
3. Test system and radiator cap for proper pressure
holding capacity, 15 psi (105 kPa). If replacement cap is
needed, use a cap designed for coolant recovery systems and
specified model.
4. Tighten hose clamps and inspect all hoses. Replace
hoses if swollen, "checked", or otherwise deteriorated.
5. Clean frontal area of radiator core and air
conditioning condenser.
Flush and Refill
Every two years, 30,000 miles (48 000 km) on light
duty emissions or 24,000 miles (38 400 km) on heavy duty
emissions and diesel engine vehicles, whichever occurs first,
the cooling system should be flushed and refilled as follows:
1. Remove radiator cap when engine is cool:
• Turn cap slowly to the left until it reaches a "stop"
(Do not press down while turning the cap).
• Wait until pressure is relieved (indicated by a hissing
sound); then press down on cap and continue to rotate to
the left.
CAUTIO N: To help avoid the danger of
being burned, do not remove the radiator
cap w hile the engine and radiator are still
hot. Scalding fluid and steam can be
blown out under pressure if the cap is
taken o ff too soon.
2. With radiator cap removed, run the engine until
upper radiator hose is hot (this shows that the thermostat
is open and the coolant is flowing through the system).
3. Stop engine and open radiator drain valve to drain
coolant. (Drainage may be speeded by removing drain plugs
in the block.)
4. Close drain valve (install block drain plugs, if
removed). Add water until system is filled.
5. Repeat steps 3, and 4 several times until the drained
liquid is nearly colorless.
6. Drain system and then close radiator drain valve
tightly. (Install block drain plugs, if removed.)
7. Remove recovery tank cap, leaving hoses in place.
Remove coolant recovery tank and empty fluid. Scrub and
clean inside of tank with soap and water. Flush well with
clean water and drain. Reinstall tank.
M A IN T EN A N C E AND LUBRICATIO N
8. Add enough ethylene glycol solution, meeting GM
Specification 1899-M, and water to provide the required
cooling function as well as freezing and corrosion
protection. Use a 50 percent solution, -34°F (-36°C), but no
more than a 70 percent solution. Fill radiator to the base
of the radiator filler neck and raise level of coolant in the
recovery tank to the "Full Hot" mark. Reinstall recovery
tank cap.
9. Run engine, with radiator cap removed, until
radiator upper hose is hot.
10. With engine idling, add coolant to radiator until
level reaches bottom of filler neck. Install cap, making sure
arrows line up with overflow tube.
Radiator Pressure Cap
The radiator cap, a 15 psi (105 kPa) pressure type, must
be installed tightly, otherwise coolant may be lost and
damage to engine may result from overheating. Radiator
pressure cap should be checked periodically for proper
operation.
Therm ostat
The engine coolant temperature is controlled by a
thermostat. It stops coolant flow through the radiator until
a pre-set temperature is reached. This thermostat is installed
on the engine block. The same thermostat is used in both
winter and summer. Refer to Section 6B-Engine Cooling for
additional information.
A -1 1 M anual Steering Gear
The steering gear is factory-filled with steering gear
lubricant. Seasonal change of this lubricant should not be
performed and the housing should not be drained-no
lubrication is required for the life of the steering gear.
Inspect for seal leakage (actual solid grease-not just oily
film). If a seal is replaced or the gear is overhauled, the gear
housing should be refilled only with the proper Steering
Gear Lubricant as noted below.
NOTICE: Use only 1052182 (13 oz. (.38L) container)
Steering Gear Lubricant
Specification 4673M, or its equivalent.
Do not use EP chassis lube, meeting GM
Specification 6031M, to lubricate the gear. DO NOT
OVER-FILL the gear housing.
A -12 Clutch Cross-Shaft
Remove the plug, install a lubrication fitting and
lubricate with water resistant EP Chassis Lubricant which
meets GM Specification 6031M.
A -13 Autom atic Transmission Fluid
Refer to A-1 for checking automatic transmission.
Change the transmission fluid and service screen every 15,-
000 miles (24 000 km) on light duty emissions or 12,000
miles (19 200 km) on heavy duty emission and diesel engine
vehicles if the vehicle has been driven under one or more
of these hot conditions:
• In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C).
• In hill or mountain areas.
• Frequent trailer pulling.
• Uses such as taxi, police or delivery service. If
the vehicle was not used mainly under any of these
conditions, change the fluid and service screen each
100,000
OB-13
which meets GM
LIG H T D U TY T R U CK SER V IC E M AN UAL