Cooling System Specifications Oldsmobile Cutlass Ciera I

DESCRIPTION

The basic liquid cooling system consists of a radiator, water pump, thermostat, cooling fan, pressure cap, heater (if equipped), various connecting hoses and cooling passages in the block and cylinder head. Many cars use a fan clutch (incorporating a thermostatic control) or flexible fan blade. These reduce noise and power requirements at higher engine speeds. In addition, some cars use a thermostatically controlled electronic fan which is actuated by thermal relay switches. Some models may use a thermostatic vacuum switch to advance ignition timing in the event of overheating. Most models use a coolant recovery system to prevent loss of coolant.

Draining

Remove radiator cap and open heater control valve to maximum heat position. Open drain cocks or remove plugs in bottom of radiator and engine block. In-line engines usually have one plug or drain cock, while "V" type engines will have 2; one in each bank of cylinders.

Cleaning

A good cleaning compound will remove most rust and scale. Follow manufacturer's instructions in the use of cleaner. If considerable rust and scale has to be removed, flushing should be used. Clean radiator air passages by blowing with compressed air from back to front.

Flushing

1. Back flushing is a very effective means of removing rust and scale from a cooling system. For best results the radiator, engine and heater core should be flushed separately.
2. To flush radiator, connect flushing gun to water outlet of radiator and disconnect water inlet hose. To prevent flooding engine, use a leadaway hose connected to radiator inlet. Use air in short bursts only; this will prevent damage to radiator. Continue flushing until water runs clear.
3. To flush engine, first remove thermostat and replace housing. Connect flushing gun to water outlet of engine. Disconnect heater hoses from engine. Flush using short air bursts until water runs clean. Flush heater core as described for radiator. Make sure heater valve is set to maximum heat position before flushing heater.

Refilling

Engine should be running while refilling cooling system to prevent air from being trapped in engine block. After system is full, continue running engine until thermostat is open, then recheck fill level. Do not overfill system.

ANTI-FREEZE CONCENTRATION

Note. On models using aluminum engines or cooling system components, refer to Owners Manual for anti-freeze requirements and recommendations. Aluminum components require a different formulation of anti-freeze to prevent corrosion.

On all cooling systems, test anti-freeze concentration using anti-freeze tester. Tester should have a temperature-compensating feature, as failing to take temperature into consideration could cause an error as large as 30°F (-1°C). Follow tester manufacturer's instructions for correct use of tester.

Scheme 1

1. Visually inspect thermostat for corrosion and proper sealing of valve and seat. If satisfactory, suspend thermostat and a thermometer in a container with a 50/50 mixture of anti-freeze and water. (Scheme 1)
2. Do not allow either thermostat or thermometer to touch bottom of container as this concentration of heat could cause an incorrect reading. Heat water until thermostat just begins to open. NOTE: Support thermometer so it does not touch bottom of container.
3. Read temperature on thermometer. This is the initial opening temperature and should be within specifications. Continue heating water until thermostat is fully open and note temperature. This is the fully opened temperature. If either reading is outside of specifications, replace thermostat, as it is not adjustable. NOTE: General Motors Corp. recommends hanging thermostat in 33% glycol solution at 25°F (4°C) above temperature stamped on thermostat. Valve should open. Remove thermostat from solution and place in similar solution at 10°F (-12°C) below stamped temperature. Valve should close.

PRESSURE TESTING

A cooling system pressure tester is used to test both radiator cap and complete cooling system. Test as follows, following tool manufacturer's instructions.

Radiator Cap Pressure Testing

Visually inspect radiator cap, then dip cap in water and connect to tester. Pump tester to bring pressure to upper limit of cap specifications. If cap fails to hold pressure within specifications, replace cap.

Scheme 2

Wet cap gasket before testing.

Scheme 3

1. With engine off, wipe radiator filler neck seat clean. Fill radiator to correct level. Attach tester to radiator and pump until pressure is at upper limit of radiator rating.
2. If pressure drops, inspect for external leaks. If no leaks are apparent, detach tester and run engine until normal operating temperature is obtained. Reattach tester and observe. If pressure builds up immediately, a possible leak exists from a faulty head gasket or crack in head or block. CAUTION: Pressure may build up quickly. Release any excess pressure or cooling system damage may result.
3. If there is no immediate pressure build up, pump tester to within system pressure range (on radiator cap). Vibration of gauge pointer indicates compression or combustion leak into cooling system. Isolate leak by shorting each spark plug wire to cylinder block. Gauge pointer should stop or decrease vibration when leaking cylinder is shorted. CAUTION: Do not disconnect spark plug wires while engine is operating, or operate engine with spark plug shorted for more than one minute, as catalytic converter may be damaged.
4. Remove engine and transmission (automatic only) oil dipsticks and check if water drops appear in oil. If so, a serious internal leak is indicated. If all checks are negative and system holds pressure for 2 minutes, there are no serious leaks in system.

A coolant recovery system differs from other cooling systems in that an overflow bottle is connected to the radiator overflow hose. The overflow bottle is transparent or translucent to permit checking of coolant level without removing radiator cap. The only adjustment or test required is to keep vent hole or hose clean and to check pressure relief of radiator cap.

OPERATION

As coolant temperature rises and pressure in system exceeds pressure relief valve of radiator cap, excess coolant flows into overflow bottle. As engine cools and coolant contracts, vacuum is formed in the system. Vacuum draws coolant, stored in overflow bottle, back into radiator. In a properly maintained cooling system, the only coolant loss will be through evaporation.

Scheme 4

Thermostat

Most thermostats are thermal wax pellet type. As coolant temperatures rise the wax begins to expand. This expansion over comes spring tension allowing the thermostat to open. Some thermostats also incorporate an additional bleed hole to allow a small amount of circulation and helps eliminate air locks.

Pressure Cap

Modern cooling systems use a closed system type cap. This system allows for coolant expansion during engine operation. As coolant expands and builds pressure, some coolant is permitted to bleed past the cap into the over flow tank. When the engine cools and coolant contracts, the cap allows the coolant in the over flow tank to siphon back into the system.

The pressure cap also increases pressure in the cooling system. The increased pressure raises the boiling point, one pound of pressure raises the boiling point approximately 10° F (12.2° C).

Coolant Mixture

Engine coolant must be mixed with water to a specific percent. A 100% coolant mixture could cause system over heating or premature system failure. Coolants are designed to function best when mixed with water. The percentage of coolant to water can vary depending on climate condition, but a 50/50 mixture is a standard percentage.

Engine coolant should also include an aluminum protection additive. This will help protect against metal deterioration.

Maintenance

Periodic maintenance is necessary for extended cooling system and engine life. Because engine and cooling systems are made of different metals, electrolysis begins to destroy the metals. Changing the coolant at scheduled maintenance periods reduces electrolysis and removes sediment. See COOLANT REPLACEMENT SCHEDULE table.

Note. Approximate capacity figures are shown. Capacities may vary 15% due to system variations.

COOLING SYSTEM CAPACITIES

COOLANT REPLACEMENT SCHEDULE

See also:
• COOLANT REPLACEMENT SCHEDULE