Engine Cooling Fan Ford Tempo 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. In addition, many cars use a fan clutch (incorporating a thermostatic control) or flexible fan blade. These reduce noise and power requirements at higher engine speeds.

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 anti-freeze.

DRAINING

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

CLEANING

A good cleaning compound removes most rust and scale. Follow manufacturer's instructions in the use of the 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 of radiator.

FLUSHING

1. Back flushing is a very effective means of removing rustand 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. Use a leadaway hose, connected to radiator inlet, to prevent flooding the engine. Use air in short bursts only as a clogged radiator could be easily damaged. 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 the engine block. After system is full, continue running engine until thermostat is open, then recheck fill level. Do not overfill system. Refer to appropriate article for correct cooling system capacity.

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 (AMC recommends 100% anti-freeze). (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. (Scheme 1): Testing Thermostat in Anti-Freeze/Water Solution 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.

PRESSURE TESTING RADIATOR CAP

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

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

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

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 1 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. (Scheme 8): Pressure Testing Cooling System NOTE: Pump up to specified pressure.

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. Follow tester manufacturer's instructions for correct use of tester.

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. No adjustment or test is required except keeping vent hole or hose clean and checking 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, a vacuum is formed in the system. The vacuum draws coolant, stored in overflow bottle, back into radiator. In a properly maintained cooling system, the only coolant losses will be through evaporation.

Typical Coolant Recover System. Scheme 9

Note. Overflow bottle captures & releases coolant according to temperature.

THERMOSTATICALLY CONTROLLED ELECTRIC COOLING FANS

ELECTRIC COOLING FAN APPLICATIONS

The electro-drive cooling fan system consists of a fan and electric motor attached to a fan shroud located behind the radiator. The system utilizes a coolant temperature switch mounted in the thermostat housing. Vehicles equipped with air conditioning have a cooling fan controller and cooling fan relay for the cooling fan system. On vehicles with a standard heater, the engine cooling fan is powered through the cooling fan relay.

The electro-drive cooling fan is wired to operate only when the ignition switch is in the "RUN" position on Tempo and Topaz vehicles. The cooling fan will operate whenever the cooling fan temperature switch is closed on Escort.

If the vehicle is equipped with A/C, the cooling fan will then be controlled by the cooling fan controller and a fan relay. The cooling fan motor will be energized whenever the A/C cycling pressure switch closes with the select lever in "A/C" or "DEFROST" position. The A/C clutch coil will be energized once voltage is available at the fan motor. The A/C clutch will cycle with the A/C clutch cycling pressure switch.

The fan motor will stay energized as the clutch cycles if the cycling pressure switch open intervals are less than 2-3 minutes in duration. If the coolant temperature switch closes in the A/C mode at 210°F (55°C) on Escort, the fan motor will run continuously until the coolant temperature drops below 193°F (75°C). Fully depressing the throttle will also de-energize the A/C clutch coil.

Two different fan controllers are used, depending on the vehicle. Proper operation of the cooling system cannot be obtained unless the proper fan controller is used. Each controller is identified with a color code and part number.

The function control lever controls system vacuum and electrical operation. Vacuum motors operate doors to direct air flow. The electrical switches attached to the function control lever connect power to the blower motor, the clutch cycling pressure switch, and the A/C fan controller.

The cooling fan motor will be energized when the A/C select lever is moved to the "A/C" or "DEFROST" position. The fan will be energized first, then the A/C clutch will be powered if voltage is available at the cooling fan. The fan has limited cycling (2-3 minutes intervals) while the A/C clutch cycles with the A/C cycling pressure switch.

The cooling fan operates when the engine coolant temperature goes above 210°F (85°C) or when the A/C is operated. When there is low refrigerant suction pressure, the clutch cycling pressure switch signals the A/C fan controller to cut off power to the A/C clutch field coil, fan motor and throttle solenoid kicker.

The cooling fan controller on Escort is located under the instrument panel, forward of the evaporator mounting bracket. On Tempo and Topaz, the controller is mounted on the right cowl panel under the instrument panel. The controller can be serviced through the glove compartment opening.

Condition & Cause

Incorrect cooling or other air conditioning electrical system malfunctions may not be alleviated by replacing the A/C fan controller.

Diagnosis Procedure

Use the following fan controller and A/C electrical system diagnostic chart and the appropriate Chassis Wiring Diagram in the WIRING DIAGRAM Section to resolve an inoperative A/C cooling fan concern before replacing the A/C fan controller.

Note. The replacement parts have internal circuit protection. When the new controllers are used to service these vehicles, terminals #2 and #4 are not used. These two terminals are used only the Tempo/Topaz.

Keep the following points in mind when checking the A/C ckts

Scheme 10

1. For A/C operation, voltage must be available at fan controller pin #3.
2. The A/C clutch coil current must not exceed 6 amps.
3. Use a jumper wire to supply the proper voltage or ground to check fault or proper operation of the cooling fan A/C system if voltage or ground is not available at the controller.
4. Check for voltage at the controller with: the connector plugged into the controller. the key in the "RUN" position, except where an exception is noted.
5. Check for the following items at the cooling fan, coolant switch splices and connector/terminals if there is intermittent A/C operation: breaks poor crimps loose terminals

COOLING FAN CONTROLLER

A cooling fan controller is used with all models equipped with A/C, to control engine cooling fan operation. The system components consist of a cooling fan and electric motor connected to the fan shroud, coolant temperature sensor mounted in the thermostat housing, cooling fan controller and relay. Whenever the coolant temperature is above 210°F (117°C) and the ignition switch in the "RUN" position (Tempo and Topaz only), the cooling fan controller signals the cooling fan motor to operate. The engine cooling fan will operate during A/C compressor operation and will cycle on and off with the compressor clutch.

The cooling fan controller is located below the instrument panel forward of the evaporator mounting bracket on Escort models. On Tempo and Topaz models the controller is located on the right side cowl panel under the instrument panel and can be serviced through the glove box opening. Each cooling fan controller has the part number stamped on the housing. It is important that the correct controller be installed for proper operation.

If the cooling fan controller is suspected of not operating properly, diagnosis can be performed by taking voltage and/or continuity readings at the controller connector with controller plugged in. These readings are taken under the following 3 conditions: ignition switch off, ignition switch in "RUN" position while engine and A/C are off and ignition switch in "RUN" position with engine running and A/C on. The readings should be obtained at the indicated connector pins. If indicated voltage and/or continuity readings are not present, refer to wiring diagrams and COOLING FAN SYSTEM DIAGNOSIS WITH A/C .

Escort (Without A/C)

1. Disconnect fan motor connector. Install a jumper wire between negative lead and body ground. Apply battery voltage to positive lead. If fan motor does not run, replace motor. If fan motor does run, reconnect fan motor lead and go to next step.
2. Disconnect electrical connector at cooling fan temperature switch. With ignition off, check for battery voltage at circuit No. 197. If voltage is present go to next step. If voltage is not present, check for an open or short in circuit No. 197 and/or circuit breaker. Repair as necessary and recheck.
3. Install a jumper wire between terminals of cooling fan temperature switch connector. With ignition off, cooling fan should run. If so, replace cooling fan temperature switch and recheck operation. If not, leave jumper wire intact and go to next step.
4. Disconnect fan motor connector. With ignition off, check circuit No. 228 for battery voltage. If battery voltage is present, go to next step. If not, check circuit No. 228 and No. 182 for an open. Repair or replace as necessary and recheck operation.
5. Check ground circuit No. 57 for continuity to ground. If continuity is present, replace cooling fan motor, connect cooling fan temperature switch connector and recheck. If no continuity is present, repair open in circuit No. 57. Connect cooling fan motor connector and temperature switch connector and recheck operation.

Tempo & Topaz (Without A/C)

1. Disconnect fan motor connector. Install a jumper wire between negative lead and body ground. Apply battery voltage to positive lead. If fan motor does not run, replace motor. If fan motor does run, reconnect fan motor lead and go to next step.
2. Disconnect electrical connector at cooling fan temperature switch. With ignition in "RUN" position, check for battery voltage at circuit No. 197. If voltage is present, go to next step. If voltage is not present, check for an open or short in circuit No. 197. Repair as necessary and recheck operation.
3. Install a jumper wire between terminals of cooling fan temperature switch connector. With ignition in "RUN" position, cooling fan should run. If so, replace cooling fan temperature switch and recheck operation. If not, leave jumper wire intact and go to next step.
4. Disconnect fan motor connector. With ignition in "RUN" position, check circuit No. 228 for battery voltage. If battery voltage is present, go to next step. If not, check circuit No. 228 for an open. Repair or replace as necessary and recheck operation.
5. Check ground circuit No. 57 for continuity to ground. If continuity is present, replace cooling fan motor, connect cooling fan temperature switch connector and recheck operation. If no continuity is present, repair open in circuit No. 57. Connect cooling fan motor connector and temperature switch connector and recheck operation.

COOLING FAN SYSTEM DIAGNOSIS WITH A/C

Note. Once cooling fan controller pin voltage/continuity tests are performed and the controller is determined to be not at fault, refer to this section for diagnosis information. These procedures can be used to pinpoint problems in the controller and remaining components of the cooling fan system.

1. Check fuse and fusible link. Replace as necessary. If okay, determine when the cooling fan does or does not operate. If it operates during A/C operation only, go to step 2). If it does not operate during A/C operation or during high engine coolant temperatures, go to step 8). If it operates during high coolant temperatures only, go to step 6).
2. Turn ignition to "RUN" position and disconnect coolant temperature switch. Install a jumper wire between connector and ground with A/C off. If fan motor runs, go to next step. If not, go to step 5).
3. Verify coolant switch ground by checking for continuity between switch body and thermostat housing. Also check ground circuit for continuity. If no switch continuity exists, tighten coolant switch until continuity is achieved.
4. Verify coolant temperature has exceeded 210°F (84.7°C) by idling vehicle for about 25 minutes. If cooling fan motor operates, cooling fan system is okay. If not, replace coolant temperature switch.
5. Unplug connector from cooling fan controller and check for continuity of circuit No. 197 from controller coolant temperature switch. If continuity exists, replace cooling fan controller. If not service open circuit.
6. Check fan controller system ground at terminal No. 5 of fan controller. If ground is okay, go to next step. If not, repair ground circuit.
7. Remove connector from cooling fan controller. Check for voltage at circuits No. 198 and No. 348 (Scheme 3)and (Scheme 8). If no voltage at one or both circuits, go to next step. If voltage is present, replace fan controller.
8. Remove connector from clutch cycling pressure switch and install a jumper wire between connector terminals. If fan motor engages, go to next step. If not, go to step 10).
9. Check A/C system for refrigerant charge pressure of 50 psi (3.5 kg/cm 2 ) with ambient temperature of about 50°F (10°C). If no refrigerant pressure is present, leak test, service and recharge system. If refrigerant pressure is above 50 psi, replace clutch cycling pressure switch.
10. Remove connector from A/C control assembly. Install jumper wire in between circuits No. 348 and No. 294. Check for voltage at circuit No. 198. (Scheme 3)and (Scheme 8). If voltage is present, replace A/C button switch and return to step 7). If no voltage is present, service open circuit.
11. Unplug connector at cooling fan motor. Apply battery voltage and ground to fan motor. If fan motor runs, go to next step. If not, replace cooling fan motor.
12. Remove jumper wire and reconnect connector to fan motor. Disconnect connector from cooling fan controller and turn ignition switch to run. Check for voltage at circuits No. 37, 687, 175, 198 and 348. Check for good ground at circuit No. 57. If voltage and grounds are okay, go to next step. If not, service circuits without voltage.
13. Install a jumper wire between circuit No. 37 and No. 228A at the cooling fan controller. If fan motor runs, replace fan controller. If not, go to next step.
14. On Escort models, check continuity between circuit No. 37 of the fan controller. Check for continuity between terminal No. 3 and of fan motor relay and circuit No. 228A. Check circuit No. 197 between coolant switch and fan motor relay. NOTE: Steps 15), 16) and 17) apply to Tempo and Topaz only.
15. Install a jumper wire between circuit No. 37 and No. 228 at the cooling fan controller. If fan motor runs, replace fan relay. If not, go to next step.
16. Unplug 5-way connector of the engine compartment mounted fan relay. Jumper circuit No. 37 to circuit No. 228A. If fan motor runs, go to next step. If not, service fan motor ground.
17. Install a jumper wire between circuit No. 57 and terminal No. 1 of the fan motor relay. Also install a jumper wire between circuit No. 37 and circuit No. 228. If fan motor runs, service faulty circuits. If not, replace fan relay.

Escort Without A/C Electric Cooling Fan. Scheme 11

Escort With A/C Electric Cooling Fan. Scheme 12

Tempo & Topaz Without A/C Electric Cooling Fan. Scheme 13

Tempo & Topaz With A/C Electric Cooling Fan. Scheme 14

This unit is a fixed blade assembly designed to flex the blades as the engine RPM increases. As RPM increases blade pitch decreases, thereby saving power and decreasing noise level. No adjustment or test is required beyond keeping the fan belt adjusted to the proper tension.

Flex Blade Fan Assembly. Scheme 15

Most air conditioned models use a thermostatically controlled fluid fan and torque control clutch. The thermal control drive is a silicone-filled coupling connecting the fan to the fan pulley, and is operated by a control valve. Control valve is operated by a temperature sensitive bimetal coil or strip and controls the flow of silicone through the clutch.

During periods of operation when radiator discharge air temperature is low, the fan clutch limits the fan speed. High radiator discharge air temperature causes bimetal to allow a greater flow of silicone to enter the clutch. This increases the drag between the driven member and driving member resulting in a higher fan speed and increased cooling.

TESTING

In cases of engine overheating or insufficient air conditioning proceed with the following tests

Scheme 16

1. Start with a cool engine to ensure complete fan clutch disengagement.
2. Cover radiator grille sufficiently to induce high engine temperature.
3. Start engine and operate at 2000 RPM. Turn on air conditioning if equipped.
4. A fan roar will be noticed when the fan clutch engages. (Scheme 16): Thermostatically Controlled Fan Assembly NOTE: Shown with stamped face and bi-metal coil spring. NOTE: It will take approximately 5 to 10 minutes for the temperature to become high enough to allow engagement of the fan clutch. While operating engine under these conditions, observe temperature light to prevent overheating. If hot light comes on, remove cover from radiator grille.
5. As soon as the clutch engages, remove the radiator grille cover and turn the A/C off to assist in engine cooling.
6. After several minutes the fan clutch should disengage. This can be determined by a reduction in fan speed and roar. If the fan fails to function as described, it should be replaced.

See also:
• COOLING FAN SYSTEM DIAGNOSIS WITH A/C