Engine Cooling Fan Dodge Daytona 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 house 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.

THERMOSTAT

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.
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. Support thermometer so it does not touch bottom of container.

Testing Thermostat in Anti-Freeze/Water Solution. Scheme 1

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.

Testing Radiator Pressure Cap. Scheme 2

Note. Wet cap gasket before testing.

COOLING SYSTEM

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.
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 3): 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 Recovery System. Scheme 4

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

THERMOSTATICALLY CONTROLLED ELECTRIC COOLING FANS

ELECTRIC COOLING FAN APPLICATIONS

All FWD models use electric motor driven cooling system fans. The fan modules include a motor support which may (depending on model) include a shroud. The module is fastened to the radiator by clips or bolts. There are a number of combinations of fan motor sizes and RPM, as well as fan sizes.

Note. There are no repairs to be made to the fan. If the fan is warped, cracked, or otherwise damaged, it must be replaced with only the recommended part for adequate strength, performance and safety.

Fan control is accomplished 2 ways. The fan always runs when the A/C compressor clutch is engaged. In addition to this control, the fan is turned on by the temperature of the coolant which is sensed by the coolant temperature sensor which sends the message to the on-board computer. The computer turns on the fan through the fan relay.

Switching through the on-board computer provides for fan control. The fan should not run during cranking until the engine starts, no matter what the coolant temperature is. Fan should always run when the A/C clutch is engaged.

On non-A/C vehicles or with A/C off, the fan should run at vehicle speeds above about 40 MPH only if coolant temperature reaches 230°F (110°C) and will turn off when the temperature drops to 220°F (104°C).

At speeds below 40 MPH the fan switches on at 210°F (99°C) and off at 200°F (93°C). The fan will run only below 60°F (16°C) ambient, from 100°F (38°C) to 195°F (97°C) coolant temperature, only at idle, and zero car speed and then only for 3 minutes.

Note. At idle with A/C off, temperature gauge will rise slowly to about 5/8 gauge travel, the fan will come on and the gauge will quickly drop to about 1/2 gauge travel. This is normal.

Electric Fan Motor

To check the electric fan motor, disconnect fan motor wire connector. Observing correct polarity, connect a 12-volt battery source and ground to the fan motor connector. Positive side of connector is male and negative side is female. If the fan runs normally, the motor is functioning properly. If not, replace motor.

Note. If the motor is noticeably overheated, system voltage may be too high. Check charging system.

Fan Relay & Single Module Engine Controller (SMEC)

1. Bring engine to normal running temperature. Check fan motor wiring harness connector for proper engagement. Check the computer for fault codes. If fault codes 88, 12, 35 and 55 are detected, proceed to step 3).
2. Code 88 indicates start of diagnostic mode. This code must appear first in the diagnostic mode or fault codes will be inaccurate. Code 55 indicates end of diagnostic mode. Code 12 will be present if the SMEC has been cleared within the last 50-100 engine starts. Code 35 is a fault in the radiator fan relay circuit.
3. With ignition switch in run position, test for battery voltage at single pin connector at fan relay. If voltage reading is okay, proceed to step 4). Voltage at 0-1 volt, proceed to step 5).
4. With ignition off, disconnect 60-pin connector from SMEC and return ignition to run position. Test for battery voltage at cavity No. 57 of connector. If voltage is okay and female terminal is not damaged, replace the SMEC. With a zero voltage reading, repair open or short in the circuit.
5. With ignition off, disconnect 60-pin connector from SMEC and return ignition to run position. Test for battery voltage at single pin connector at fan relay. If voltage reading is okay, replace the SMEC. With a voltage reading of 0-1 volt, proceed to step 6).
6. With ignition in run position, test for battery voltage at Blue wire in 3-way connector of fan relay. If voltage is okay, replace fan relay. If voltage is reading zero, repair open or short in circuit. Turn ignition off, connect 60-pin connector to SMEC and test system.

SMEC 60-Pin Connector. Scheme 5

This fixed blade assembly is designed to allow the blades to flex as 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 6

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

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.

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

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.
4. A fan roar will be noticed when the fan clutch engages.
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.

Note. Shown with stamped face and bi-metal coil spring.

Thermostatically Controlled Fan Assembly. Scheme 7