Cooling Fan - Right
| Connector Part Information OEM: 13517352 Service: 88988506 Description: 2-Way F GT 280 Sealed (BK) |
|---|
| Terminal Part Information Terminal/Tray: 15304720/19 Core/Insulation Crimp: 4/5 Release Tool/Test Probe: 15315247/J-35616-4A (PU) |
Cooling Fan - Right Connector Parts Information
| Pin | Wire Color | Circuit No. | Function |
|---|---|---|---|
| A | L-BU | 409 | Cooling Fan Motor Supply Voltage |
| B | BK | 1250 | Ground |
Cooling Fan - Right Connector Terminal Identification
Electrical Information Reference
- «Circuit Testing»(ref-275031-S01352341682007122600000)
- «Connector Repairs»(ref-275031-S10085307342007122600000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-275031-S24367471382007122600000)
- «Wiring Repairs»(ref-275031-S25744209472007122600000)
Circuit/System Verification
- Ignition ON, command the cooling fan relay 1 ON and OFF several times using the scan tool output control function. You should hear both fans turn ON and OFF. Both should run on low speed when turned ON.
- Command the cooling fan relays 2 and 3 ON and OFF several times using the scan tool output control function. When turned ON, the right fan should run on high and the left fan should remain OFF.
- Command the cooling fan relays 1, 2 and 3 ON and OFF several times using the scan tool output control function. When turned ON, both fans should run on high speed.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Relay Replacement (Attached to Wire Harness)»(ref-275032-S07652464112007122600000) or «Relay Replacement (Within an Electrical Center)»(ref-275032-S41334127562007122600000)
- «Control Module References»(ref-275033-S19313861122007122600000) for ECM replacement, setup and programming
- If DTC P0480 or P0481 are set, diagnose those DTCs first.
- Observe the engine coolant level. The engine coolant level should be within the operating range. Refer to Capacities - Approximate Fluid and Engine Coolant in the Owner's Manual.
- Ensure that the vehicle has the correct engine coolant with correct concentration and is not old, contaminated or contains additives. Refer to Recommended Fluids and Lubricants in the Owner's Manual.
- Inspect the cooling system for the following: Leaks Kinked or pinched hoses, especially at the radiator Loose, missing or damaged radiator air seals or deflectors Air flow obstructions or bent fins at the radiator or the A/C condenser-Refer to «Symptoms - Engine Cooling»(ref-275043-S17655960832007122600000) .
- Command the cooling fans ON and OFF, low and high speed. The engine cooling fans should turn ON and OFF with each command. If the cooling fans do not function as indicated, refer to «Cooling Fan Inoperative»(ref-275043-S32172512062007122600000) .
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Identifying Intermittent Conditions
Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movement of a component. Refer to the following for a list to help determine an intermittent condition
- Moisture and water intrusion in connectors, terminals and components
- Connector mating
- Terminal contact
- High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
- Harness that is located too tight or chaffed circuits
- High or low ambient temperature
- High or low engine coolant temperatures
- High underhood temperatures
- Heat build up in component or circuit due to circuit resistance, poor terminal contact or high electrical load
- High or low system voltage
- High vehicle load conditions
- Rough road surface
- Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
- Incorrect installation of non-factory, aftermarket and after factory add on accessories
If an intermittent is determined, refer to Testing for Intermittent Conditions and Poor Connections for specific strategies in diagnosing intermittent conditions.
- «Circuit Testing»(ref-275031-S01352341682007122600000)
- «Connector Repairs»(ref-275031-S10085307342007122600000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-275031-S24367471382007122600000)
- «Wiring Repairs»(ref-275031-S25744209472007122600000)
- «Engine Overheating»(ref-275043-S24750515192007122600000)
- «Instrument Cluster Replacement»(ref-275011-S27329439392007122600000)
Repair Verification
Verify that the ECT indicator is OFF while the engine is operating.
Reference Information
Schematic Reference
Engine Cooling Schematics
Connector End View Reference
Cooling System Connector End Views
Description and Operation
Cooling Fan Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-275031-S01352341682007122600000)
- «Connector Repairs»(ref-275031-S10085307342007122600000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-275031-S24367471382007122600000)
- «Wiring Repairs»(ref-275031-S25744209472007122600000)
Scan Tool Reference
Scan Tool Data List
- If DTCs P0480 or P0481 are set, perform those diagnostics first.
- Ignition ON, verify with a scan tool that the control module is not commanding fan activation.
- Observe that the fans are not activated.
- Ignition ON, verify with a scan tool that the control module is not commanding fan activation.
- Ignition ON, observe that the fans are not activated.
- «Circuit Testing»(ref-275031-S01352341682007122600000)
- «Connector Repairs»(ref-275031-S10085307342007122600000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-275031-S24367471382007122600000)
- «Wiring Repairs»(ref-275031-S25744209472007122600000)
- Verify that DTCs P0480 or P0481 are not set. If either of the DTCs are set, repair the DTC first.
- Ignition ON, command high and low speed fans ON and OFF with a scan tool. Observe to verify that the fans turn ON and OFF when changing between the commanded states.
- «Engine Coolant Fan Motor Replacement»(ref-275043-S38964901462007122600000)
- «Relay Replacement (Attached to Wire Harness)»(ref-275032-S07652464112007122600000) or «Relay Replacement (Within an Electrical Center)»(ref-275032-S41334127562007122600000)
Ignition ON, command the fan relay ON and OFF with a scan tool. Observe to verify that the appropriate fan turns ON and OFF with each command.
Engine Overheating
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| DEFINITION: The engine temperature lamp comes on and stays on, the temperature gauge shows hot or coolant overflows from the coolant recovery reservoir onto the ground while the engine is running. | ||||
| 1 | Check for a loss of coolant. Has there been a loss of coolant? | Go to Step 2 | Go to Step 3 | |
| 2 | Refer to Loss of Coolant . Does the engine still overheat? | Go to Step 3 | System OK | |
| 3 | Check for a loss of system pressure. Use the J 24460-01 Cooling System Pressure Tester. See Special Tools . Has there been a loss of system pressure? | Go to Step 4 | Go to Step 5 | |
| 4 | Correct the system pressure. Does the engine still overheat? | Go to Step 5 | System OK | |
| 5 | Check for low coolant protection. Make sure that the solution is at the specified temperature. Is there low coolant protection? | 37°C (-34°F) | Go to Step 6 | Go to Step 7 |
| 6 | Correct as necessary. Does the engine still overheat? | Go to Step 7 | System OK | |
| 7 | Check the accessory drive belt tension. Check the tensioner. Refer to Drive Belt Tensioner Diagnosis . Is the tensioner working properly and the tension correct? | Go to Step 9 | Go to Step 8 | |
| 8 | Replace the tensioner. Refer to Drive Belt Tensioner Diagnosis . Does the engine still overheat? | Go to Step 9 | System OK | |
| 9 | Check to see if the timing is retarded by a malfunctioning powertrain control module (PCM). Is the timing retarded by a malfunctioning PCM? | Go to Step 10 | Go to Step 11 | |
| 10 | Correct as necessary. Does the engine still overheat? | Go to Step 11 | System OK | |
| 11 | Check to see if any of the radiator fins are obstructed. Are any of radiator fins obstructed? | Go to Step 12 | Go to Step 13 | |
| 12 | Remove or relocate any add-on parts that block air to the radiator. Remove any debris from the radiator fins. Does the engine still overheat? | Go to Step 13 | System OK | |
| 13 | Check to see if any of the cooling system passages are blocked by rust or scale. Are any of the cooling system passages blocked by rust or scale? | Go to Step 14 | Go to Step 15 | |
| 14 | Drain the cooling system. Refer to Draining and Filling Cooling System (Static Fill) or Draining and Filling Cooling System (GE 47716 Fill) . Flush the cooling system. Refer to Coolant System Flushing . Repair as necessary. Does the engine still overheat? | Go to Step 15 | System OK | |
| 15 | Check for a pinched or kinked coolant recovery reservoir hose. Is the surge tank hose pinched or kinked? | Go to Step 16 | Go to Step 17 | |
| 16 | Replace or reroute the hose as necessary. Refer to Surge Tank Hose/Pipe Replacement - Inlet . Does the engine still overheat? | Go to Step 17 | System OK | |
| 17 | Check for an inoperative cooling fan. Refer to Cooling Fan Inoperative . Are there any inoperative cooling fans? | Go to Step 18 | Go to Step 19 | |
| 18 | Repair or replace the electric cooling fans as necessary. Refer to Engine coolant Fan Motor Replacement . Does the engine still overheat? | Go to Step 19 | System OK | |
| 19 | Check for a loose, damaged, and/or missing deflector. Are there any loose, damaged or missing deflectors? | Go to Step 20 | Go to Step 21 | |
| 20 | Replace the deflectors. Does the engine still overheat? | Go to Step 21 | System OK | |
| 21 | Check to see if the thermostat is stuck in the closed position. Is the thermostat stuck in the closed position? | Go to Step 22 | Go to Step 23 | |
| 22 | Replace the thermostat. Refer to Thermostat Replacement . Does the engine still overheat? | Go to Step 23 | System OK | |
| 23 | Check for a faulty coolant pump. Is the coolant pump faulty? | Go to Step 24 | Go to Step 25 | |
| 24 | Replace the water pump. Refer to Water Pump Replacement . Does the engine still overheat? | Go to Step 25 | System OK | |
| 25 | Check for an incorrect radiator. Is the radiator correct? | Go to Step 26 | ||
| 26 | Install the correct radiator. Refer to Radiator Replacement . Does the engine still overheat? | System OK | ||
Engine Overheating
Loss of Coolant
| Step | Action | Yes | No |
|---|---|---|---|
| DEFINITION: The cooling system is losing coolant either internally or externally. | |||
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - Engine Cooling |
| 2 | Repair any present DTCs. Refer to Diagnostic Trouble Code (DTC) List - Vehicle . Is the action complete? | Go to Step 3 | |
| 3 | Inspect the coolant level. Is the coolant at the proper level? | Go to Step 6 | Go to Step 4 |
| 4 | Fill the cooling system to the proper level. Refer to Draining and Filling Cooling System (Static Fill) or Draining and Filling Cooling System (GE 47716 Fill) . Is the action complete? | Go to Step 5 | |
| 5 | If the engine is suspected to have a coolant leak into a cylinder, the coolant can hydraulically lock the engine. Does the engine crankshaft rotate? | Go to Step 6 | Go to Step 26 |
| 6 | Engine overheating can cause a loss of coolant. Is the engine overheating? | Go to Step 27 | Go to Step 7 |
| 7 | Extended operation with a low coolant level can cause engine internal component failure. Is the engine knocking? | Go to Step 29 | Go to Step 8 |
| 8 | Idle the engine at normal operating temperature. Inspect for heavy white smoke coming out of the exhaust pipe. Is a heavy white smoke present from the exhaust pipe? | Go to Step 9 | Go to Step 10 |
| 9 | Coolant in the exhaust system creates a distinctive, burning coolant odor in the exhaust. Condensation in the exhaust system can cause an odorless white smoke during engine warm up. Does the white smoke have a burning coolant type odor? | Go to Step 28 | Go to Step 10 |
| 10 | With the engine idling, inspect the coolant recovery system. Does the coolant recovery system discharge coolant while the engine is idling? | Go to Step 15 | Go to Step 11 |
| 11 | Visually inspect the hoses, pipes and hose clamps at the following locations: Coolant surge tank Heater core Radiator Are any of the hoses, clamps or pipes leaking? | Go to Step 20 | Go to Step 12 |
| 12 | Visually inspect the following components: The coolant pressure cap The core plugs The cylinder head gaskets The engine block The intake manifold The radiator The thermostat housing The water pump Are any of the listed components leaking? | Go to Step 20 | Go to Step 13 |
| 13 | Pressure test the cooling system. Refer to Cooling System Leak Testing . With the cooling system pressurized, visually inspect the components listed in steps 11 and 12. Are any leaks present? | Go to Step 20 | Go to Step 14 |
| 14 | Pressure test the coolant pressure cap. Refer to Pressure Cap Testing . Does the coolant pressure cap hold pressure? | Go to Step 16 | Go to Step 21 |
| 15 | Pressure test the coolant pressure cap. Refer to Pressure Cap Testing . Does the coolant pressure cap hold pressure? | Go to Step 30 | Go to Step 21 |
| 16 | Inspect for the following conditions: A coolant smell inside of the vehicle Coolant in the HVAC module drain tube Coolant on the vehicle floor covering near the HVAC module Is coolant present? | Go to Step 22 | Go to Step 17 |
| 17 | Inspect the underside of the engine oil fill cap for a gray/white milky substance. Is there a milky substance on under the oil fill cap? | Go to Step 18 | Go to Step 19 |
| 18 | Inspect the engine oil fluid level indicator for a gray/white milky substance. Is there a milky substance on the engine oil fluid level indicator? | Go to Step 28 | Go to Step 19 |
| 19 | Inspect the automatic transmission oil fluid level indicator, if equipped, for a gray/white milky substance. Is there a milky substance on the automatic transmission fluid level indicator? | Go to Step 23 | Go to Step 31 |
| 20 | Repair or replace the leaking component. Refer to the appropriate repair. Is the repair complete? | Go to Step 31 | |
| 21 | Replace the coolant pressure cap. Is the repair complete? | Go to Step 31 | |
| 22 | Replace the heater core. Refer to Heater Core Replacement . Is the repair complete? | Go to Step 31 | |
| 23 | Remove the transmission oil cooler lines from the radiator. Pressure test the cooling system. Refer to Cooling System Leak Testing . Inspect the transmission oil cooler for coolant. Is coolant present? | Go to Step 24 | Go to Step 25 |
| 24 | Replace the radiator. Refer to Radiator Replacement . Service the automatic transmission. Refer to Engine Coolant/Water in Transmission . Is the repair complete? | Go to Step 31 | |
| 25 | Install the cooler lines to the radiator. Is the action complete? | Go to Step 31 | |
| 26 | Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate . Is the repair complete? | Go to Step 31 | |
| 27 | Repair the engine overheating condition. Is the repair complete? | Go to Step 31 | |
| 28 | Repair the engine internal coolant leak. Refer to Coolant in Combustion Chamber . Is the repair complete? | Go to Step 31 | |
| 29 | Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed . Is the repair complete? | Go to Step 31 | |
| 30 | Repair the combustion pressure in the cooling system problem. Refer to Cylinder Leakage Test . Is the repair complete? | Go to Step 31 | |
| 31 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
Loss of Coolant
Tools Required
J 24731 Tempilstick. See Special Tools .
The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a pencil like device. It has a wax material containing certain chemicals which melt at a given temperature. Temperature sticks can be used to determine a thermostat's operating range, by rubbing 87°C (188°F) and 97°C (206°F) sticks on the thermostat housing.
- «Circuit Testing»(ref-275031-S01352341682007122600000)
- «Connector Repairs»(ref-275031-S10085307342007122600000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-275031-S24367471382007122600000)
- «Wiring Repairs»(ref-275031-S25744209472007122600000)
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Coolant Heater Replacement»(ref-275043-S32773268902007122600000)
- «Coolant Heater Cord Replacement»(ref-275043-S11099609092007122600000)
Engine Fails To Reach Normal Operating Temperature
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Ensure that the cooling system is full. Allow the engine/radiator cap to cool. Start the engine. Turn the air conditioning system off. Inspect the engine cooling fans. Is either engine cooling fan on? | Go to Step 2 | Go to Step 3 |
| 2 | Diagnose and repair the cooling fan system. Refer to Cooling Fan Always On . Verify the customer complaint. Does the engine still fail to reach normal operating temperature? | Go to Step 3 | System OK |
| 3 | Install the Scan Tool to the DLC. Compare the Scan Tool coolant temperature reading to the I/P cluster coolant temperature. Is the I/P cluster coolant temperature close to the Scan Tool coolant temperature? | Go to Step 5 | Go to Step 4 |
| 4 | Diagnose and repair the coolant temperature gage system. Refer to Engine Coolant Temperature Gage Inaccurate or Inoperative . Verify the customer complaint. Does the engine still fail to reach normal operating temperature? | Go to Step 5 | System OK |
| 5 | CAUTION: As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously - possibly with explosive force - spewing the solution over the engine, fenders and the person removing the cap. Inspect the thermostat for proper operation.Is the thermostat operating properly? | Go to Step 1 | Go to Step 6 |
| 6 | Replace the thermostat. Refer to Thermostat Replacement . Verify the customer complaint. Does the engine still fail to reach normal operating temperature? | Go to Step 1 | System OK |
| CAUTION |
|---|
| As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously - possibly with explosive force - spewing the solution over the engine, fenders and the person removing the cap. |
Engine Fails To Reach Normal Operating Temperature
- J 24460-01 Cooling System Pressure Tester. See «Special Tools»(ref-275043-S37942007642007122600000) .
- J 42401 Radiator Cap/Surge Tank Test Adapter. See «Special Tools»(ref-275043-S37942007642007122600000) .
- J 24460-01 Cooling System Pressure Tester. See «Special Tools»(ref-275043-S37942007642007122600000) .
- J 42401 Radiator Cap/Surge Tank Test Adapter. See «Special Tools»(ref-275043-S37942007642007122600000) .
Filling Procedure
| IMPORTANT | When the radiator is drained, a minimum of 5 liters (5.28 qts) of coolant is typically drained from the cooling system. During the fill procedure, a minimum of 5 liters (5.28 qts) of coolant should be added to the cooling system before the vehicle is returned to the customer. |
- Close the drain valve on the left radiator end tank.
- Install the engine block drain plug, if removed.
- Open the air bleed screw on the water pump tower.
- Slowly add a mixture of 50/50 DEX-COOL antifreeze and clean water to the surge tank. Refer to «Approximate Fluid Capacities»(ref-275070-S32741816652007122600000) for cooling system capacity. As the system begins to fill, watch for coolant at the water pump tower. As coolant begins to seep from the air bleed, close the air bleed screw. Once the bleed screw is closed, continue to add coolant until a minimum of 5 liters (5.28 qts) is added to the cooling system. Start the engine and run at idle to add the remaining coolant.
- Install the surge tank cap.
- Run the engine and cycle the vehicle from idle to 3,000 RPM in 30 second intervals until the engine cooling fans come ON.
- Return the engine to idle, idle for 30 seconds then turn the engine OFF.
- Allow the vehicle to cool.
- Add coolant to the surge tank until the level is approximately 25 mm (1 in) above the top of the Cold Fill Range at the surge tank seam.
- Install the surge tank cap.
- J 26568 Coolant and Battery Fluid Tester. See «Special Tools»(ref-275043-S37942007642007122600000) .
- GE-47716 Vac N Fill Coolant Refill Tool. See «Special Tools»(ref-275043-S37942007642007122600000) .
- J 42401 Radiator Pressure Adapter. See «Special Tools»(ref-275043-S37942007642007122600000) .
GE-47716 1617 Vac N Fill Coolant Refill Tool. See Special Tools .
GE-47827 Socket. See Special Tools .
Scheme 11
This vehicle is equipped with counter-rotating engine cooling fans. The right hand fan will require the use of GE-47827 for fan blade removal. See Special Tools . The left hand fan blade can be removed using a normal six point socket.
GE-47716 1617 Vac N Fill Coolant Refill Tool. See Special Tools .
J 21882 Oil Suction Pipe Installer. See Special Tools .
J 39914 Serpentine Belt Tensioner Unloader. See Special Tools .
GE-47716 Vac N Fill Coolant Refill Tool. See Special Tools .
GE-47716 Vac N Fill Coolant Refill Tool. See Special Tools .
Cooling Fan Control
The engine cooling fan system consists of 2 cooling fans and 3 relays. The relays are powered by the battery positive voltage circuit and controlled by a switched ground from the powertrain control module (PCM).
During low speed operation, the PCM supplies the ground path for the low speed cooling fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan low relay coil, closes the relay contacts and supplies battery positive voltage from the COOL FAN LO fuse through the cooling fan motor supply voltage circuit to the cooling fan. During high speed operation the PCM supplies the ground path for the cooling fan low relay through the low speed cooling fan relay control circuit. After a 3-second delay, the PCM supplies a ground path for the cooling fan high relay and the s/p cooling fan relay through the high speed fan relay control circuit.
The PCM commands the fan on under the following conditions
- Engine coolant temperature exceeds approximately 98°C (208°F) Low Fan Speed
- Engine coolant temperature exceeds approximately 102°C (216°F) High Fan Speed
- A/C refrigerant pressure exceeds 361 kPa (52 psi) Low Fan Speed
- A/C refrigerant pressure exceeds 2100 kPa (300 psi) High Fan Speed
- When the engine coolant temperature exceeds 112°C (234°F) at key off, the fan high speed will run for up to 300 seconds. If within that time frame 102°C (216°F) is reached then fan speed will change from high to low speed. If within that time frame 99°C (210°F) is reached then fan speed will change from low to off.
The PCM commands the fan off under the following conditions
- A/C is requested and engine speed exceeds 6,240 RPM
- Engine coolant temperature exceeds approximately 99°C (210°F) turns the cooling fans from low to off.
LOW COOLANT LEVEL
The IPC illuminates the low coolant warning indicator when any of the following occur
- The BCM detects a low coolant level condition for at least 30 seconds. The IPC receives a class 2 message from the BCM requesting illumination.
- The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.
Coolant Heater
The optional engine coolant heater (RPO K05) operates using 110-volt AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather -29°C (-20°F). The coolant heater helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. A weather shield on the cord is provided to protect the plug when not in use. The power cord has a thermal element in the cord end that does not allow current to the heater until the ambient temperature reaches 0°F or -18°C.
The cooling system's function is to maintain an efficient engine operating temperature during all engine speeds and operating conditions. The cooling system is designed to remove approximately one-third of the heat produced by the burning of the air-fuel mixture. When the engine is cold, the coolant does not flow to the radiator until the thermostat opens. This allows the engine to warm quickly.
Charge Air Cooling System (LSJ Only)
The charge air cooling systems function is to reduce the temperature of the air charge that is heated during the supercharging process which improves the efficiency of the supercharging system. The charge air cooling system is a water-to-air system that uses a dedicated electric coolant pump, a modified intake manifold and a separate charge air cooling radiator located between the condenser and the radiator to cool the air charge.
Cooling Cycle
Coolant flows from the radiator outlet and into the water pump inlet. Some coolant flows from the water pump, to the heater core, then back to the water pump. This provides the passenger compartment with heat and defrost capability as the coolant warms up.
Coolant also flows from the water pump outlet and into the engine block. In the engine block, the coolant circulates through the water jackets surrounding the cylinders where it absorbs heat.
The coolant then flows through the cylinder head gasket openings and into the cylinder heads. In the cylinder heads, the coolant flows through the water jackets surrounding the combustion chambers and valve seats, where it absorbs additional heat.
From the cylinder heads, the coolant flows to the thermostat. The flow of coolant will either be stopped at the thermostat until the engine reaches normal operating temperature or it will flow through the thermostat and into the radiator where it is cooled. At this point, the coolant flow cycle is completed.
Efficient operation of the cooling system requires proper functioning of all cooling system components. The cooling system consists of the following components
Coolant
The engine coolant is a solution made up of a 50-50 mixture of DEX-COOL and suitable drinking water. The coolant solution carries excess heat away from the engine to the radiator, where the heat is dissipated to the atmosphere.
Radiator
The radiator is a heat exchanger. It consists of a core and two tanks. The aluminum core is a tube and fin crossflow design that extends from the inlet tank to the outlet tank. Fins are placed around the outside of the tubes to improve heat transfer to the atmosphere.
The inlet and outlet tanks are a molded, high temperature, nylon reinforced plastic material. A high temperature rubber gasket seals the tank flange edge to the aluminum core. The tanks are clamped to the core with clinch tabs. The tabs are part of the aluminum header at each end of the core.
The radiator also has a drain cock located in the bottom of the right hand tank. The drain cock unit includes the drain cock and drain cock seal.
The radiator removes heat from the coolant passing through it. The fins on the core transfer heat from the coolant passing through the tubes. As air passes between the fins, it absorbs heat and cools the coolant.
Pressure Cap
The pressure cap seals the cooling system. It contains a blow off or pressure valve and a vacuum or atmospheric valve. The pressure valve is held against its seat by a spring, which protects the radiator from excessive cooling system pressure. The vacuum valve is held against its seat by a spring, which permits opening of the valve to relieve vacuum created in the cooling system as it cools off. The vacuum, if not relieved, might cause the radiator and/or coolant hoses to collapse.
The pressure cap allows cooling system pressure to build up as the temperature increases. As the pressure builds, the boiling point of the coolant increases. Engine coolant can be safely run at a temperature much higher than the boiling point of the coolant at atmospheric pressure. The hotter the coolant is, the faster the heat transfers from the radiator to the cooler, passing air.
The pressure in the cooling system can get too high. When the cooling system pressure exceeds the rating of the pressure cap, it raises the pressure valve, venting the excess pressure.
As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum causes the vacuum valve to open, allowing outside air into the surge tank. This equalizes the pressure in the cooling system with atmospheric pressure, preventing the radiator and coolant hoses from collapsing.
Surge Tank
The surge tank is a plastic tank that the pressure cap mounts onto. The tank is mounted at a point higher than all other coolant passages. The surge tank provides an air space in the cooling system. The air space allows the coolant to expand and contract. The surge tank also provides a coolant fill point and a central air bleed location. During vehicle use, the coolant heats and expands. The coolant that is displaced by this expansion flows into the surge tank. As the coolant circulates, air is allowed to exit. This is an advantage to the cooling system. Coolant without bubbles absorbs heat much better than coolant with bubbles.
Air Baffles and Seals
The cooling system uses deflectors, air baffles and air seals to increase cooling system capability. Deflectors are installed under the vehicle to redirect airflow beneath the vehicle and through the radiator to increase engine cooling. Air baffles are also used to direct airflow through the radiator and increase cooling capability. Air seals prevent air from bypassing the radiator and A/C condenser and prevent recirculation of hot air for better hot weather cooling and A/C condenser performance.
Water Pump
The water pump is a centrifugal vane impeller type pump. The pump consists of a housing with coolant inlet and outlet passages and an impeller. The impeller is mounted on the pump shaft and consists of a series of flat or curved blades or vanes on a flat plate. When the impeller rotates, the coolant between the vanes is thrown outward by centrifugal force.
The impeller shaft is supported by one or more sealed bearings. The sealed bearings never need to be lubricated. Grease cannot leak out, dirt and water cannot get in as long as the seal is not damaged or worn.
The purpose of the water pump is to circulate coolant throughout the cooling system. The water pump is driven by the crankshaft via the timing chain.
Thermostat
The thermostat is a coolant flow control component. It's purpose is to help regulate the operating temperature of the engine. It utilizes a temperature sensitive wax-pellet element. The element connects to a valve through a small piston. When the element is heated, it expands and exerts pressure against the small piston. This pressure forces the valve to open. As the element is cooled, it contracts. This contraction allows a spring to push the valve closed.
When the coolant temperature is below the rated thermostat opening temperature, the thermostat valve remains closed. This prevents circulation of the coolant to the radiator and allows the engine to warm up. After the coolant temperature reaches the rated thermostat opening temperature, the thermostat valve will open. The coolant is then allowed to circulate through the thermostat to the radiator where the engine heat is dissipated to the atmosphere. The thermostat also provides a restriction in the cooling system, after it has opened. This restriction creates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block.
Transmission Oil Cooler
The transmission oil cooler is a heat exchanger. It is located inside the left side end tank of the radiator. The transmission fluid temperature is regulated by the temperature of the engine coolant in the radiator.
The transmission oil pump, pumps the fluid through the transmission oil cooler line to the transmission oil cooler. The fluid then flows through the cooler where the engine coolant absorbs heat from the fluid. The fluid is then pumped through the transmission oil cooler return line, to the transmission.