Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Engine Overheating
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Inspect for a missing or damaged radiator side or upper baffle and/or radiator air deflector. Is the baffle and/or deflector missing or damaged? | Go to Step 8 | Go to Step 2 |
| 2 | Inspect for a loss of coolant. Is there a loss of coolant? | Go to Step 3 | Go to Step 4 |
| 3 | Fill the system to the specified level. Does the engine overheat? | Go to Step 4 | System OK |
| 4 | Inspect for low temperature protection. Is the coolant to the correct concentration? | Go to Step 5 | Go to Step 8 |
| 5 | Inspect for a loss of cooling system pressure. Is there a loss of system pressure? | Go to Step 8 | Go to Step 6 |
| 6 | Inspect for a faulty engine coolant temperature (ECT) sensor. Refer to DTC P0117 and DTC P0118 in Engine Controls - 4.8L, 5.3L, and 6.0L. Is the sensor operating properly? | Go to Step 7 | Go to Step 8 |
| 7 | Inspect for the following: Damaged coolant surge tank Leaking hose Bad/incorrect surge tank or radiator cap Were any of the above found? | Go to Step 8 | Go to Step 10 |
| 8 | Repair or install new parts as necessary, then retest. Does the engine overheat? | Go to Step 9 | System OK |
| 9 | Inspect for incorrect drive belt tension. Is the belt tension correct? | Go to Step 10 | Go to Step 8 |
| 10 | Remove the water pump. Refer to Water Pump Replacement (4.3L Engine) or Water Pump Replacement (4.8L, 5.3L, and 6.0L Engines) . Inspect for a damaged water pump shaft/hub. Is the water pump driveshaft damaged or is the seal leaking? | Go to Step 8 | Go to Step 11 |
| 11 | Inspect for obstructed radiator air flow or bent radiator fins. Is the radiator air flow obstructed? | Go to Step 8 | Go to Step 12 |
| 12 | Inspect for blocked cooling system passages. Are the cooling system passages blocked? | Go to Step 8 | Go to Step 13 |
| 13 | Inspect for inoperative fan clutch. Refer to Fan Clutch Diagnosis . Is the fan clutch operating correctly? | Go to Step 14 | Go to Step 8 |
| 14 | Inspect the thermostat. Refer to Thermostat Diagnosis . Is the thermostat stuck in the closed position? | Go to Step 15 | Go to Step 16 |
| 15 | Replace the thermostat. Refer to Thermostat Housing Replacement . Does the engine overheat? | Go to Step 16 | System OK |
| 16 | Inspect the radiator cooling capacity. Is the proper sized radiator being used on the vehicle? | Go to Step 3 | Go to Step 17 |
| 17 | Consult the current parts catalog and replace the radiator. Refer to Radiator Replacement . Is the repair complete? | System OK |
Engine Overheating
Loss of Coolant
| Step | Action | Yes | No |
|---|---|---|---|
| DEFINITION: The cooling system is loosing 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 System Check - Vehicle in Vehicle DTC Information. 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 . Is the action complete? | Go to Step 5 | |
| 5 | If the engine is suspected to have a coolant leak into the cylinder, the coolant can hydraulically lock the cylinder. Does the engine crankshaft rotate? | Go to Step 6 | Go to Step 30 |
| 6 | Engine overheating can cause a loss of coolant. Is the engine overheating? | Go to Step 31 | Go to Step 7 |
| 7 | Extended engine operation with a low coolant level can cause engine internal component failure. Is the engine knocking? | Go to Step 33 | 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 32 | 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: Auxiliary heater Coolant bypass Coolant crossover Coolant reservoir Heater Hot water shut-off valve Radiator Are any of the hoses, clamps, or pipes leaking? | Go to Step 21 | Go to Step 12 |
| 12 | Visually inspect the following components: Coolant pressure cap Coolant reservoir Core plugs Cylinder head gaskets Engine block Hot water shut-off valve Intake manifold Radiator Thermostat Water pump Are any of the listed components leaking? | Go to Step 21 | Go to Step 13 |
| 13 | Pressure test the cooling system. Refer to Cooling System Leak Testing . Visually inspect the components listed in steps 11 and 12 again. Are any leaks present? | Go to Step 21 | 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 22 |
| 15 | Pressure test the coolant pressure cap. Refer to Pressure Cap Testing . Does the coolant pressure cap hold pressure? | Go to Step 34 | Go to Step 22 |
| 16 | Inspect for the following conditions: A coolant smell inside of the vehicle Coolant in the HVAC module drain tube Coolant on the vehicles floor covering under the HVAC module Is coolant present? | Go to Step 23 | Go to Step 17 |
| 17 | If equipped with auxiliary heating, inspect for the following: A coolant smell inside of the vehicle Coolant in the auxiliary HVAC module drain tube Coolant on the floor covering near the auxiliary HVAC module Is coolant present? | Go to Step 24 | Go to Step 18 |
| 18 | Inspect the underside of the oil fill cap for a gray/white milky substance. Is there a milky substance under the oil fill cap? | Go to Step 19 | Go to Step 20 |
| 19 | 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 25 | Go to Step 20 |
| 20 | 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 27 | Go to Step 35 |
| 21 | Repair or replace the leaking component. Refer to the appropriate repair. Is the repair complete? | Go to Step 35 | |
| 22 | Replace the coolant pressure cap. Is the repair complete? | Go to Step 35 | |
| 23 | Replace the heater core. Refer to Heater Core Replacement in Heating, Ventilation and Air Conditioning. Is the repair complete? | Go to Step 35 | |
| 24 | Replace the auxiliary heater core. Refer to Heater Core Replacement - Auxiliary in Heating, Ventilation and Air Conditioning. Is the repair complete? | Go to Step 35 | |
| 25 | Remove the engine oil cooler lines from the radiator. Pressure test the cooling system. Refer to Cooling System Leak Testing . Inspect the engine oil cooler for coolant. Is coolant present in the engine oil cooler? | Go to Step 26 | Go to Step 29 |
| 26 | Replace the radiator. Refer to Radiator Replacement . Service the engine oil and filter. Refer to Engine Oil and Oil Filter Replacement in Engine Mechanical. Is the repair complete? | Go to Step 35 | |
| 27 | 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 in the transmission oil cooler? | Go to Step 28 | Go to Step 29 |
| 28 | Replace the radiator. Refer to Radiator Replacement . Service the automatic transmission. Refer to Engine Coolant/Water in Transmission in Automatic Transmission - 4L60-E or Engine Coolant/Water in Transmission in Automatic Transmission - 4L80-E. Is the repair complete? | Go to Step 35 | |
| 29 | Install the cooler lines to the radiator. Is the action complete? | Go to Step 35 | |
| 30 | Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate in Engine Mechanical. Is the repair complete? | Go to Step 35 | |
| 31 | Repair the engine overheating condition. Refer to Engine Overheating . Is the repair complete? | Go to Step 35 | |
| 32 | Repair the engine internal coolant leak. Refer to Coolant in Combustion Chamber or Coolant in Engine Oil in Engine Mechanical. Is the repair complete? | Go to Step 35 | |
| 33 | Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed in Engine Mechanical. Is the repair complete? | Go to Step 35 | |
| 34 | Repair the combustion pressure in the cooling system problem. Refer to Cylinder Leakage Test in Engine Mechanical. Is the repair complete? | Go to Step 35 | |
| 35 | 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
Coolant Heater Inoperative
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Engine Cooling |
| 2 | Test the engine coolant heater power supply cord for an open or short to ground. Refer to Circuit Testing in Wiring Systems. Did you find a condition? | Go to Step 3 | Go to Step 4 |
| 3 | Replace the engine coolant heater power supply cord. Refer to Coolant Heater Cord Replacement . Did you complete the repair? | Go to Step 6 | |
| 4 | Inspect for poor connections at the harness connector of the engine coolant heater. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 6 | Go to Step 5 |
| 5 | Replace the engine coolant heater. Refer to Coolant Heater Replacement (4.3L) or Coolant Heater Replacement (4.8L, 5.3L, and 6.0L) . Did you complete the repair? | Go to Step 6 | |
| 6 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
Coolant Heater Inoperative
Engine Fails To Reach Normal Operating Temperature
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the Symptoms-Engine Cooling diagnostic information and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Engine Cooling |
| 2 | Verify that the engine does not reach normal operating temperature. Does the engine reach normal operating temperature? | System OK | Go to Step 3 |
| 3 | Inspect the coolant level. Is the coolant level below the add mark? | Go to Step 4 | Go to Step 5 |
| 4 | Add coolant as necessary. Perform a cooling system pressure test. Does the cooling system hold pressure? | System OK | Go to Step 5 |
| 5 | Inspect for a stuck open, missing, or incorrect thermostat. Refer to Thermostat Diagnosis . Is the thermostat operating properly? | System OK | Go to Step 6 |
| 6 | Install the correct replacement thermostat. Refer to Thermostat Housing Replacement Is the repair complete? | Go to Step 7 | |
| 7 | Run the engine in order to verify the repair. Does the engine fail to reach normal operating temperature? | System OK |
Engine Fails To Reach Normal Operating Temperature
Looseness
If the fan assembly is loose, inspect the fan assembly for wear. Replace the fan assembly as necessary.
Observe the tip of the fan blade for lateral movement. Lateral movement occurs under various temperature conditions. A lateral movement measuring 6.5 mm (1/4 in) is normal. This amount of movement is not cause for replacement of the assembly.
Note. Check for adequate clearance between the fan blades and the thermometer sensor before starting the engine, as damage could occur.
Use the following procedure in order to diagnose the causes of engine overheating
- Ensure that the engine is cool. This will allow complete disengagement of the fan clutch.
- Spin the fan and clutch assembly by hand. If the fan and clutch assembly easily revolves more than 5 times with no drag, replace the fan clutch.
- If the fan clutch performs correctly but exhibits drag, position a thermometer between the fan blades and the radiator. Use any of the following methods in order to position the thermometer: Insert the thermometer sensor through one of the existing holes in the fan shroud. Place the thermometer between the radiator and the shroud. On models that do not have holes in the fan shroud, drill a 5 mm (3/16 in) hole in the fan shroud. Insert the thermometer in the hole.
- Cover the radiator in order to induce a high engine temperature.
- Start the engine.
- Turn on the air conditioning.
- Operate the engine at 2,000 RPM.
- Wait for 5 to 10 minutes while the temperature increases sufficiently to allow the fan clutch to engage. The following conditions indicate that the fan clutch has engaged: A roaring noise or an increase in fan noise occurs. The thermometer reading drops approximately 3-10°C (5-15°F).
- Observe the thermometer reading when the fan clutch engages. The following conditions are cause for replacement of the fan clutch: The fan clutch does not engage while the temperature measures 65-90°C (150-195°F). If the fan clutch does not engage while the temperature is within this range, verify that the fan clutch was disengaged at the beginning of the test. Both of the following conditions exist: No temperature drop occurs The fan noise level is constant from the beginning of the test until the time when the engine temperature reaches 88°C (190°F). Do not continue the test past a thermometer reading of 88°C (190°F) in order to prevent overheating.
- Perform the following steps as soon as the fan clutch engages: Remove the radiator cover. Turn OFF the air conditioning. Operate the engine at approximately 1,500 RPM until the coolant returns to the normal operating temperature.
- Observe the operation of the fan clutch. The fan clutch should disengage after several minutes. Disengagement of the fan clutch is indicated by a decrease in fan noise or roar. If the fan clutch does not disengage after several minutes, the fan clutch should be replaced.
Tools Required
- J 26568 Coolant and Battery Tester. See «Special Tools»(ref-197849-S10591011172005101300000) .
- J 38185 Hose Clamp Pliers
Filling Procedure
- Connect the lower radiator hose.
- Using the J 38185 position the clamp into the original position on the hose.
- If the engine block drain plug was removed, perform the following: Apply pipe sealer to the drain plug. Install the drain plug. Tighten: Tighten the drain plug to 22 N.m (16 lb ft).
- Lower the vehicle.
- Using the J 38185 , position the upper radiator hose clamp at the radiator.
- Remove the upper radiator hose from the radiator.
- Remove the coolant air bleed hose from the radiator.
- Place a funnel into the upper radiator hose.
- Slowly fill the cooling system through the upper radiator hose with a 50/50 coolant mixture until the coolant comes out the coolant air bleed hose. Refer to «Capacities - Approximate Fluid»(ref-197867-S33186411622005101300000) in General Information.
- Connect the upper radiator hose to the radiator.
- Using the J 38185 position the radiator hose clamp into the original position on the hose.
- Connect the coolant air bleed hose to the radiator.
- Fill the radiator with coolant through the filler neck.
- Install the coolant pressure cap.
- Fill the coolant overflow bottle to the full line.
- Start the engine.
- Run the engine at 2,000-2,500 RPM until the engine reaches normal operating temperature.
- Allow the engine to idle for 3 minutes.
- Shut the engine OFF.
- Allow the engine to cool.
- Top off the coolant as necessary.
- Inspect the concentration of the engine coolant, using the J 26568 . See «Special Tools»(ref-197849-S10591011172005101300000) .
- Rinse away any excess coolant from the engine and the engine compartment.
- Inspect the cooling system for leaks.
Radiator Cleaning
An engine will overheat if the radiator has any of the following conditions
- Leaks
- Dirt or obstructions in the core
Use a soft bristle brush and clean hot water or a mild detergent solution in order to clean the outside of the radiator core. A car wash or dishwashing liquid is a suitable detergent.
A common city water hose may also be used in order to clean the outside of the radiator. Remove the nozzle from the hose prior to use in order to prevent damage to the fins.
Use one of the following solutions in order to pressure flush and clean the inside of the core tubes
- Clean hot water
- Mild car wash
- Dishwashing liquid
Use the following steps in order to test the radiator for restrictions
- Warm the engine.
- Turn off the engine.
- Feel the radiator. The radiator should be hot along the left side and warm along the right side. There should be an even temperature rise from right to left. Cold spots in the radiator indicate clogged sections. Refer to «Cooling System Description and Operation»(ref-197849-S14375406892005101300000) for a radiator diagram.
J 38185 Hose Pliers
J 38185 Hose Clamp Pliers
J 41240 Fan Clutch Remover and Installer
J 41240 Fan Clutch Remover and Installer
J 41240 Fan Clutch Remover and Installer
J 38185 Hose Clamp Pliers
Coolant Heater
The optional engine coolant heater (RPO KO5) is designed to warm the coolant in the engine block area for improved starting in very cold weather (temperatures below -29°C (-20°F)). The coolant heater helps reduce fuel consumption when a cold engine is warming up. The engine coolant heater operates using AC external power and a heating element installed in the water jacket of the engine block. The heating element warms the coolant when the heater cord is plugged into an AC power source.
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 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.
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.
Some engine applications, coolant is also directed to the throttle body. There it circulates through passages in the casting. The coolant assists in regulating the throttle body temperature.
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 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 cross-flow 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 left 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.
During vehicle use, the coolant is heated and expands. The increased coolant volume flows into the surge tank. As the coolant circulates, any air is allowed to bubble out. Coolant without air bubbles absorbs heat much better than coolant with bubbles.
Coolant Recovery System
The coolant recovery system consists of a plastic coolant recovery reservoir, an overflow tube, and a pressure cap on the radiator. The recovery reservoir is also called a recovery tank or expansion tank. It is partially filled with coolant and is connected to the radiator fill neck with the overflow tube. Coolant can flow back and forth between the radiator and the reservoir.
In effect, a cooling system with a coolant recovery reservoir is a closed system. When the pressure in the cooling system gets too high, it will open the pressure valve in the pressure cap. This allows the coolant, which has expanded due to being heated, to flow through the overflow tube and into the recovery reservoir. As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum opens the vacuum valve in the pressure cap, allowing some of the coolant in the reservoir to be siphoned back into the radiator. Under normal operating conditions, no coolant is lost. Although the coolant level in the recovery reservoir goes up and down, the radiator and cooling system are kept full. An advantage to using a coolant recovery reservoir is that it eliminates almost all air bubbles from the cooling system. Coolant without air bubbles absorbs heat much better than coolant with bubbles.
Pressure Cap
The pressure cap seals the cooling system. It contains a blow off or pressure relief 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.
Cooling Fan and Clutch
The engine cooling fan and clutch are driven by the crankshaft via the drive belt. The cooling fan draws air through the radiator to improve the transfer of heat from the coolant to the atmosphere. As the fan blades spin, they pull cool, outside air past the radiator core. The fan clutch drives the cooling fan. The fan clutch controls the amount of torque that is transmitted from the crankshaft to the fan blades. The clutch allows more torque to engage on the fan when the engine operating temperature increases and/or the vehicle speed is low. As the torque increases, the fan turns more quickly. The fan clutch decreases the torque applied to the cooling fan when the engine temperature decreases and/or the vehicle speed is high. As the torque decreases, the fan speed decreases.
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, a retaining plate, pulley 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 drive belt.
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 a 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 85°C (185°F) for diesel engines and below 91°C (195°F) for gas engines, the thermostat valve remains closed. This prevents circulation of the coolant from the radiator and allows the engine to warm up. After the coolant temperature reaches 85°C (185°F) or 91°C (195°F), the thermostat valve will open. The coolant is then allowed to circulate through the thermostat to the engine and then 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.
Engine Oil Cooler
The engine oil cooler is a heat exchanger. It is located inside the left side end tank of the radiator. The engine oil temperature is controlled by the temperature of the engine coolant that surrounds the oil cooler in the radiator.
The engine oil pump pumps the oil through the engine oil cooler line to the oil cooler. The oil then flows through the cooler where the engine coolant absorbs heat from the oil. The oil is then pumped through the oil cooler return line, to the oil filter, to the engine block oil system.
Transmission Oil Cooler
The transmission oil cooler is a heat exchanger. It is located inside the right 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.