Engine Cooling System - Diagnosis, Servicing, Specifications Dodge Pickup R1500

GAS ENGINE

The cooling system regulates engine operating temperature. It allows the engine to reach normal operating temperature as quickly as possible. It also maintains normal operating temperature and prevents overheating.

The cooling system provides a means of heating the passenger compartment and cooling the automatic transmission fluid (if equipped). The cooling system is pressurized and uses a centrifugal water pump to circulate coolant through the system. The coolant recovery/reserve system utilizes an ambient overflow bottle.

An optional factory installed maximum duty cooling package is available on most models. This package will provide additional cooling capacity for vehicles used under extreme conditions such as trailer towing in high ambient temperatures.

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5.9L DIESEL

The diesel engine cooling system consists of

1. Cross-flow radiator
2. Belt driven water pump
3. Cooling fan (attached to the electronic viscous fan drive)
4. Belt driven Electronic viscous fan drive
5. Two piece fan shroud
6. Radiator pressure cap
7. Vertically mounted thermostat
8. Coolant reserve/recovery system
9. Transmission oil cooler
10. Coolant

Coolant flow circuits for the 5.9L diesel engine are shown in (Scheme 16)

Scheme 16

DESCRIPTION - HOSE CLAMPS

The cooling system utilizes spring type hose clamps. If a spring type clamp replacement is necessary, replace with the original Mopar® equipment spring type clamp.

Scheme 17

OPERATION - COOLING SYSTEM

The cooling system regulates engine operating temperature. It allows the engine to reach normal operating temperature as quickly as possible. It also maintains normal operating temperature and prevents overheating.

The cooling system also provides a source of hot water (coolant) for heating the passenger compartment and cooling the automatic transmission fluid (if equipped). The cooling system is pressurized and uses a centrifugal water pump to circulate coolant throughout the system.

1. When engine is cold the thermostat is closed. The cooling system has no flow through the radiator. The coolant flows through the engine, water pump, and heater.
2. When engine is warm the thermostat is full open. The coolant flows through the radiator, heater, and water pump.

All engines utilize an ambient overflow bottle for coolant recovery/reserve.

An optional factory installed maximum duty cooling package is available on most models. This package will provide additional cooling capacity for vehicles used under extreme conditions such as trailer towing in high ambient temperatures.

OPERATION - HOSE CLAMPS

The spring type hose clamp applies constant tension on a hose connection. To remove a spring type hose clamp, only use constant tension clamp pliers designed to compress the hose clamp.

COOLING SYSTEM RELATED DIAGNOSTICS

The Engine Control Module (ECM) has been programmed to monitor certain cooling system components

1. If the engine has remained cool for too long a period, such as with a stuck open thermostat, a Diagnostic Trouble Code (DTC) can be set.
2. If an open or shorted condition has developed in the electronically controlled viscous fan clutch circuit, a Diagnostic Trouble Code (DTC) can be set.
3. If fan speed is not detected a DTC will be set.
4. Coolant temperature sensor circuit problems can set a DTC.

If the problem is sensed in a monitored circuit often enough to indicated an actual problem, a DTC is stored. The DTC will be stored in the ECM memory for eventual display to the service technician. (Refer to EMISSIONS CONTROL ).

ACCESSING DIAGNOSTIC TROUBLE CODES

To read DTC's and to obtain cooling system data, (Refer to EMISSIONS CONTROL ).

ERASING TROUBLE CODES

After the problem has been repaired, use the DRBIII® scan tool to erase a DTC. Refer to POWERTRAIN DIAGNOSTIC PROCEDURES (PART 1) for operation of the DRBIII® scan tool.

ULTRAVIOLET LIGHT METHOD

A leak detection additive is available through the parts department that can be added to cooling system. The additive is highly visible under ultraviolet light (black light). Pour one ounce of additive into cooling system. Place heater control unit in HEAT position. Start and operate the engine until the radiator upper hose is warm to the touch. Aim the commercially available black light tool at the components to be checked. If leaks are present, the black light will cause the additive to glow a bright green color.

The black light can be used in conjunction with a pressure tester to determine if any external leaks exist (Scheme 18)

Scheme 18

PRESSURE TESTER METHOD

The engine should be at normal operating temperature. Recheck the system cold if the cause of coolant loss is not located during the warm engine examination.

Carefully remove the radiator pressure cap from the filler neck and check the coolant level. Push down on the cap to disengage it from the stop tabs. Wipe the inside of the filler neck and examine the lower inside sealing seat for nicks, cracks, paint, dirt and solder residue. Inspect the radiator-to-reserve/overflow tank hose for internal obstructions. Insert a wire through the hose to be sure it is not obstructed.

Inspect the cams on the outside of the filler neck. If the cams are damaged, seating of the pressure cap valve and tester seal will be affected.

Attach pressure tester (7700 or an equivalent) to radiator filler neck.

Operate the tester pump to apply 103.4 kPa (15 psi) pressure to the system. If the hoses enlarge excessively or bulges while testing, replace as necessary. Observe the gauge pointer and determine the condition of the cooling system according to following criteria

Holds Steady: If the pointer remains steady for two minutes, serious coolant leaks are not present in system. However, there could be an internal leak that does not appear with normal system test pressure. If it is certain that coolant is being lost and leaks cannot be detected, inspect for interior leakage or perform Internal Leakage Test. Refer to INTERNAL LEAKAGE INSPECTION .

Drops Slowly: Indicates a small leak or seepage is occurring. Examine all of the connections for seepage or slight leakage with a flashlight. Inspect the radiator, hoses, gasket edges and heater. Seal the small leak holes with a Sealer Lubricant (or equivalent). Repair the leak holes and inspect the system again with pressure applied.

Drops Quickly : Indicates that serious leakage is occurring. Examine the system for external leakage. If leaks are not visible, inspect for internal leakage. Large radiator leak holes should be repaired by a reputable radiator repair shop.

INTERNAL LEAKAGE INSPECTION

Remove the engine oil pan drain plug and drain a small amount of engine oil. If coolant is present in the pan, it will drain first because it is heavier than oil. An alternative method is to operate engine for a short period to churn the oil. After this is done, remove the engine dipstick and inspect for water globules. Also inspect the transmission dipstick for water globules and transmission fluid cooler for leakage.

Operate the engine without the pressure cap on the radiator until the thermostat opens. Attach a Pressure Tester to the filler neck. If pressure builds up quickly it indicates a combustion leak exists. This is usually the result of a cylinder head gasket leak or crack in engine. Repair as necessary.

If there is not an immediate pressure increase, pump the Pressure Tester. Do this until indicated pressure is within system range of 110 kPa (16 psi). Fluctuation of the gauge pointer indicates compression or combustion leakage into cooling system.

Because the vehicle is equipped with a catalytic converter, do not short out cylinders to isolate compression leak.

If the needle on dial of the pressure tester does not fluctuate, race engine a few times to check for an abnormal amount of coolant or steam. This would be emitting from exhaust pipe. Coolant or steam from exhaust pipe may indicate a faulty cylinder head gasket, cracked engine cylinder block or cylinder head.

A convenient check for exhaust gas leakage into cooling system is provided by a commercially available Block Leak Check tool. Follow manufacturers instructions when using this product.

COMBUSTION LEAKAGE TEST - WITHOUT PRESSURE TESTER

DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

Drain sufficient coolant to allow thermostat removal. (Refer to ENGINE COOLANT THERMOSTAT ). Remove accessory drive belt (Refer to ACCESSORY DRIVE ).

Add coolant to radiator to bring level to within 6.3 mm (1/4 in) of the top of the thermostat housing.

Start engine and accelerate rapidly three times, to approximately 3000 RPM while observing coolant. If internal engine combustion gases are leaking into cooling system, bubbles will appear in coolant. If bubbles do not appear, internal combustion gas leakage is not present.

COOLING SYSTEM DIAGNOSIS - DIESEL ENGINE

COOLING SYSTEM DIAGNOSIS - DIESEL ENGINE

ENGINE COOLING SYSTEM OVERHEATING

Establish what driving conditions caused the complaint. Abnormal loads on the cooling system such as the following may be the cause

1. PROLONGED IDLE
2. VERY HIGH AMBIENT TEMPERATURE
3. SLIGHT TAIL WIND AT IDLE
4. SLOW TRAFFIC
5. TRAFFIC JAMS
6. HIGH SPEED OR STEEP GRADES

Driving techniques that avoid overheating are

1. Idle with A/C off when temperature gauge is at end of normal range.
2. Increasing engine speed for more air flow is recommended.

TRAILER TOWING

Consult Trailer Towing section of owners manual. Do not exceed limits.

RECENT SERVICE OR ACCIDENT REPAIR

Determine if any recent service has been performed on vehicle that may effect the cooling system. This may be

1. Engine adjustments (incorrect timing)
2. Slipping engine accessory drive belt(s)
3. Brakes (possibly dragging)
4. Changed parts. Incorrect water pump or pump rotating in wrong direction due to belt not correctly routed
5. Reconditioned radiator or cooling system refilling (possibly under filled or air trapped in system).
6. Service to electrically controlled viscous fan clutch

Note. If investigation reveals none of the previous items as a cause for an engine overheating complaint, refer to COOLING SYSTEM DIAGNOSIS CHART .

These charts are to be used as a quick-reference only. Refer to COOLING SYSTEM DIAGNOSIS CHART

COOLING SYSTEM DIAGNOSIS CHART

COOLING SYSTEM DIAGNOSIS

ADDING ADDITIONAL COOLANT

The use of aluminum cylinder blocks, cylinder heads and water pumps requires special corrosion protection. Only Mopar® Antifreeze/Coolant, 5 Year/100,000 Mile Formula (glycol base coolant with corrosion inhibitors called HOAT, for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% distilled water to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.

Do not remove the radiator cap to add coolant to the system. When adding coolant to maintain the correct level, do so only at the reserve/overflow bottle. Remove the radiator cap only for testing or when refilling the system after service. Removing the cap unnecessarily can cause loss of coolant and allow air to enter the system, which produces corrosion.

COOLANT LEVEL CHECK

Note. Do not remove radiator cap for routine coolant level inspections. The coolant level can be checked at coolant recovery bottle.

The coolant reserve/overflow system provides a quick method for determining the coolant level without removing the radiator pressure cap. With the engine at normal operating temperature and idling, observe the level of the coolant on the external level indicator on the side of the coolant reserve / overflow bottle. The coolant level should be between the MIN and MAX marks. If the coolant is below the MIN mark, add a 50/50 mixture of antifreeze and water to the bottle until the level reaches the MIN mark. Do Not Overfill the bottle by adding fluid above the MAX line. This may cause coolant to spill onto the ground during subsequent vehicle operation.

DRAINING COOLING SYSTEM - ALL GAS ENGINES

DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

Scheme 19

Scheme 20

1. Attach one end of a hose to the draincock. Put the other end into a clean container.
2. DO NOT REMOVE THE RADIATOR CAP when draining the coolant from the reservoir/overflow tank. Open radiator draincock and when the tank is empty, remove the radiator cap and continue draining the cooling system.
3. If draining the entire engine, remove the cylinder block drain plugs. (Scheme 19) or (Scheme 20)

REFILLING COOLING SYSTEM - ALL GAS ENGINES

DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

Clean cooling system prior to refilling. (Refer to STANDARD PROCEDURE ).

1. Install cylinder block drain plugs. Coat the threads with Mopar® Thread Sealant with Teflon.
2. Close radiator petcock.
3. Fill cooling system with a 50/50 mixture of water and antifreeze.
4. Fill coolant reserve/overflow tank to MAX mark on bottle.
5. Start and operate engine until thermostat opens (upper radiator hose warm to touch).
6. If necessary, add a 50/50 water and antifreeze mixture to the coolant reserve/overflow tank. This is done to maintain coolant level between the MAX and MIN marks. The level in the reserve/overflow tank may drop below the MIN mark after three or four warm-up and cool-down cycles.

DRAINING COOLING SYSTEM - SRT-10

DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

Scheme 21

1. Attach one end of a hose to the draincock. Put the other end into a clean container.
2. DO NOT REMOVE THE RADIATOR CAP when draining the coolant from the reservoir/overflow tank. Open radiator draincock and when the tank is empty, remove the radiator cap and continue draining the cooling system.
3. If draining the entire engine, remove the cylinder block drain plugs. (Scheme 21)

STANDARD PROCEDURE - REFILLING COOLING SYSTE - SRT-10

DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

1. Install cylinder block drain plugs. Coat the threads with Mopar® Thread Sealant with Teflon.
2. Close radiator petcock.
3. Fill cooling system with a 50/50 mixture of water and antifreeze.
4. Fill coolant reserve/overflow tank to MAX mark on bottle.
5. Start and operate engine until thermostat opens (upper radiator hose warm to touch).
6. If necessary, add a 50/50 water and antifreeze mixture to the coolant reserve/overflow tank. This is done to maintain coolant level between the MAX and MIN marks. The level in the reserve/overflow tank may drop below the MIN mark after three or four warm-up and cool-down cycles.

DRAINING COOLING SYSTEM 5.9L DIESEL ENGINE

DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

1. Start the engine and place the heater control temperature selector in the Full-On position.
2. Turn the ignition off.
3. Do not remove radiator cap when draining coolant from reserve/overflow tank. Open radiator drain plug and when tank is empty, remove radiator cap. If the coolant reserve/overflow tank does not drain, (Refer to «DIAGNOSIS AND TESTING»(/dodge/pickup-r1500/1997-2012/remont/cooling-system-mechanical/#engine-cooling-system-diagnosis-servicing-specifications) ). The coolant need not be removed from tank unless the system is being refilled with fresh mixture.
4. Remove radiator pressure cap.

REFILLING COOLING SYSTEM 5.9L DIESEL ENGINE

Clean cooling system prior to refilling (Refer to STANDARD PROCEDURE ).

1. Close radiator drain plug. CAUTION: Due to the use of the one-way check valve, the engine must not be operating when refilling the cooling system. NOTE: The diesel engine is equipped with two one-way check valves (jiggle pins). The check valves are used as a servicing feature and will vent air when the system is being filled. Water pressure (or flow) will hold the valves closed.
2. Fill the cooling system with a 50/50 mixture of water and antifreeze.
3. Fill coolant reserve/overflow tank to the FULL mark.
4. Start and operate engine until thermostat opens. Upper radiator hose should be warm to touch.
5. If necessary, add 50/50 water and antifreeze mixture to the coolant reserve/overflow tank to maintain coolant level. This level should be between the ADD and FULL marks. The level in the reserve/overflow tank may drop below the ADD mark after three or four warm-up and cool-down cycles.

CLEANING

Drain the cooling system and refill with water. Run the engine with the radiator cap installed until the upper radiator hose is hot. Stop the engine and drain the water from system. If the water is dirty, fill the system with water, run the engine and drain the system. Repeat this procedure until the water drains clean.

REVERSE FLUSHING

Reverse flushing of the cooling system is the forcing of water through the cooling system. This is done using air pressure in the opposite direction of normal coolant flow. It is usually only necessary with very dirty systems with evidence of partial plugging.

REVERSE FLUSHING RADIATOR

Disconnect the radiator hoses from the radiator inlet and outlet. Attach a sectien of the radiator hose to the radiator bottom outlet fitting and insert the flushing gun. Connect a water supply hose and air supply hose to the flushing gun.

Allow the radiator to fill with water. When the radiator is filled, apply air in short blasts. Allow the radiator to refill between blasts. Continue this reverse flushing until clean water flows out through the rear of the radiator cooling tube passages.

REVERSE FLUSHING ENGINE

Drain the cooling system. Remove the thermostat housing and thermostat. Install the thermostat housing. Disconnect the radiator upper hose from the radiator and attach the flushing gun to the hose. Disconnect the radiator lower hose from the water pump and attach a lead-away hose to the water pump inlet fitting.

Connect the water supply hose and air supply hose to flushing gun. Allow the engine to fill with water. When the engine is filled, apply air in short blasts, allowing the system to fill between air blasts. Continue until clean water flows through the lead away hose.

Remove the lead away hose, flushing gun, water supply hose and air supply hose. Remove the thermostat housing and install the thermostat. Install the thermostat housing with a replacement gasket. Refer to Thermostat Replacement. Connect the radiator hoses. Refill the cooling system with the correct antifreeze/water mixture. Refer to Refilling the Cooling System.

CHEMICAL CLEANING

In some instances, use a radiator cleaner (Mopar® Radiator Kleen or equivalent) before flushing. This will soften scale and other deposits and aid flushing operation.

TORQUE

TORQUE SPECIFICATIONS

SPECIFICATIONS - FILL VOLUMES

FILL VOLUMES SPECIFICATIONS

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Scheme 26

See also:
• EMISSIONS CONTROL
• POWERTRAIN DIAGNOSTIC PROCEDURES (PART 1)
• ENGINE COOLANT THERMOSTAT
• ACCESSORY DRIVE
• INTERNAL LEAKAGE INSPECTION
• STANDARD PROCEDURE
• COOLING SYSTEM DIAGNOSIS CHART