Engine Cooling System Diagnosis: Other Dodge Pickup R2500

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 14)

Scheme 14

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 the 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.

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 owner's 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 Charts ( (Scheme 15) - (Scheme 20).

The following charts are to be used as a quick-reference only. (Scheme 15)- (Scheme 20).

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

STANDARD PROCEDURE - COOLANT LEVEL CHECK

Note. DO NOT remove radiator cap for routine coolant level inspections. The coolant level can be checked at coolant recovery bottle or the coolant degas bottle.

The 5.9L, 5.9L Diesel, and 8.0L engine 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.

The 3.7L/4.7L/5.9L engine coolant degas system provides a quick method for determining the coolant level without removing the radiator pressure cap. With a cold engine, observe the level of coolant in the degas bottle. The level should be in the COLD FILL RANGE. DO NOT OVERFILL the bottle by adding fluid above the COLD FILL RANGE. This may cause coolant to spill onto the ground during subsequent vehicle operation.

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.

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.

STANDARD PROCEDURE - 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.

For 5.9L engines, 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.

For 3.7L / 4.7L/5.9L engines, remove the radiator cap from the coolant degas bottle to add coolant.