Engine Cooling System & Automatic Transmission Cooling System: Overview Dodge Magnum I рестайлинг

Scheme 6

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

The cooling system also provides a means of heating the passenger compartment. The cooling system is pressurized and uses a centrifugal water pump to circulate coolant throughout the system. A separate and remotely mounted, pressurized coolant tank using a pressure/vent cap is used.

COOLING-DESCRIPTION-GAS

The cooling system consists of

1. Radiator
2. Electric Cooling fan
3. Hydraulic Cooling Fan (Diesel Engine)
4. Fan shroud
5. Radiator pressure cap
6. Thermostat
7. Coolant reserve/overflow system
8. EGR Cooler (Diesel Engine)
9. Transmission oil cooler (if equipped with an automatic transmission)
10. Coolant
11. Water pump
12. Hoses and hose clamps

Scheme 7

Scheme 8

Scheme 9

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 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 throughout the system.

Scheme 10

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) (1). Pour one ounce of additive into cooling system. Place heater control unit in HEAT position. Start and operate engine until the radiator upper hose is warm to touch. Aim the commercially available black light tool at components to be checked. If leaks are present, 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 11

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 coolant level. Push down on cap to disengage it from the stop tabs. Wipe the inside of 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 cams on the outside of 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) (1) to radiator filler neck.

Operate tester pump to apply 124.1 kPa (18 psi) pressure to system. If hoses enlarge excessively or bulge 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 connections for seepage or slight leakage with a flashlight. Inspect radiator, hoses, gasket edges and heater. Seal small leak holes with a Sealer Lubricant (or equivalent). Repair leak holes and inspect system again with pressure applied.

Drops Quickly: Indicates that serious leakage is occurring. Examine 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.

DESCRIPTION

The accessory drive belt is a serpentine type belt. Satisfactory performance of these belts depends on belt condition and proper belt tension.

Scheme 12

When diagnosing serpentine accessory drive belts, small cracks (1) that run across the ribbed surface of the belt from rib to rib , are considered normal. These are not a reason to replace the belt. However, cracks (2) running along a rib (not across) are not normal. Any belt with cracks running along a rib must be replaced. Also replace the belt if it has excessive wear, frayed cords, severe glazing or chunking.

Any belt with bumps, surface coming apart, or any other uneven indications along the flat surface of the belt must be remove and inspected and replaced if necessary.

Refer to ACCESSORY DRIVE BELT DIAGNOSIS CHART for further belt diagnosis.

OPERATION

The automatic belt tensioner maintains belt tension by using internal spring pressure, a pivoting arm and pulley to apply force against the drive belt.

Scheme 13

On all engines, the tensioner (1) is equipped with an indexing tang on back of tensioner and an indexing stop on tensioner housing. If a new belt is being installed, tang must be within approximately 6 - 8mm (0.24 - 0.32 in.) of indexing stop (i.e. tang is approximately between the two indexing stops). Belt is considered new if it has been used 15 minutes or less.

If the above specification cannot be met, check for

1. The wrong belt being installed (incorrect length/width)
2. Worn bearings on an engine accessory (A/C compressor, power steering pump, water pump, idler pulley or generator)
3. Belt is not installed in pulley grooves
4. A pulley on an engine accessory being loose
5. Misalignment of an engine accessory
6. Belt incorrectly routed.

Note. A used belt should be replaced if tensioner indexing arrow has moved to the minimum tension indicator. Tensioner travel stops at this point.

1. Remove accessory drive belt. See «REMOVAL»(ref-304465-S33901878492008111000000) . WARNING: Because of high spring pressure, do not attempt to disassemble automatic tensioner. Unit is serviced as an assembly except for pulley on tensioner.
2. Remove tensioner assembly bolt (1).
3. Remove tensioner assembly (2) from mounting bracket.

Scheme 14

On all engines, the tensioner (1) is equipped with an indexing tang on back of tensioner and an indexing stop on tensioner housing. If a new belt is being installed, tang must be within approximately 6 - 8mm (0.24 - 0.32 in.) of indexing stop (i.e. tang is approximately between the two indexing stops). Belt is considered new if it has been used 15 minutes or less.

If the above specification cannot be met, check for

1. The wrong belt being installed (incorrect length/width)
2. Worn bearings on an engine accessory (A/C compressor, power steering pump, water pump, idler pulley or generator)
3. Belt is not installed in pulley grooves
4. A pulley on an engine accessory being loose
5. Misalignment of an engine accessory
6. Belt incorrectly routed.

Note. A used belt should be replaced if tensioner indexing arrow has moved to the minimum tension indicator. Tensioner travel stops at this point.

1. Remove accessory drive belt. See «REMOVAL»(ref-304465-S33901878492008111000000) . WARNING: Because of high spring pressure, do not attempt to disassemble automatic tensioner. Unit is serviced as an assembly except for pulley on tensioner.
2. Remove tensioner assembly bolt (2).
3. Remove tensioner assembly (1) from mounting bracket.

Coolant flows through the engine block absorbing the heat from the engine, then flows to the radiator where the cooling fins in the radiator transfers the heat from the coolant to the atmosphere. During cold weather the ethylene-glycol or propylene-glycol coolant prevents water present in the cooling system from freezing within temperatures indicated by mixture ratio of coolant to water.

When power is applied (110 volt AC) to the block heater, the heating element transfers heat through the aluminum engine block and into the coolant without directly penetrating the cooling system.

The engine cooling thermostats are a wax pellet driven, reverse poppet choke type. The thermostats have an air bleed located in the thermostat flange. The air bleed allows internal trapped air during cooling system filling to be released. The thermostat on the 2.7L and 3.5L engines are located on the lower left side of engine, near the front. The thermostat on both engines are on the inlet side of the water pump.

The thermostat on the 5.7L/6.1L gas powered engine is located beneath the thermostat housing (1) at the front of the intake manifold.

Scheme 15

The thermostat on the 3.0L Diesel engine is integrated into the thermostat housing located at the front of the right intake manifold and is serviced as an assembly. A rubber seal is used to seal the thermostat housing to the intake manifold. The thermostat contains the following components

1. Main Valve (4) - Controls coolant flow through the radiator
2. Bypass Valve (2) - Controls coolant flow through the bypass passage to the inlet side of the water pump
3. Vent Valve (1) - Vents the cooling system via a ball valve when it is filled and when the engine is running
4. Thermostat Housing Seal (3)

The engine cooling thermostat is a wax pellet driven, reverse poppet choke type. The thermostat is designed to provide the fastest warm up possible by preventing leakage through it and to guarantee a minimum engine operating temperature of 88 to 93° C (192 to 199° F). The thermostat also will automatically reach wide open so it will not restrict flow to the radiator as temperature of the coolant rises in hot weather to around 104° C (220° F). Above this temperature the coolant temperature is controlled by the radiator, fan, and ambient temperature, not the thermostat.

The thermostat is operated by a wax filled container (pellet) which is sealed. When heated coolant reaches a predetermined temperature, the wax expands enough to overcome the closing spring and water pump pressure, which forces the valve to open.

Scheme 16

Up to a coolant temperature of approximately 87° C (189° F), the main valve is closed and the bypass valve fully open. The flow through the radiator is interrupted and coolant flows through the bypass passage directly to the inlet side of the water pump.

Scheme 17

The main valve begins to open at a coolant temperature of 86° C (189° F), and a small amount of coolant flows through the radiator. As the engine temperature increases, the main valve opens further and the bypass valve gradually closes. More coolant flows through the radiator and less coolant flows through the bypass passage.

Scheme 18

The main valve is fully open at a coolant temperature above 102° C (216° F). The bypass plate seals off the bypass passage. The entire quantity of coolant flows through the radiator.

A vent valve in the center of the cap will remain shut as long as the cooling system is pressurized. As the coolant cools, it contracts and creates a vacuum in cooling system. This causes the vacuum valve to open and coolant in reserve/overflow tank to be drawn through connecting hose into radiator. If the vacuum valve is stuck shut, or overflow hose is kinked, radiator hoses will collapse on cool-down.

THERMO BYPASS VALVE-DESCRIPTION

The transmission thermal bypass valve is mounted on LH side of the engine at the A/C compressor.

THERMO BYPASS VALVE-OPERATION

The air-to-oil transmission cooler system has thermal bypass valve assembly that controls fluid flow through the cooler. When the transmission fluid is cold (less then operating temperature), the fluid is routed through the cooler bypass valve without flowing through the transmission cooler. When the transmission fluid reaches operating temperatures 71°C (160°F) and above, the thermostat closing off the bypass and allowing fluid to flow through the transmission cooler. The thermal bypass valve is serviced as an assembly.

Scheme 19

1. Raise and support vehicle.
2. Remove front transmission cooler lines from the thermal bypass valve block (2).
3. Remove rear transmission cooler lines from the thermal bypass valve block (2).
4. Remove thermal bypass valve block (2).