Engine Cooling System & Automatic Transmission Cooling System: Maintenance Jeep Commander I

CLEANING/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 fittings. Attach a section of 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 radiator is filled, apply air in short blasts allowing radiator to refill between blasts. Continue this reverse flushing until clean water flows out through rear of radiator cooling tube passages. For more information, refer to operating instructions supplied with flushing equipment. Have radiator cleaned more extensively by a radiator repair shop.

REVERSE FLUSHING ENGINE

Drain the cooling system. See STANDARD PROCEDURE . 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. Attach a lead away hose to the water pump inlet fitting.

Connect the water supply hose and air supply hose to the 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. For more information, refer to operating instructions supplied with flushing equipment.

Remove the lead away hose, flushing gun, water supply hose and air supply hose. Remove the thermostat housing. See REMOVAL . Install the thermostat and housing with a replacement gasket. See INSTALLATION . Connect the radiator hoses. Refill the cooling system with the correct antifreeze/water mixture. See STANDARD PROCEDURE .

RADIATOR COOLING FAN HYDRAULIC FLUID PATH

Hydraulic fluid is pumped through the power steering pump, from the pump the fluid travels though a high pressure delivery line to the fan drive motor. As fluid is diverted through the G-rotors, rotational motion is created as fluid moves from the high-pressure (inlet) side of the motor to the low-pressure (outlet) side. Fluid exiting the drive motor is divided into two paths. Path one continues through a high pressure delivery line to the vehicles steering gear to provide steering assist and path two sends fluid back to the power steering pump through a low pressure line. Fluid exits the steering gear under low pressure and travels through a low pressure line to the power steering fluid cooler to be cooled before being returned back the power steering fluid reservoir.

Note. There is a steering flow control valve located in the fan drive motor. This valve operates like the flow control valve found in the typical power steering pump. Because of the design of the valve steering assist can not be effected by the radiator cooling fan even during fan drive failure.

Scheme 45

Scheme 46

Scheme 47

1. Raise vehicle on hoist.
2. Drain cooling system. See «STANDARD PROCEDURE»(ref-288235-S07920148752008062000000). NOTE: The hydraulic fan drive is driven by the power steering pump. When removing lines or hoses from fan drive assembly use a drain pan to catch any power steering fluid that may exit the fan drive or the lines and hoses. NOTE: When ever the high pressure line fittings are removed from the hydraulic fan drive the O-rings must be replaced.
3. Disconnect two high pressure lines at hydraulic fan drive. (Scheme 45) Remove and discard o-rings from line fittings.
4. Disconnect low pressure return hose at hydraulic fan drive. (Scheme 45) NOTE: The lower mounting bolts can only be accessed from under vehicle.
5. Remove two lower mounting bolts from the shroud. (Scheme 47)
6. Lower vehicle.
7. Disconnect the electrical connector for the fan control solenoid.
8. Disconnect the radiator upper hose at the radiator and position out of the way. 1 - POWER STEERING COOLER RETURN HOSE 2 - POWER STEERING COOLER SUPPLY HOSE
9. Disconnect the power steering gear outlet hose and fluid return hose at the cooler. (Scheme 46) 1 - FAN SHROUD UPPER MOUNTING BOLT LOCATIONS 2 - WIRE HARNESS RETAINER
10. Remove two upper mounting bolts from the shroud.
11. Remove the shroud and fan drive from vehicle.