Isuzu KB P190. Manual - part 238

6B – 8  ENGINE COOLING 

 

 

Draining and Refilling Cooling System 

Before draining the cooling system, inspect the system and
perform any necessary service to ensure that it is clean, does
not leak and is in proper working order.   The engine coolant 
(EC) level should be between the “MIN" and “MAX" lines of
reserve tank when the engine is cold. If low, check for leakage
and add EC up to the “MAX" line. 
There should not be any excessive deposit of rust or scales
around the radiator cap or radiator filler hole, and the EC 
should also be free from oil. 
Replace the EC if excessively dirty. 
 

 

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1.  Completely drain the cooling system by opening the drain

plug at the bottom of the radiator. 

 

 

 

2.  Remove the radiator cap. 

WARNING: To avoid the danger of being burned, do not
remove the cap while the engine and radiator are still hot.
Scalding fluid and steam can be blown out under
pressure. 
3.  Disconnect all hoses from the EC reserve tank. 

 

Scrub and clean the inside of the reserve tank with soap 

and water. Flush it well with clean water, then drain it.

Install the reserve tank and hoses. 

4.  Refill the cooling system with the EC using a solution that is

at least 50 percent antifreeze. 

 
Procedure for filling with coolant (in case of full change) 
•  Make sure that the engine is cool. 
•  Open radiator cap pour coolant up to filler neck. 
•  Pour coolant into reservoir tank up to “MAX" line. 
•  Tighten radiator cap and start the engine. After idling for 2

to 3 minutes, stop the engine and reopen radiator cap. If the 

water level is lower, replenish. 

WARNING: When the coolant is heated to a high
temperature, be sure not to loosen or remove the radiator
cap. Otherwise you might get scalded by not vapor or
boiling water. To open the radiator cap, put a piece of 
thick cloth on the cap and loosen the cap slowly to reduce
the pressure when the coolant has become cooler. 
 

ENGINE COOLING   6B – 9 

 

 

•  After tightening radiator cap, warm up the engine at about

2000 rpm. Set heater adjustment to the highest temperature 

position, and let the coolant circulate also into heater water

system. 

•  Check to see the thermostat has opened through the

needle position of water thermometer, conduct a 5–minute 

idling again and stop the engine. 

•  When the engine has been cooled, check filler neck for 

water level and replenish if required. Should extreme

shortage of coolant is found, check the cooling system and

reservoir tank hose for leakage. 

•  Pour coolant into the reservoir tank up to “MAX" line. 
 

6B – 10  ENGINE COOLING 

 

WATER PUMP 

  

 REMOVAL AND INSTALLATION 

Read this Section carefully before performing any removal and installation procedure. This Section gives you 
important points as well as the order of operation. Be sure that you understand everything in this Section before you 
begin. 
 

 

 

 

Removal 

1.  Radiator Upper Hose 

1)  Partially drain the engine coolant. 

2)  Remove the radiator upper hose. 

 

 

  

 

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2.  Water Outlet Pipe 

1)  Disconnect the turbocharger-cooling pipe from outlet 

pipe. 

2)  Loosen the fixing bolt and remove the water outlet 

bolt. 

3. Thermostat 

Remove the thermostat from the thermostat housing. 

Take care not to damage the thermostat. 

4.  Upper Fan Shroud 

 

 

5.  Fan and Fan Clutch 

1)  Loosen the fan clutch nuts. 

2)  Remove the fan together with the fan clutch. Take 

care not to damage the radiator core. 

6.  Fan Drive Belt and Pulley 

1)  Loosen the tension adjust bolt on the generator. 

2)  Remove the fan drive belt with the fan pulley. 

 

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7. Water 

Pump 

1)  Remove the water pump bolts. 

2)  Remove the water pump. 

 

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ENGINE COOLING   6B – 11 

 

Inspection and Repair 

The water pump is not disassembled type. 

Make necessary parts replacement if extreme wear or 
damage is found during inspection. Should any of the 
following problems occur, the entire water pump assembly 
must be replaced. 

・  Cracks in the water pump body 
・  Coolant leakage from the seal unit 
・  Excessive radial play or abnormal noise in the fan center 

when rotate by hand 

・  Excessive thrust play in the fan center (Standard play: less 

than 0.2mm) 

・  Cracks or corrosion in the impeller 

 
 
 
 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Installation 

1. Water 

Pump 

1)  Install the water pump with new gasket. 

2)  Tighten bolts and nuts to specified torque. 

Water Pump Bolt/Nut Torque 

N·m(kg·m/lb ft)

20 (2.0/14) 

 

2.  Fan Drive Belt and Pulley 

1)  Install the fan drive belt and fan pulley. 

2)  Apply tension to the fan drive belt by moving the 

generator. 

3)  Apply a force of 98N(10kg/22 lb) to the drive belt mid-

portion to check the drive belt deflection. 

Fan Drive Belt Deflection 

mm (in)

New belt: 4-7(0.16-0.28) 

Reuse belt: 6-9(0.24-0.35) 

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3.  Fan and Fan Clutch 

1)  Install the fan and fan clutch to pulley. 

2)  Tighten the nuts to specified torque. 

Fan Clutch Nut Torque 

N·m(kg·m/lb in)

8(0.8/69) 

 

4.  Upper Fan Shroud