Isuzu KB P190. Service manual - part 527

6B-4  ENGINE COOLING 

 

 

 

Antifreeze Solution 

•  Calculating mixing ratio 
Mixing ratio 
 
=  

Antifreeze solution (Lit/gal.) 

Antifreeze solution (Lit/gal.) + Water (Lit/gal.) 

 

NOTE: Antifreeze solution + Water = Total cooling system 
capacity. 

•  Total Cooling System Capacity 
8Lit 

 

 

 

 

•  Mixing ratio  
  Check the specific gravity of engine coolant in the cooling

system temperature ranges from 0

°C to 50°C using a 

suction type hydrometer, then determine the density of the 

engine coolant by referring to the table. 

 
NOTE: The LLC is 50% at all environment in order to prevent 
the corrosion of cooling system parts. 

 

ENGINE COOLING  6B-5 

Diagnosis 

Engine Cooling Trouble 

Condition Possible 

cause Correction 

Engine overheating 

Low Engine Coolant level 

Replenish 

 

Thermo mater unit faulty 

Replace 

 Faulty 

thermostat 

Replace 

 

Faulty Engine Coolant temperature 

sensor 

Repair or replace 

 

Clogged radiator 

Clean or replace 

 

Faulty radiator cap 

Replace 

 

Low engine oil level or use of 

improper engine oil 

Replenish or change oil 

 

Clogged exhaust system 

Clean exhaust system or replace 

faulty parts 

 

Faulty Throttle Position sensor 

Replace throttle valve assembly 

 

Open or shorted Throttle Position 

sensor circuit 

Repair or replace 

 

Damaged cylinder head gasket 

Replace 

 

Loosen V-belt tension 

Adjust belt tension or replace. 

 Collapsed 

hoses 

Replace 

 

Faulty Fan clutch 

Replace 

Engine overcooling 

Faulty thermostat 

Replace 

Engine slow to warm-up 

Faulty thermostat 

Replace 

 

Thermo unit faulty 

Replace 

 

6B-6  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  
level should be between the "MIN" and "MAX" lines of reserve 
tank when the engine is cold. If low, check for leakage and add 
engine coolant 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 engine coolant should also be free 
from oil. 
Replace the engine coolant if excessively dirty. 
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 engine coolant 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 engine coolant using a 

solution that is at least 50 percent antifreeze. 

5.  Fill the radiator to the base of the filler neck. 

 

Fill the engine coolant reserve tank to "MAX" line when the 

engine is cold. 

6.  Block the drive wheels and firmly apply the parking brake

and place the shift lever in the "NEUTRAL" position. 

7.  Remove the radiator cap. Start the engine and warm it up at

2,500 - 3,000 rpm for about 30 minutes. 

8.  When the air comes out from the radiator filler neck and the

engine coolant level has gone down, replenish with the 

engine coolant. Repeat this procedure until the engine 

coolant level does not go down. Then stop the engine and 

install the radiator cap. Let the engine cool down. 

9.  After the engine has cooled, replenish with engine coolant

up to the "MAX" line of the reserve tank. 

10. 

Start the engine. With the engine running at 3,000 rpm,

make sure there is no running water sound from the heater 

core (behind the center console). 

11. If the running water sound is heard, repeat steps 8 to 10. 

 

ENGINE COOLING  6B-7 

Water Pump 

Water Pump and Associated Parts 

 

 
 
 
 
 
 

 

Legend 

1 Water Pump Assembly 

2 O-Ring 
3 Bolt 

 

2 

3 

1

 

 
 
 

 

 

 
 
 
 
 
 
 

 
 
 
 

Removal 

1.  Disconnect battery ground cable. 

2. Drain coolant. 

3.  Disconnect radiator hose (on inlet pipe side). 

4.  Remove timing belt, refer to "Timing Belt" in this manual. 

5.  Remove water pump assembly. 

Inspection 

Make necessary repair and 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: