Isuzu KB P190. Manual - part 18

1-38  HEATER AND AIR CONDITIONING 

8)  Charge the system to the specified amount and then close 

the low-pressure hand valve. 

 Refrigerant 

Amount 

g(lbs)

4JA1-T, 4JH1-TC, C24SE 

720 (1.59) 

4JJ1-TC (Standard Output) 

4JJ1-TC (High Output) 

4JK1-TC (High Output) 

 

650 (1.43) 

 

9) Check for refrigerant leaks by using a HFC-134a leak 

detector. 
•  A fully charged system is indicated by the sight glass on 

the receiver/drier being free of any bubbles (Refer to 

"Reading Sight Glass"). 

•  Check the high and low pressure value of the manifold 

gauge. (Refer to “CHECKING REFRIGERANT SYSTEM 

WITH MAINFOLD GAUGE” in SERVICE 

INFORMATION.) 

Immediately after charging refrigerant, both high and low 
pressures are slightly high and to the left of the gauge, but they 
settle down to the guide pressure valves as shown below: 

•  Ambient temperature; 30∼35°C (86∼95°F) 
• Guide 

pressure 

 High-pressure 

side; 

 Approx. 

1373

∼1670 kPa (14∼17 kg/cm

2 

/ 199

∼242 psi) 

 Low-pressure 

side; 

 Approx. 

127

∼245 kPa (1.3∼2.5 kg/cm

2 

/ 18

∼36 psi) 

10) Close the low pressure hand valve and charge valve of the

refrigerant container. 

11) Stop the air conditioning and the engine. 

12) Disconnect the high and low pressure hoses from the 

manifold gauge fittings. 

 

 

 
 

HEATER AND AIR CONDITIONING  1-39 

Reading Sight Glass 

 

High and low 
pressure pipe 
temperature 

The high pressure 
pipe is hot and the 
low pressure pipe 
is cold.  There is a 
distinct difference 
in temperature 
between them. 

The high pressure 
pipe is warm and 
the low pressure 
pipe is cool.  There 
is no great 
difference in 
temperature 
between them. 

There is little 
difference in 
temperature 
between the high 
pressure pipe and 
the low pressure 
pipe. 

The high pressure 
pipe is hot and the 
low pressure pipe 
is slightly warm. 
There is a 
difference in 
temperature 
between them. 

Sight glass 
condition 

Almost transparent. 
A flow of bubbles 
can be seen, but 
they disappear 
when the throttle is 
opened. 

 

 

A flow of bubbles 
always can be 
seen.  It appears 
sometimes 
transparent, and 
sometimes frothy. 

 

Something like fog 
faintly can be seen. 

 

Even at idle with 
the fan at "HI" (with 
the window fully 
open), the bubbles 
cannot be seen. 

 

 

 

 

 

 

Air conditioning 
cycle condition 

 

OK 

NG 

(Not enough 

refrigerant) 

NG 

(Almost no 

refrigerant) 

NG 

(Too much 

refrigerant) 

 

The sight glass provides accurate diagnosis only under the following conditions. 

If the vehicle can be tested under these conditions, check the sight glass appearance and compare to the chart. 

*  Engine speed Idling 

*  A/C switch "ON" 

*  Blower fan operating at highest speed 

*  Air source selector lever at "RECIRC" 

*  Temperature control knob at coldest position 

*  Ambient temperature below 35

°C (95°F) and humidity below 70% (See NOTE 1) 

*  High side pressure less than 1470 kPa (15 kg/cm

2 

/ 213 psi) (See NOTE 2) 

 
NOTE 1 
If the vehicle cannot be moved to a testing location that meets these specifications, then the sight glass cannot be 

used for diagnosis.  You must discharge and recover the refrigerant, then recharge the system with the specified 

amount of refrigerant.  Then continue checking the system performance. 

 
NOTE 2 
If the high side pressure is greater than stated, the sight glass cannot be used for diagnosis.  You must discharge 

and recover the refrigerant, then recharge the system with the specified amount of refrigerant.  Then continue 

checking system performance. 
 
 

1-40  HEATER AND AIR CONDITIONING 

CONDENSER 

 

 REMOVAL AND INSTALLATION (4JH1-TC, 4JJ1-TC Standard Output) 

 

13

12

8

10

11

14

10

9

6

7

5

2

3

1

4

14

10

4JH1-TC

4JJ1-TC

Standard Output

(RHD)

14

10

4JJ1-TC

Standard Output

(LHD)

9

 

 

This illustration is based on RHD model 

 

RTW710LF001401 

Removal Steps   

 

1. Radiator grille 

 

2. Front bumper fascia 

•  Refer to SECTION 2A “FRONT 

BUMPER” 

 

3. Front bumper impact support assembly 

• Refer to SECTION 2A “FRONT 

BUMPER” 

 

4. Air cleaner assembly 

 

5. Inter cooler 

•  Refer to SECTION 6A “INTER COOLER”

 

6. Engine hood lock  

 

7. Engine hood front end stay 

 

8. Pressure switch connector 

 

9. Condenser fan connector 

  10. Refrigerant line 
  11. Refrigerant line 
  12. Receiver/drier bracket 
 13. 

Receiver/drier 

  14. Condenser assembly 

 

Installation Steps 

  14. Condenser assembly 
 13. 

Receiver/drier 

  12. Receiver/drier bracket 
  11. Refrigerant line 
  10. Refrigerant line  
 

9. Condenser fan connector 

 

8. Pressure switch connector 

 

7. Engine hood front end stay 

 

6. Engine hood lock 

 

5. Inter cooler 

•  Refer to SECTION 6A “INTER COOLER”

 

4. Air cleaner assembly 

 

3. Front bumper impact support assembly 

•  Refer to SECTION 2A “FRONT 

BUMPER” 

 

2. Front bumper fascia 

•  Refer to SECTION 2A “FRONT 

BUMPER” 

 

1. Radiator grille 

 

HEATER AND AIR CONDITIONING  1-41 

 

 

 REMOVAL AND INSTALLATION (4JJ1-TC High Output, 4JK1-TC High Output, 4JA1-T) 

 

 

 

 

 

This illustration is based on RHD model 

 

RTW710LF001501 

 

Removal Steps   

 

1. Radiator grille 

 

2. Engine hood lock 

 

3. Engine hood front end stay 

 

4. Pressure switch connector 

 

5. Condenser fan connector 

 

6. Refrigerant line 

 

7. Refrigerant line 

 

8. Receiver/drier bracket 

 9. 

Receiver/drier 

  10. Condenser assembly 

 

 

Installation Steps 

  10. Condenser assembly 

 9. 

Receiver/drier 

 

8. Receiver/drier bracket 

 

7. Refrigerant line 

 

6. Refrigerant line 

 

5. Condenser fan connector 

 

4. Pressure switch connector 

 

3. Engine hood front end stay 

 

2. Engine hood lock 

 

1. Radiator grille