Insufficient Cooling; No Cooling; Intermittent Cooling - Mazda MX-5 1990 Workshop Manual

u
Item
1
2
3
4
U-12
TROUBLESHOOTING GUIDE
Symptom: Insufficient cooling.
SIGHT GLASS
05UOUX-020
Symptom
Bubbles present in sight glass
No bubbles present in sight glass
Immediately after air conditioner turned off,
refrigerant in sight glass stays clear
When air conditioner turned OFF, refrigerant
foams, and then sight glass becomes clear
05UOUX-021
No cooling.
Intermittent cooling.
Step 1 Checking refrigerant charge
1. Run the engine at a fast idle.
2. Operate the air conditioner at maximum cooling for a few
minutes.
3. Observe the sight glass to determine the amount of refriger-
ant and the related action as shown below.
Amount of refrigerant Action
I nsufficient refrigerant Check refrigerant pressure,
go to Step 2
Too much or proper amount of Turn air conditioner OFF, and
refrigerant watch bubbles (Refer to Items 3
and 4)
Too much refrigerant Check refrigerant pressure,
go to Step 2
Proper amount of refrigerant
Refrigerant amount normal
9MUOUX-073
Step 2 Checking refrigerant pressure
1 . Connect the AIC manifold gauge set.
2. Operate the engine at 2,000 rpm and set the air condition-
er to maximum cooling.
3. Measure the refrigerant pressure.
Normal pressure
Low-pressure side:
147-294 kPa (1.5-3.0 kg/cm
2
,
21-43
PSi~
High-pressure side:
1,177-1,619 kPa (12.0-16.5 kg/cm
2
,
171-235 psi)
4. If the pressures are not as specified, refer to the chart on
the next page and check the system.
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