A/C - Description of R-134A System
Classification: HA93-023Section: Air Conditioning
Reference: TECHNICAL BULLETIN NTB93-188
Models: 1994 300ZX
Date: December 21, 1993
1994 300ZX A/C CHANGES FOR R-134a REFRIGERANT
APPLIED MODEL:
1994 300ZX
SERVICE INFORMATION
As part of Nissan's ongoing concern for the environment, the A/C system in the 1994 300ZX is designed for use of R-134a refrigerant. This new refrigerant does not deplete the ozone in the upper atmosphere.
Nissan Technical Bulletin NTB92-001 (HA92-001), entitled "A/C System Changes for R-134a Refrigerant (All Models)" includes general information about R-134a systems. This bulletin describes the specific details of the 1994 300ZX R-134a system. Use this bulletin together with NTB92-001 (HA92-001) for complete information regarding 300ZX R-134a A/C systems.
Important Points
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^ 1994 300ZX A/C system components in contact with R-134a are clearly labeled for R-134a application.
^ The compressor is designed for R-134 a system application only and contains the proper amount of PAG lubricant (p/n KLH00-PAGS1) for the HVAC system. Refer to the Service Manual for specific service procedures.
^ A dual pressure switch is incorporated into the receiver-drier (liquid tank) to provide HVAC system protection. Refer to the Service Manual for a specific technical details and service procedures.
^ The receiver-drier (liquid tank) is a new design incorporating an improved filter, a different desiccant, and increased desiccant amount.
^ Service ports compatible with R-134 a service connectors are incorporated into the design of the hose/pipe assemblies.
Note:
On turbo models only, the battery must be removed to access the low pressure service port.
^ Except for the turbo model, the sight glass has been eliminated from the system as the R- 134a/PAG lubricant mixtures do not exhibit "clear " sight glass characteristics even when properly charged. The sight glass on the turbo model should not be used to check the refrigerant charge.
^ The Suction Throttle Valve (STV) has been eliminated from the Automatic Temperature Control (ATC) HVAC system. The STV component was not used in the Manual Control HVAC system on previous 30OZX vehicles.
^ Evaporator core temperature is regulated by a Thermocontrol Amplifier on both Manual Control and Automatic Temperature Control HVAC systems. This change results in a "cycling clutch" HVAC system.
^ The evaporator has been changed to a "laminate" design allowing for improved heat transfer and system performance.
^ The Thermostatic Expansion Valve (TXV) has been changed to optimize its operating characteristics for the laminate evaporator/R-134a design.
^ The blower fan has been redesigned for improved air flow.
^ The "timer" feature incorporated into the Automatic Temperature Control system logic has been eliminated. This was a running change from 1993 model production.
^ The underhood label has been changed to identify the HVAC system as using R-134a refrigerant and gives the correct charge specification.
Component Identification
The components have been changed for R-134a and are identified as indicated (see illustration).