Parts for your 1993 Nissan Primera-Tx valve

1993 Nissan Primera TX-valve: what it is, where it lives, and how to keep it sweet

Based on the Nissan Primera P10 Factory Service Manual (Heater & Air Conditioner section), the Nissan FAST parts catalogue for P10 models, and common aftermarket catalogues from major air‑conditioning suppliers, the 1993 Nissan Primera runs a thermostatic expansion valve (often called a TX-valve) at the evaporator inlet. So yes, a TX-valve is fitted and very relevant to this model’s air‑con system.

The TX-valve meters refrigerant into the evaporator based on temperature and pressure, keeping the evaporator just on the frosty side of efficient without flooding it. That means colder vents on stinking hot days, steady cabin temps, and better compressor protection. On the 1993 Primera, the valve is mounted on the evaporator inside the HVAC box, typically accessed from the passenger side once the glovebox and related trims are out, and the two A/C pipes at the firewall are disconnected.

When a TX-valve plays up, you’ll often see weak or fluctuating cooling, frosting on one line but not the other, or pressure readings that hunt around. Because this part is smack in the refrigerant circuit, replacement and servicing must be done by a licensed A/C tech. Best practice on a Primera when replacing the TX-valve is to:

• Recover any refrigerant properly, not vented
• Replace the receiver‑drier/accumulator at the same time
• Renew all O‑rings with compatible HNBR items and add the correct compressor oil type and quantity
• Flush lines and the condenser if contamination is suspected (never flush the compressor)
• Pressure‑test with dry nitrogen, evacuate under deep vacuum, then charge by weight

It’s a fiddly job behind the dash, so allow time to avoid cracked plastics and mis‑seated seals. Don’t over‑tighten fittings, use the factory torque specs and a dab of the right refrigerant oil on O‑rings. If the car has been converted from R12 to R134a, a fresh TX-valve calibrated for the refrigerant, new drier, and the right oil are the go. Keep the condenser fins clean and the cabin filter (if fitted) fresh so the TX-valve isn’t fighting airflow issues. With a healthy TX-valve and a tight, clean system, a 1993 Primera’s air‑con will blow cold reliably through Aussie summers and Kiwi nor’westers alike.

Popular questions about the 1993 Nissan Primera TX-valve

Where is the TX-valve located on a 1993 Primera?
It’s mounted on the evaporator inside the HVAC box, usually accessed from the passenger side after removing the glovebox and trim. The two A/C lines pass through the firewall to the valve. Plan on careful disassembly to avoid damaging clips and seals.

Do I need to replace the receiver‑drier when changing the TX-valve?
Yes. Opening the system exposes the drier’s desiccant to moisture, which can lead to acid formation and valve sticking. Replacing the drier, renewing O‑rings, and evacuating the system properly are standard good practice.

Is the TX-valve different for R12 and R134a?
Some valves are cross‑compatible, but calibration can differ. For a converted car, use a valve and oil that suit R134a, replace the drier, and charge by weight to the recommended spec. A licensed A/C technician can confirm the correct parts for the specific Primera variant.