Parts for your 2017 Nissan Serena-Tx valve

2017 Nissan Serena TX Valve: what it does and how to look after it

Based on the Nissan Serena C27 Factory Service Manual (HA: Heating & Air Conditioning) and Nissan FAST parts catalogue entries listing “Valve Assy – Expansion” for both front and rear evaporators, the 2017 Nissan Serena uses a thermostatic expansion valve (TX valve/TXV). Denso system documentation for Nissan applications the same era also specifies TXVs paired with variable-displacement compressors, which matches the Serena’s HVAC layout.

The TX valve meters refrigerant into the evaporator, keeping superheat in check so the Serena’s air-con cools strongly without icing. On C27 models with dual air (front and rear), there’s a TXV at each evaporator. When a TXV sticks or drifts out of spec, owners notice poor cooling at idle, hunting vents, or frost on lines.

TX valves aren’t a regular replacement item, but they should be inspected whenever the system’s opened or cooling performance drops. A workshop will confirm TXV behaviour with gauge readings and a thermometer at the vents. If replacement’s needed, best practice per Nissan service procedures is to recover the refrigerant, replace the valve and all disturbed O-rings, add the correct PAG oil amount, evacuate, then recharge by weight. Always renew the receiver–drier/desiccant (integrated with the condenser on many Serenas) when the circuit’s opened, and swap the cabin filter to keep airflow up.

Front TXV access typically involves removing some dash ducting at the evaporator case, rear TXV access requires trim removal down the left rear quarter. Expect roughly 1.5–3.0 hours for the front and longer for the rear depending on trim level. Use new seals lubricated with the specified oil, observe the torque specs in the HA section, and pressure/leak test before reassembly. Most 2017 Serena markets use R‑134a, always confirm the under‑bonnet label.

Because handling refrigerant is regulated, the job should be done by an ARCtick‑licensed tech in Australia or a certified automotive A/C technician in New Zealand. Good clues a TXV is on the way out include:

• Weak or intermittent cooling, especially at idle or in traffic
• Evaporator or suction line frosting, rapid vent temperature swings
• Abnormal high/low side pressures or metallic debris found in the system

Sort those early and the Serena’s air-con will keep its cool for the long haul.

Popular questions

Where is the TX valve located on a 2017 Nissan Serena?

The front TXV sits at the front evaporator within the HVAC case behind the dashboard, close to the bulkhead where the A/C lines pass through. On dual‑air models, a second TXV is mounted at the rear evaporator assembly behind the left‑side interior trim toward the rear quarter.

What are common signs a Serena TX valve is failing?

Typical signs include poor cooling at idle, vent temperatures that swing hot–cold, frosting on the evaporator lines, and odd gauge readings (very low suction or unstable pressures). If debris is present from a failing compressor, the TXV can plug and restrict flow.

Does the 2017 Serena use R‑134a or R‑1234yf?

Most 2017 Serena C27 vehicles were charged with R‑134a. Always confirm the refrigerant type on the under‑bonnet label and follow the exact charge weight listed there when servicing.