Parts for your 2007 Mazda Cx-9-Tx valve

2007 Mazda CX-9 TX Valve: What It Does, Where It Lives, and When to Sort It

Referencing the Mazda Workshop Manual for the 2007 CX‑9 (HVAC section), the Mazda Electronic Parts Catalog, and common OEM service databases (e.g., ALLDATA and Mitchell), this model uses a thermostatic expansion valve (TXV) at the front evaporator. CX‑9s equipped with rear air also run a second TXV at the rear evaporator. So yes—the TX valve is relevant and fitted to the 2007 Mazda CX‑9.

On this Mazda, the TX valve meters refrigerant into the evaporator based on temperature and pressure, keeping the evaporator cold without flooding it. That control helps deliver steady cabin temps, better demisting, and protects the compressor from liquid slugging. In short, it’s a small part doing a big job in the air‑con system.

For servicing, the TXV isn’t a routine replacement item, but it’s worth attention when chasing air‑con issues or any time the system’s opened. Typical clues a TX valve is crook include weak cooling at idle, frosting on the evaporator or lines, erratic vent temps, or odd high/low gauge readings that don’t respond to a correct charge. Contamination from a failing compressor can also jam a valve.

• Location: The front TXV is a block‑type unit at the firewall bulkhead where the A/C lines pass to the evaporator. Rear A/C models have another TXV at the rear evaporator assembly.
• Best practice on replacement: Always use new O‑rings, add the correct PAG oil balance for parts replaced, evacuate the system properly, and recharge by weight to spec.
• Replace the receiver‑drier/desiccant whenever the system is opened or a TXV is replaced to keep moisture out.
• If the system’s contaminated, flush appropriate lines and the condenser if serviceable, don’t flush the TXV or compressor—replace as required.

Because refrigerant handling is regulated, A/C work should be carried out by a licensed technician (ARCtick licence in Australia or the appropriate NZ refrigerant handling certification). They’ll confirm correct operation with pressure/temperature checks and scan for HVAC fault codes if the vehicle’s equipped.

Look after the basics—clean cabin filter, condenser fins free of debris, and periodic system checks—and the TX valve will typically run for years without drama.

Does the 2007 Mazda CX‑9 definitely have a TX valve?

Yes. The Mazda Workshop Manual and Mazda EPC specify a TXV at the front evaporator, models with rear air have a second TXV at the rear unit. It’s the metering device used on this platform rather than a fixed orifice tube.

Where is the TX valve located on a 2007 CX‑9?

The front TXV is mounted at the firewall where the A/C lines enter the heater/evaporator case. On vehicles with rear A/C, the rear TXV sits at the rear evaporator assembly, accessed from the rear quarter interior trim area.

When should the TX valve be replaced on a 2007 CX‑9?

It’s replaced if diagnosed faulty (poor cooling, frosting, unstable pressures) or whenever the evaporator is changed. If the system has been contaminated by compressor debris, replacing the TXV and the receiver‑drier/desiccant is wise, along with proper flushing and a recharge by weight.