Parts for your 2018 Mazda Cx-5-Tx valve

2018 Mazda CX-5 TX Valve (A/C Expansion Valve)

Yes, the 2018 Mazda CX-5 is fitted with a TX valve (thermal expansion valve), also called an A/C expansion valve. This isn’t guesswork: the Mazda Workshop Manual for the CX-5 (KF) HVAC section identifies an “A/C Expansion Valve” at the evaporator, the Mazda Electronic Parts Catalogue lists an expansion valve assembly for 2017–2019 CX-5 models, and common aftermarket parts catalogues list direct-fit TX valves for this vehicle. Those technical sources confirm the CX-5 uses a TXV-based system rather than an orifice-tube/accumulator setup.

On this Mazda, the TX valve meters refrigerant into the evaporator based on temperature and pressure, keeping the evaporator at the sweet spot for cooling without icing. By controlling superheat, the valve helps stabilise vent temps, improves demist performance, and protects the compressor from liquid slugging.

There’s no routine service interval for the TX valve, but it’s smart to inspect when the system is open, say during a condenser or compressor replacement. If the A/C is slow to cool, swings hot–cold, hisses excessively, shows frost at the firewall joint, or your pressure readings look off (very high high-side with starved low-side, or vice versa), the TXV may be sticking or contaminated.

• Typical reasons to replace: contamination after compressor failure, internal sticking from debris/moisture, or incorrect superheat control causing poor cooling.
• Best practice when replacing: renew the O-rings, add the specified PAG oil quantity for the component, and replace the receiver/drier (desiccant) in the condenser to protect the new valve.
• Location: mounted at the evaporator connections on the bulkhead (firewall), typically serviceable from the engine bay on the CX-5 (KF).

Replacement is a licensed task in Australia and New Zealand. A technician will recover the refrigerant, remove the valve and lines at the bulkhead, install a new TXV with fresh O-rings lubricated with the correct oil, evacuate the system, and recharge with the refrigerant and weight shown on the under-bonnet label. It’s wise to fit a new desiccant bag in the condenser and use a calibrated scale and vacuum pump to avoid repeat issues. If a compressor has failed, request a system flush (lines only—never the TXV or compressor), new drier, and a clean cabin filter to keep airflow up.

Day-to-day, owners can keep the A/C healthy by running it regularly, keeping the condenser free of road grime and bugs, and replacing the cabin filter on schedule. The TX valve itself only needs attention when symptoms point to a metering fault or the system’s been opened.

Popular questions

Does the 2018 Mazda CX-5 have a TX valve or an orifice tube?
It uses a TX valve at the evaporator. Mazda’s workshop documentation and parts catalogue both list an “A/C Expansion Valve” for the CX-5 (KF), and major aftermarket suppliers sell a direct-fit TXV for this model. There’s no fixed orifice tube in this setup.

Where is the TX valve on a 2018 CX-5?
It’s fitted at the evaporator connection on the bulkhead (firewall). Technicians usually access it from the engine bay, removing the refrigerant lines at the firewall joint and unbolting the block-style valve.

Should the drier be replaced when changing the TX valve?
Yes, strongly recommended. The receiver/drier (desiccant) is integrated with the condenser on the CX-5. Replacing it helps trap moisture and debris so the new TX valve doesn’t stick, especially after a compressor failure or any major A/C repair.