Parts for your 2018 Subaru Forester-Tx valve

2018 Subaru Forester TX Valve: Purpose, Service and Replacement

Yes, the 2018 Subaru Forester uses a TX valve (thermal expansion valve). Subaru’s factory service manual for the SJ Forester (2014–2018) identifies an expansion valve at the evaporator inlet in the HVAC assembly, and genuine parts catalogues list the OEM expansion valve for these models (commonly referenced as Subaru part number 73520SG000, market-dependent). That makes a TX valve directly relevant to A/C performance on a 2018 Forester.

The TX valve’s job is to precisely meter liquid refrigerant into the evaporator, keeping the outlet slightly superheated so the compressor doesn’t cop liquid slugging. By matching flow to heat load, it helps deliver steady, frosty vent temps in traffic and on the open road. Compared with a fixed orifice setup, a TXV system responds better to changing Aussie and Kiwi weather and varying engine speeds, which is why Subaru engineered it into the SJ Forester platform.

It’s not a scheduled service item, but a crook TX valve can spoil the A/C’s day. Telltale signs include weak cooling (especially at idle), air that goes cold then warm, frost on the evaporator or suction line, and pressure readings that are too high or too low. A noisy or recently failed compressor, contamination, or moisture in the system can also stick or block the valve.

On the 2018 Forester, the TX valve is mounted at the evaporator on the cabin side of the firewall, typically accessed via the glovebox area. Replacement and any A/C opening should be handled by an ARCtick-licensed technician. Best practice when the system is opened: replace the valve if it’s suspect, renew all O-rings, evacuate properly, and recharge by weight. If there’s been a compressor failure or the system’s been open to atmosphere, replace the receiver–drier/desiccant (integrated with the condenser on many SJ models) and consider a flush to clear debris. Use the correct PAG oil type/quantity as per the Subaru manual, pressure-test with nitrogen, and leak-check before re-gassing.

Routine care helps: keep the condenser clean, change the cabin filter on time, and run the A/C regularly to circulate oil. If cooling performance drops off, get proper gauge diagnostics done rather than just a re-gas—finding the root cause protects the compressor and keeps the Forester cool all summer.

Does the 2018 Subaru Forester have a TX valve or an orifice tube?

It has a TX valve at the evaporator. Subaru’s SJ Forester service documentation specifies an expansion valve, and genuine Subaru parts listings for 2014–2018 Forester include the expansion valve (commonly referenced as 73520SG000). No fixed orifice tube is used on this model.

What are common symptoms of a failing TX valve on a 2018 Forester?

Expect poor or inconsistent cooling, evaporator or suction-line icing, and odd pressure readings. You may notice cold air at speed but warm air at idle, or temps that swing hot–cold. Contamination after a compressor issue can also jam the valve.

Should the TX valve be replaced when changing the compressor?

Often, yes. If the compressor failed or the system is contaminated, replacing the TX valve and renewing the receiver–drier/desiccant is smart insurance. It helps prevent repeat failures and ensures correct refrigerant control with the new compressor.