Parts for your 2004 Subaru Forester-Tx valve

2004 Subaru Forester TX valve: purpose, servicing and replacement

Yes, the 2004 Subaru Forester uses a thermostatic expansion valve (TX valve). This is confirmed by the Subaru Forester (SG, 2003–2008) Factory Service Manual HVAC section, which shows a TX valve mounted at the evaporator inlet, by genuine parts catalogues listing an A/C expansion valve (commonly referenced as 73520SA000) for 2003–2005 Forester, and by major service databases and aftermarket catalogues (e.g., DENSO, Mitchell1/ALLDATA) that specify a TX valve rather than an orifice tube for this model.

On this Forester, the TX valve meters refrigerant into the evaporator based on outlet temperature and pressure, helping the air-con hold steady vent temps without overfeeding liquid. By regulating superheat, it protects the compressor from slugging and keeps performance crisp in stop–start traffic and on hot Aussie or Kiwi summer days. It’s a compact, block-style valve bolted to the evaporator pipes, accessed from behind the glovebox area where the evaporator case lives.

Signs the TX valve is on the way out include weak cooling at idle but OK on the open road, evaporator or suction line icing, hissing that comes and goes, or pressure readings that are erratic (high high-side and low low-side, or the reverse). Contamination from a failing compressor can also jam the valve, so if there’s black death or debris in the system, the TX valve is often collateral damage.

Good servicing practice on a 2004 Forester when addressing the TX valve typically looks like:

• Recovering the R134a, replacing the TX valve and O-rings, and renewing the receiver–drier/desiccant when the system’s opened.
• Checking and cleaning the evaporator case and ensuring the cabin filter isn’t choked.
• Evacuating, then recharging to the correct R134a spec and verifying superheat/subcool with stable pressures.

1. Confirm fault with proper diagnostics (temperature drop, pressure readings, scan data for A/C request and fans).
2. Access the evaporator housing via the glovebox area, unbolt the block-style TX valve from the lines.
3. Fit new valve and quality O-rings lubricated with the correct PAG oil, observe factory torque specs.
4. Replace the receiver–drier/desiccant, evacuate thoroughly, recharge to spec, then leak-test and performance-test.

Because handling refrigerant requires the right equipment and certification, use an ARCtick-licensed technician in Australia or a technician compliant with New Zealand refrigerant handling regulations. Done properly, a fresh TX valve restores consistent cooling, protects the compressor, and keeps the Forester’s air-con performing as it should.

• Where is the TX valve on a 2004 Subaru Forester?
  The TX valve sits at the evaporator inlet, behind the glovebox area. It’s a block-style valve bolted to the pipe connections going into the evaporator case, close to the firewall.
• Do I have to replace the receiver–drier when changing the TX valve?
  Yes, it’s strongly recommended whenever the system is opened. The drier captures moisture and debris, leaving an old one in can shorten the life of the new valve and compromise cooling.
• What refrigerant does this model use?
  The 2004 Forester was factory-filled with R134a. Stick with the specified charge amount and correct PAG oil type/volume for reliable performance and compressor longevity.