Parts for your 2012 Subaru Impreza-Tx valve

2012 Subaru Impreza TX‑Valve: what it does, where it lives, and when to replace it

Based on technical documentation, a TX‑valve (thermostatic expansion valve) is fitted to the 2012 Subaru Impreza. The Subaru 2012MY Impreza Service Manual (HVAC section) describes an expansion valve mounted at the evaporator inlet, and the Subaru electronic parts catalogue for GP/GJ chassis lists the A/C “expansion valve” as a serviceable item. DENSO’s passenger vehicle air‑conditioning literature for R‑134a systems in this era also specifies a TX‑valve type metering device rather than a fixed orifice tube. So yes—this model uses a TX‑valve, and it’s relevant to air‑con performance and servicing.

The TX‑valve meters refrigerant into the evaporator, reacting to temperature and pressure so the system cools efficiently without flooding or starving the core. On the 2012 Impreza it’s located at the evaporator assembly behind the glovebox area, clamped to the evaporator tubes. When the valve sticks, blocks with debris, or leaks, the cabin may not get cold, the system can short‑cycle, or frost may build on the pipes.

While the TX‑valve isn’t a routine wear item, it’s smart to assess it whenever the air‑con is diagnosed for poor cooling, after a compressor failure, or any time the system’s been open. A licensed technician should recover the R‑134a, remove the glovebox trim to access the HVAC case, and replace the valve along with new HNBR O‑rings lubricated with the correct PAG oil (Subaru uses ND‑OIL 8/PAG). Evacuate, then recharge to the exact quantity shown on the under‑bonnet label. If the system has been exposed to air or suffered internal contamination, replace the receiver/drier desiccant (integrated with the condenser on many models) and flush lines where appropriate.

• Common symptoms of a faulty TX‑valve: weak cooling at idle, uneven vent temps, line frosting at the firewall, abnormal high/low side pressures, or a constant hiss at the evaporator.
• Good practice during replacement: use new sealing washers/O‑rings, verify sensor bulb seating/clamping if applicable, and check for leaks with nitrogen and an electronic detector before final charge.
• Service tip: always confirm condenser fans and cabin filter condition—restrictions can mimic TX‑valve faults.

Get the TX‑valve right, and the Impreza’s air‑con runs quietly, cycles properly, and keeps cabin temps comfy on scorching Aussie or Kiwi days.

Popular questions

Where is the TX‑valve on a 2012 Subaru Impreza?
It’s mounted on the evaporator unit behind the dash, typically accessed by removing the glovebox and some trim panels. Two refrigerant lines pass through the firewall to this spot, and the valve bolts to the evaporator tubes inside the HVAC case.

Should the TX‑valve be replaced after a compressor failure?
Often, yes. If a compressor sheds debris, the TX‑valve can clog or stick. Many technicians replace the valve and address the desiccant along with a thorough system clean, then evacuate and recharge to the specified amount.

What are the tell‑tale signs of a bad TX‑valve?
Slow or no cool at idle, vent temperature swings, frosting at the evaporator inlet, erratic pressure readings, or a persistent hiss at the dash area. Proper diagnosis with gauges and temperature measurements is recommended before parts are replaced.