Parts for your 2013 Audi Q5-Tx valve

2013 Audi Q5 TX-valve: what it does and when to replace it

Technical sources confirm the 2013 Audi Q5 (8R) uses a thermostatic expansion valve (TX-valve) in its air-conditioning system. This is documented in Audi’s Heating/Ventilation/Air Conditioning Repair Manual (Rep. Gr. 87) on erWin/ELSA, which includes procedures titled “Expansion Valve – Remove and Install”. Audi Self-Study Programme content for the Q5 platform likewise depicts a receiver-drier and an expansion valve at the evaporator inlet. The Audi ETKA parts catalogue for the 8R Q5 (MY2013) lists an “Expansion valve” (e.g., 8K0 820 679 variants) fitted to the A/C evaporator assembly.

On the 2013 Audi Q5, the TX-valve meters refrigerant into the evaporator, reacting to evaporator outlet temperature and pressure so the system cools efficiently without icing up. Paired with the Q5’s variable-displacement compressor, the TX-valve keeps cabin temps steady across Aussie and Kiwi climates, whether it’s a frosty morning in Dunedin or a scorching Perth arvo.

When a TX-valve sticks or clogs (often from moisture or compressor swarf), owners may notice weak cooling at idle, wildly fluctuating vent temps, frosting on the low-side line, hissing at the dash, or pressure readings that don’t stack up. It’s common to confuse a lazy compressor control valve (N280) with a dodgy TX-valve, so proper diagnosis with gauges and temperature probes is key.

Replacement is a workshop job requiring refrigerant recovery. The valve sits at the evaporator on the HVAC case, access typically involves trim/glovebox removal on the passenger side. Best practice during replacement includes new O-rings, a deep vacuum and leak check, charging the exact refrigerant weight shown on the under-bonnet label, and adding the correct PAG oil amount. If there’s contamination, flush the lines and consider the condenser’s desiccant. In Australia and New Zealand, A/C work must be performed by a licensed technician (ARCtick in AU).

There’s not much “maintenance” for a healthy TX-valve, but a clean cabin filter, running the air-con regularly, and timely leak repairs help it live a long life. During major A/C service—especially after compressor failure—replacing the TX-valve is cheap insurance against repeat issues. Expect 1.5–3.0 hours labour depending on access, with results that bring the Q5’s climate control back to crisp, consistent performance.

• Typical signs of trouble: erratic cooling, icing lines, noisy hissing, or abnormal gauge readings.
• Always replace O-rings, evacuate thoroughly, and charge by weight to factory spec.
• Consider TX-valve renewal whenever the compressor or contaminated components are replaced.

Popular questions

Where is the TX-valve on a 2013 Audi Q5?
The TX-valve is mounted at the evaporator inlet on the HVAC case, generally accessed from the passenger side. Reaching it usually means removing trim and the glovebox rather than pulling the whole dash. A licensed A/C technician can confirm access path for your engine variant.

What symptoms point to a failing TX-valve on a Q5?
Common clues include poor cooling at idle, rapidly changing vent temperatures, frost or heavy sweating on the low-pressure line, and odd hissing behind the dash. Gauge checks may show high low-side pressure or starving/flooding behaviour. Always rule out the compressor control valve and low refrigerant charge first.

Should the TX-valve be replaced with the compressor?
It’s strongly recommended if the old compressor failed internally or there’s evidence of debris. Along with new O-rings and a system flush, a fresh TX-valve helps protect the new compressor and restores correct metering, reducing the risk of callbacks and uneven cooling.