Parts for your 2014 Audi Q5-Tx valve

2014 Audi Q5 TX-valve: fitment, purpose, and service tips

Based on factory sources, the 2014 Audi Q5 (type 8R) does use a thermostatic expansion valve (TX-valve, often an H-block). Audi’s ETKA parts catalogue lists an A/C expansion valve for the 8R Q5 under the HVAC group (e.g., p/n series 8K1 820 679 and supersessions), and the Audi ElsaWin workshop manual details removal/installation at the evaporator connections on the bulkhead. So the TX-valve is relevant and fitted to this model.

On the 2014 Audi Q5, the TX-valve meters liquid refrigerant into the evaporator to match heat load, maintaining the right superheat so the evaporator stays cold without flooding. That precise control is a big reason the Q5’s air-con can stay crisp on a scorching day and steady when cruising the motorway. It also plays nicely with the variable-displacement compressor most Q5s run, helping keep pressures stable and efficiency up.

When a TX-valve starts to play up, drivers might notice weak cooling at idle or at highway speeds, frosty or sweating lines at the firewall, intermittent cold air, hissing, or pressure readings that don’t make sense. A stuck-closed valve can starve the evaporator, stuck-open can overfeed it and risk icing. Because faults can mimic a crook compressor or a blocked drier, proper diagnosis with manifold gauges and temperature checks is key.

Replacement on a Q5 typically happens at the engine-side bulkhead where the aluminium lines enter the HVAC box. It’s a straightforward job for a licensed A/C tech but does require system recovery, new O-rings, correct torque on the H-block bolts, deep vacuum, leak testing, and an accurate regas. Use the factory-specified refrigerant (most 2014 AU/NZ Q5s are R134a) and the correct PAG oil type/quantity noted on the under-bonnet label or in Audi service data.

Good practice when the system’s opened is to replace the receiver/drier (desiccant) to keep moisture at bay. Flushing is only advised if there’s evidence of contamination (e.g., compressor failure). Keep the interior cabin filter fresh so airflow over the evaporator stays healthy, and run the air-con regularly to circulate oil and keep seals happy.

If the valve’s being renewed because of metal debris or black death, expect a more thorough clean and potentially a new compressor and condenser. Otherwise, a preventative TX-valve and drier replacement during major A/C service can be cheap insurance for a Q5 that does big kilometres or to sort nagging, inconsistent cooling.

• Common signs: weak cooling, evaporator icing, odd hissing, high/low side pressures out of spec.
• Service tips: always replace O-rings, add the right oil amount, vacuum to below 500 microns, and verify superheat/subcooling after regas.

FAQs

Where is the TX-valve on a 2014 Audi Q5?
It’s mounted at the bulkhead where the A/C lines pass into the cabin, bolted to the evaporator inlet/outlet. On most Q5s it’s accessible from the engine bay once the lines and insulation are removed, so the dash doesn’t usually need to come out.

How can someone tell if the TX-valve or the compressor is the issue?
A TX-valve fault often shows as uneven line temps at the firewall, evaporator icing, and pressures that don’t track with engine speed. A failing compressor tends to give low capacity across the board, metal debris in the system, and abnormal compressor noises. Proper diagnosis with gauges and temperature probes is best.

Does the 2014 Audi Q5 use an orifice tube or a TX-valve?
This model uses a thermostatic expansion valve (TXV/H-block), not a fixed orifice tube. The TXV suits the Q5’s system by actively regulating flow for stable cooling and efficiency.