Parts for your 2016 Audi Q5-Tx valve

2016 Audi Q5 TX-valve: what it does, why it matters, and how to look after it

Based on technical sources including Audi’s factory repair information (erWin/ELSA for the 8R Q5 air conditioning system) and the Audi ETKA parts catalogue for the 2016 Q5, this model is built with a thermostatic expansion valve (TX-valve) at the evaporator block. Aftermarket catalogues for A/C components covering 2009–2017 Q5 models also list a direct-fit expansion valve, confirming that a TX-valve is indeed used and relevant on the 2016 Audi Q5.

On a 2016 Audi Q5, the TX-valve meters liquid refrigerant into the evaporator, keeping superheat in the sweet spot so the system cools quickly without slugging the compressor. Paired with the Q5’s variable-displacement compressor, the TX-valve helps deliver stable cabin temps, better fuel economy, and less cycling in Aussie and Kiwi conditions.

There’s no routine “maintenance” for a TX-valve, but it should be assessed any time the A/C is underperforming. Telltales of a crook or sticking valve include weak cooling at idle but decent on the motorway, frost on the evaporator outlet, a noticeable hiss at the bulkhead, or pressure readings that don’t line up with ambient conditions. Contamination, moisture, or incorrect oil can all make a TX-valve misbehave.

When servicing or replacing the TX-valve on a 2016 Q5, an ARCtick-licensed tech should:

• Recover refrigerant, replace all disturbed O-rings, and lubricate with the correct PAG oil for the Q5’s compressor.
• Leak-test with dry nitrogen, then evacuate for an adequate period to remove moisture.
• Recharge by weight to the spec on the under-bonnet label (R134a for this model year), and verify superheat/subcool figures.
• Replace the receiver–drier/desiccant (integrated in the condenser on this platform) if the circuit has been opened or the system’s been contaminated.
• Flush only serviceable lines if contamination is light, if the compressor has let go or the condenser is microchannel and clogged, replacement is the safer bet.

Access to the Q5’s TX-valve is at the evaporator connections on the bulkhead where the two A/C lines enter the cabin. After fitting, it’s wise to run an HVAC basic setting/adaptation with a scan tool to ensure blend and temperature doors are behaving, then road-test with the A/C performance checked against ambient.

Look after the basics—clean condenser face, correct cabin filter, proper refrigerant charge—and the TX-valve will usually keep doing its job for years without fuss.

Popular questions about 2016 Audi Q5 TX-valve

Where is the TX-valve located on a 2016 Audi Q5?
It’s mounted at the evaporator block on the bulkhead (firewall), where the two A/C lines pass into the cabin. On the Q5 8R, access is typically from the engine bay after removing covers and components around the plenum area. A pro will confirm access steps based on engine and RHD/LHD layout.

Do I need to replace the drier when changing the TX-valve?
Yes, best practice is to renew the receiver–drier/desiccant any time the circuit is opened. On the 2016 Q5 it’s integrated into the condenser. Replacing it, along with all disturbed O-rings and a proper vacuum/charge, helps prevent moisture and acid formation that can damage the new valve.

What usually causes a TX-valve to fail on a Q5?
Contamination (metal debris, sludge), moisture, or incorrect oil are the common culprits. Valves can stick, overfeed, or underfeed as a result. Also note that a faulty evaporator temperature sensor or blend door issue can mimic TX-valve problems, so proper diagnosis with gauges and a scan tool is important.