Parts for your 2010 Audi Q5-Tx valve

2010 Audi Q5 TX Valve (Thermostatic Expansion Valve)

Based on Audi technical sources (ElsaWin/erWin workshop information and the ETKA parts catalogue for the 8R Q5 platform), the 2010 Audi Q5 uses a thermostatic expansion valve (TXV) mounted at the evaporator connection on the bulkhead. Audi parts listings show an A/C expansion valve for this model (commonly referenced under part families like 8K0 820 679 and supersessions), confirming a TX valve is fitted and relevant to the 2010 Q5’s R134a air-con system.

The TX valve’s job is to meter refrigerant into the evaporator according to load and temperature, keeping evaporator “superheat” in the sweet spot. That way, the cabin gets consistently cold air without the evaporator freezing, efficiency stays high in stop–start traffic, and compressor stress is kept in check. On the Q5, the TXV works hand-in-glove with the variable-displacement compressor to balance low vent temps with smooth, quiet operation.

When a TX valve sticks, blocks, or mis-meters, drivers may notice weak cooling, vent temperatures that swing hot–cold, frost on the suction line, hissing at the firewall, or odd pressure readings on the gauges. Because the Q5 also uses a compressor control valve, good diagnosis matters—what looks like a compressor fault can sometimes be a TXV issue, and vice versa.

The TX valve isn’t a routine service item, but it should be replaced if it’s faulty, contaminated after a compressor failure, or corroded/leaking. Best practice on this Audi includes evacuating the system properly, replacing the receiver–drier/desiccant element (commonly integrated in the condenser on VAG models), fitting new green HNBR O-rings, and recharging to the exact R134a mass shown on the under‑bonnet label. A nitrogen/trace-gas leak test and a solid vacuum hold are must-do steps.

• Access: located at the evaporator connections on the bulkhead, expect to remove engine-bay trims and A/C lines at the firewall.
• Install tips: torque fasteners to spec, lightly oil new O-rings with the correct PAG oil, and account for any oil balancing when components are replaced.
• Post-service: clear HVAC fault codes, verify both radiator fans run, and confirm stable vent temps on a road test.

For long-term reliability, keep the condenser clean, replace the cabin filter on schedule, and have the air-con checked if cooling drops off—sorting a marginal TXV early can save the compressor from overwork across our hotter Aussie and Kiwi summers.

Does the 2010 Audi Q5 use a TX valve or an orifice tube?

This model uses a thermostatic expansion valve (TXV) at the evaporator, not an orifice tube. Audi’s factory parts and service information list a dedicated A/C expansion valve for the 2010 Q5 (8R).

Where is the TX valve on a 2010 Q5, and how long does replacement take?

It’s mounted at the evaporator connections on the bulkhead (firewall). Typical workshop time ranges from about 1.0 to 2.0 hours plus evacuate/recharge, depending on access and corrosion. Always include new O‑rings and replace the drier element.

What symptoms point to a failing TX valve on this Audi?

Common signs include poor cooling at idle or cruise, vent temps that fluctuate, icing on the suction line, and abnormal high/low-side pressures. Proper diagnosis is key because compressor control valve issues can mimic TXV faults.