Parts for your 2020 Audi Q5-Tx valve

2020 Audi Q5 TX valve — fitment, purpose, and service advice

Based on OEM technical literature and parts catalogues, the 2020 Audi Q5 (FY platform) uses a block-style thermal expansion valve (TX valve) at the evaporator. Audi’s workshop manuals for the FY Q5 HVAC system list an expansion valve at the evaporator housing, and Audi ETKA parts catalogue groups for Heating/Air Conditioning show an expansion valve for FY-series Q5 models from 2018 onwards. Major A/C component catalogues from OE suppliers (DENSO, MAHLE/Behr, Valeo) also list a TXV for 2018–2021 Q5 with R‑1234yf refrigerant. Those sources collectively confirm the TX valve is fitted rather than a fixed orifice tube.

On the 2020 Q5, the TX valve meters refrigerant flow into the evaporator, reacting to temperature and pressure to keep the evaporator just cold enough to pull heat and humidity out of the cabin without freezing. In day-to-day terms, it’s the little metering brain that helps the air-con stay consistently chilly in Aussie and Kiwi conditions, whether the car’s idling in traffic or cruising down the motorway.

While the TX valve itself isn’t a routine replacement item, it sits at the heart of A/C performance. If it sticks open or closed, owners might cop symptoms like warm air at idle, vent temps that swing hot–cold, frosting on the low-side line, or pressure readings that don’t stack up during diagnosis. Because the 2020 Q5 runs R‑1234yf, correct charge weight is critical, a slightly off charge can make a healthy TX valve look crook.

Good servicing practice for a Q5 TX valve includes:

• Recovering and weighing the refrigerant, then recharging to the exact R‑1234yf spec after any A/C work.
• Replacing receiver–drier elements when the system is opened, and fitting new O‑rings lubricated with the right PAG oil.
• Inspecting for debris or desiccant contamination, if found, flushing lines and considering compressor/condensor checks.
• Ensuring condenser and radiator faces are clean and that cooling fans operate properly, so the TX valve isn’t forced to compensate for poor heat rejection.

Replacement typically means accessing the valve at the firewall/evaporator area, removing line clamps, swapping the block valve, and torquing fasteners to spec. It’s a tidy job for an A/C technician with the right recovery gear, they’ll also leak-test with nitrogen and vacuum-check before recharging. When buying parts, sticking with OE or quality OE‑equivalent valves pays dividends in stable superheat control and quieter operation. With those boxes ticked, the Q5’s air-con will stay crisp, efficient, and drama-free for heaps of kilometres.

Popular questions about the 2020 Audi Q5 TX valve

Does the 2020 Audi Q5 use a TX valve or an orifice tube?

The FY‑series Q5 uses a thermal expansion valve mounted at the evaporator. This is confirmed by Audi’s HVAC workshop procedures and ETKA parts listings, plus OE supplier catalogues that specify a TXV for R‑1234yf systems on 2018–2021 Q5 models.

What are common signs the TX valve needs attention on a 2020 Q5?

Tell-tales include weak cooling at idle, erratic vent temps, frost on the low-side line near the firewall, unusual hissing, or pressure readings that show starving or flooding of the evaporator. Always rule out incorrect refrigerant charge, blocked condenser fins, or a failing compressor control valve first.

Should the TX valve be replaced as routine maintenance?

No. It’s not a scheduled replacement item. It’s replaced when faulty or when the A/C system has been contaminated. Any time the system is opened, new O‑rings and a receiver–drier element are smart practice, followed by a precise R‑1234yf recharge.