Parts for your 2019 Audi Q5-Tx valve

2019 Audi Q5 TX Valve — What It Does and When To Service It

Drawing on Audi ElsaPro/erWin workshop information for the FY-series Q5 climate control system, Audi Self-Study material covering R1234yf air-con architecture, and compressor application guides from OEM suppliers used by Audi, the 2019 Audi Q5 is fitted with a thermostatic expansion valve (TXV). So yes, a TX valve is relevant and used on this model.

On the 2019 Audi Q5, the TX valve meters refrigerant into the evaporator based on temperature at the outlet, keeping superheat in the sweet spot. That means stable vent temps, quick cool-down on a hot arvo, and solid performance at idle without the compressor cycling its head off. Because the Q5 runs a variable-displacement compressor and R1234yf, a TXV is the designed match-up, delivering smooth control across different loads and Kiwi/Aussie climates.

The TXV sits at the evaporator inlet on the HVAC housing (at the bulkhead), where the two A/C lines meet the cabin unit. It’s not a periodic service item, but it does rely on a clean, moisture-free system. If the compressor has failed or the system’s been opened to atmosphere, moisture and debris can cause icing or sticking. That’s when a TXV can underfeed or overfeed, showing up as weak cooling at idle, a frosty evaporator outlet, hunting pressures, or hissing and temperature swings.

Replacement or diagnosis should be done with proper recovery equipment for R1234yf (A2L, mildly flammable) and by following Audi repair procedures. Typical best practice includes:

• Recovering refrigerant, then removing the valve and lines without stressing the pipes
• Replacing O-rings/seals with the correct Audi-approved items and lubricating with the specified A/C oil
• Leak testing (nitrogen/trace gas), deep vacuum, and recharging by mass as per the under-bonnet label
• Assessing the receiver-drier, on many late-model Audis it’s integrated with the condenser, so plan accordingly if the system’s been open

A workshop may also inspect for contamination. If there’s metal debris from a compressor failure, the TXV should be replaced along with thorough flushing (where allowed), a new drier, and correct oil balancing. Noises, intermittent cooling, or stubborn warm vent temps in stop–start traffic are a good prompt to pressure-test and check TXV operation with gauges and scan data. Done right, the Q5’s A/C returns to crisp, even cooling and consistent superheat control.

Does the 2019 Audi Q5 use a TX valve or an orifice tube?

It uses a thermostatic expansion valve at the evaporator. Audi’s FY-series air-con design pairs a TXV with a variable-displacement compressor, not an orifice tube/accumulator setup.

What are common signs the TX valve needs attention on a 2019 Q5?

Sluggish cooling at idle, frosty evaporator outlet line, rapid pressure fluctuations, or temperature swings at the vents. After a compressor failure, debris can also clog the TXV.

Should the TX valve be replaced during a routine regas?

Not typically. It’s replaced when faulty or contaminated. If the system has been open or moisture-laden, expect to service the drier and follow full evacuate, leak-test, and precise recharge steps.