Audi A5 Air Conditioning Expansion Valve: A Guide for 2008-2017 Models
If your A5's air conditioning is blowing warm, the expansion valve could be the culprit, but don't overlook other common issues.
- Before replacing the expansion valve, have a mechanic investigate the A/C pressure/temperature sensor (G395), a common failure point on the Audi A5.
- This repair is not DIY-friendly as it requires specialized A/C service equipment for refrigerant recovery and recharging.
- Always replace the receiver-drier component at the same time as the expansion valve to protect the A/C system.
- Symptoms like warm air, inconsistent cooling, or frost on vents point towards an expansion valve issue.
Is Your Audi A5 A/C Blowing Warm Air?
When the air conditioning in your 2008-2017 Audi A5 stops blowing cold, it's a frustrating problem. One of the potential causes is a failed A/C expansion valve. This component can get stuck open or closed, disrupting the refrigerant flow needed to cool your car. A valve stuck open can flood the evaporator, while a stuck closed valve starves it.
Important: Check This Before Replacing Your Expansion Valve
For the 2008-2017 Audi A5 and related models (A4, Q5), A/C failure is frequently misdiagnosed. A Technical Service Bulletin (TSB A871449) 🎬 Watch: Diagnosing the G395 pressure sensor fault points to the A/C pressure/temperature sensor (G395) as a common failure point. This sensor can leak refrigerant or send incorrect signals, causing the A/C compressor to shut down. Symptoms are identical to a bad expansion valve (A/C blowing warm or not working at all 🎬 See how to fix the 00256 error code). Have a technician check the G395 sensor and its wiring before committing to a more expensive expansion valve replacement.
Symptoms of a Failing A/C Expansion Valve
- Warm Air from Vents: The most common symptom is warm or lukewarm air from the vents, even when the A/C is set to max cold.
- Inconsistent Temperatures: The air may cycle between cool and warm.
- Frost on Vents or A/C Lines: If the valve is stuck open, it can allow too much refrigerant into the evaporator, causing it to freeze. You might see frost on the vents or A/C components.
- A/C Compressor Runs Constantly: A valve that is stuck may cause the compressor to run non-stop, trying to reach the target temperature.
- Complete System Shutdown: In some cases, a blocked valve can cause the system to shut down entirely.
Choosing the Right Aftermarket Expansion Valve
When replacing the expansion valve, you have a choice between OEM and aftermarket parts. The OEM part for your A5 costs significantly more than aftermarket options. For a part that requires extensive labor to replace, quality is key. However, good aftermarket options exist that can save you money.
Aftermarket Brand Tiers
- Tier 1 (OEM Equivalents): Brands like Behr Hella are often original equipment suppliers to Audi. Choosing these parts gives you OEM quality without the dealer markup.
- Tier 2 (Quality Aftermarket): Nissens and Four Seasons are well-known aftermarket brands. New parts from Four Seasons are generally considered a reliable budget-friendly choice. However, some forum users have reported that Nissens A/C components can sometimes have minor fitment issues that require small modifications.
- Tier 3 (Economy Brands): Global Parts Distributors (GPD) and other lower-cost brands are available. While the price is low, quality and longevity can be inconsistent. Given the high labor cost for this repair, saving a few dollars on the part itself can be a risky choice.
Pro Tip: Replace the Receiver-Drier
Anytime the A/C system is opened for a repair like this, you MUST replace the receiver-drier (also called an accumulator). This component absorbs moisture from the refrigerant. A new, dry one is essential for the health and longevity of your new expansion valve and the entire A/C system. Failing to replace it can void the warranty on your new parts.
Cost to Replace the Audi A5 A/C Expansion Valve
The total cost depends heavily on shop labor rates. The job requires specialized equipment to recover and recharge the refrigerant.
| Part/Service | Estimated Cost |
|---|---|
| New OEM Part | $175 - $255 |
| New Aftermarket Part | $28 - $150 |
| Shop Labor | $122 - $304 |
| Total Estimated Cost | $250 - $550+ |
Costs are estimates and can vary by location and the specific condition of your vehicle. Total cost includes the part, labor for replacement, and A/C system evacuation and recharge.
Frequently Asked Questions
Can I replace the A/C expansion valve myself?
This is not recommended for most DIY mechanics. The job requires recovering the A/C refrigerant before starting and then using a vacuum pump and manifold gauges to properly evacuate and recharge the system afterward. Failure to do this correctly will result in poor performance and can damage components. It's best left to a qualified technician with the right tools.
Where is the expansion valve located on the 2008-2017 Audi A5?
The expansion valve is located on the vehicle's firewall in the engine bay. It's where the two aluminum A/C lines connect to the evaporator core, which passes through to the dashboard. On the B8 platform A5, it can be accessed from under the hood, which is easier than jobs that require removing the dashboard.
My mechanic says the expansion valve is fine, but my A/C is still not cold. What else could it be?
On the Audi A5, a very common cause is a faulty A/C pressure/temperature sensor (G395), as noted in a factory TSB. Other potential issues include a refrigerant leak, a failing compressor, or an electrical problem. 🎬 Watch: Professional diagnosis for a faulty A/C compressor Always start with a full system diagnosis from a qualified technician.
Do I need to add oil when replacing the expansion valve?
Yes, but only a very small amount. The new O-rings for the valve connections should be lubricated with the correct type of A/C oil (PAG oil) to ensure a proper seal. When a professional recharges the system, they will add the correct amount of oil to compensate for what was lost during the repair.
Helpful Videos
Technical Specifications
OEM Part Numbers: 8K0-820-679-B 8k0820679a 8T0 820 679 A
Block-type thermal expansion valve for R134a refrigerant systems. Located on the firewall in the engine bay.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Audi A5:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your Audi A5 A/C Blowing Warm Air?
- Important: Check This Before Replacing Your Expansion Valve
- Symptoms of a Failing A/C Expansion Valve
- Choosing the Right Aftermarket Expansion Valve
- Aftermarket Brand Tiers
- Pro Tip: Replace the Receiver-Drier
- Cost to Replace the Audi A5 A/C Expansion Valve
- Frequently Asked Questions
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