2018 GMC Yukon A/C Refrigerant and Oil Capacity

Quick Answer

• Refrigerant Type: R-1234yf
• Full System Charge: 22 oz (624 grams)
• PAG Oil Type: PAG 46
• PAG Oil Amount: 6.0 oz (180 mL)
• Low-Side Service Port: On the accumulator/drier, near the firewall on the passenger side.
• High-Side Service Port: On the refrigerant line, typically near the condenser on the passenger side, frequently closer to the front of the vehicle.

Why R-1234yf Matters

The 2018 GMC Yukon utilizes R-1234yf refrigerant, a significant change from the older R-134a. This transition, which began around 2014 for many manufacturers, was driven by environmental concerns. R-1234yf has a much lower Global Warming Potential (GWP) compared to R-134a, making it a more environmentally friendly choice. However, this comes with a few implications:

• Cost: R-1234yf is typically more expensive than R-134a.
• EPA Regulations: Due to its specific environmental properties, special EPA regulations govern the handling and recovery of R-1234yf. Technicians must be 609 certified to work with this refrigerant.
• Recovery Machine Requirements: R-1234yf requires specialized recovery and recharging equipment. Standard R-134a machines cannot be used, and cross-contamination of refrigerants must be avoided.

Recharge Procedure

Recharging your 2018 GMC Yukon's A/C system should be done with precision. It's crucial to understand that proper A/C system service involves much more than simply adding refrigerant until the pressures look "right" on a gauge. Overcharging or undercharging can both lead to poor performance and potential system damage.

Here's a high-level overview, but always refer to a service manual or consult a professional:

1. Recovery: The existing refrigerant must be safely recovered using a dedicated R-1234yf recovery machine.
2. Evacuation: The system needs to be evacuated with a vacuum pump to remove all air and moisture. Moisture in an A/C system can lead to corrosion and component failure.
3. Leak Testing: Before recharging, the system should be leak tested to ensure there are no breaches that would allow new refrigerant to escape.
4. Proper Charge by Weight: The correct amount of refrigerant, as specified above (22 oz or 624 grams), must be charged into the system by weight, not by pressure. This ensures optimal performance and longevity of the components. Likewise, the correct amount and type of PAG oil should only be added if components have been replaced or if it's determined to be low.

Common A/C Problems for this Vehicle

While the 2018 GMC Yukon is generally a reliable vehicle, certain A/C issues can arise with this generation:

• Compressor Failures: The A/C compressor is a critical component that can experience wear and tear, leading to reduced cooling or complete failure. Symptoms include a noisy compressor, lack of cold air, or a burning smell.
• Condenser Issues: The condenser, located at the front of the vehicle, can be susceptible to damage from road debris. A damaged condenser will not be able to dissipate heat effectively, leading to poor A/C performance.
• Evaporator Leaks: The evaporator core, located inside the dashboard, can develop leaks. These leaks are often difficult to diagnose without specialized tools and can lead to a gradual loss of refrigerant and noticeable odors in the cabin.
• Blend Door Actuator Failures: While not a refrigerant-specific issue, faulty blend door actuators can prevent proper air distribution or temperature control within the cabin, mimicking an A/C problem.

When to Call a Pro

Attempting complex A/C repairs without the proper tools, knowledge, and EPA 609 certification can be dangerous and harmful to the environment. You should call a professional if you experience any of the following:

• Your A/C system is not blowing cold air.
• You hear unusual noises when the A/C is running.
• There are visible leaks or strange smells coming from your A/C vents.
• You suspect a major component failure.

Safety Disclaimer: Working with automotive air conditioning systems involves high pressures and specialized refrigerants. Improper handling can lead to serious injury and harm to the environment. It is strongly recommended that all A/C system service and repairs be performed by a certified professional holding an EPA 609 certification for handling refrigerants.

Find a certified A/C shop on Repairius.