2017 Peterbilt 579 A/C Refrigerant and Oil Specifications

Quick Answer

• Refrigerant Type: R-134a
• Full System Charge: 4.5 lbs (72 oz)
• PAG Oil Type: PAG 46
• PAG Oil Amount: 10.8 oz (320 mL)
• Low-Side Service Port Location: Near the firewall on the passenger side
• High-Side Service Port Location: Near the condenser on the driver side

Why R-1234yf Matters

While the 2017 Peterbilt 579 uses R-134a, it's important to be aware of the newer R-1234yf refrigerant. Starting in 2014, the EPA began phasing out R-134a due to its high global warming potential. R-1234yf is a more environmentally friendly alternative, but it's also more expensive and requires special recovery machines. Always double-check the refrigerant type before servicing any vehicle, as mixing refrigerants can cause damage to the A/C system.

Recharge Procedure

A proper A/C recharge is about more than just adding refrigerant. It's crucial to follow the correct procedure to ensure the system functions correctly and to prevent damage.

1. Evacuate the system: Before adding any refrigerant, the system must be evacuated to remove any air or moisture. This is done with a vacuum pump.
2. Charge by weight: The only way to ensure the correct amount of refrigerant is in the system is to charge it by weight. This is done with a charging scale.
3. Don't charge by pressure: Charging by pressure is not an accurate way to fill an A/C system. The pressure can vary depending on the ambient temperature, so it's not a reliable indicator of the amount of refrigerant in the system.

Common A/C Problems for This Vehicle

• Compressor failures: The A/C compressor is a common failure point on the Peterbilt 579. The compressor can fail due to a variety of reasons, including a lack of lubrication, a refrigerant leak, or a clogged orifice tube.
• Condenser issues: The condenser is another common failure point. The condenser can be damaged by road debris, or it can fail due to a clog.
• Evaporator leaks: The evaporator is located in the cab of the truck, and it can be difficult to access. Evaporator leaks are often caused by corrosion.

When to Call a Pro

If you're not comfortable performing your own A/C repairs, it's best to call a professional. A certified A/C technician will have the tools and experience to properly diagnose and repair your A/C system.

Disclaimer: It is illegal to work on A/C systems without EPA 609 certification. If you are not certified, please take your vehicle to a certified technician.

Find a certified A/C shop on Repairius.