2019 Kenworth T680 A/C Refrigerant & Oil Capacity

Quick Answer

• Refrigerant Type: R-134a
• Full System Charge: 36-40 oz (1020-1134 grams)
• PAG Oil Type: PAG 100
• PAG Oil Amount: 8-10 oz (236-295 mL)
• Low-Side Service Port: Typically located on the accumulator/drier, near the firewall on the passenger side.
• High-Side Service Port: Usually found on the refrigerant line between the condenser and the expansion valve, often near the front of the engine compartment.

Why R-1234yf Matters (and Why Your T680 Uses R-134a)

While newer passenger vehicles, especially those manufactured after 2014, have transitioned to R-1234yf refrigerant due to its lower global warming potential (GWP), heavy-duty trucks like your 2019 Kenworth T680 largely continued to use R-134a. R-1234yf is a more environmentally friendly option, but it comes with higher costs for the refrigerant itself, and it requires specialized recovery and charging equipment. For now, the heavy-duty sector has had a slower adoption rate for R-1234yf, meaning your T680 will utilize the familiar R-134a.

Recharge Procedure for Your Kenworth T680

Recharging an A/C system isn't as simple as just adding a can of refrigerant until it feels cold. Proper procedure is crucial for system longevity and efficiency. Here's a high-level overview:

1. Evacuation is Key: Before adding any new refrigerant, the system must be evacuated using a vacuum pump. This process removes all air and moisture from the system, which can cause significant damage and reduce cooling performance.
2. Charge by Weight, Not Pressure: Always charge the system with the exact amount of refrigerant specified by the manufacturer (36-40 oz for your T680). This requires an accurate refrigerant charging machine. Using pressure gauges alone to determine the charge can lead to over or undercharging, both of which are detrimental to the system.
3. PAG Oil Considerations: If components are replaced (e.g., compressor, condenser), it's essential to add the correct type and amount of PAG 100 oil to compensate for any oil lost during the repair. Refer to service manuals for specific component oil amounts.

Common A/C Problems for Kenworth T680s

Heavy-duty trucks endure demanding conditions, and their A/C systems are no exception. Here are some common issues you might encounter with a Kenworth T680:

• Compressor Failures: The compressor is the heart of the A/C system. Common causes of failure include insufficient lubrication (low oil or incorrect oil type), contamination in the system, or simply wear and tear from extensive operating hours.
• Condenser Issues: The condenser, located in front of the radiator, is vulnerable to damage from road debris. Fins can become clogged with dirt and bugs, reducing heat exchange efficiency and leading to poor cooling. Leaks can also develop from impacts.
• Evaporator Leaks: The evaporator, located inside the cab, can develop leaks over time. These are often difficult to diagnose without specialized tools and typically manifest as a gradual loss of refrigerant and reduced cooling.
• Hose and Fitting Leaks: Vibrations and extreme temperatures can cause A/C hoses and fittings to degrade and leak. These are often easier to spot with UV dye in the system.

When to Call a Pro

While knowing your system's specifications is helpful, A/C system repairs and recharges are best left to EPA Section 609 certified technicians. This is due to several critical factors:

• Refrigerant Handling: Refrigerants are regulated substances that can harm the environment if released. Certified technicians have the proper equipment for recovery and recycling.
• Specialized Tools: Accurate vacuum pumps, charging stations, leak detectors, and diagnostic equipment are essential for proper A/C service.
• System Complexity: Modern A/C systems are complex. A professional can accurately diagnose issues, perform repairs, and ensure the system is charged to precise specifications, preventing further damage.

Safety Disclaimer: Working with automotive air conditioning systems involves high pressures and refrigerants that can cause frostbite and chemical burns. Always wear appropriate personal protective equipment, including eye protection and gloves. Never vent refrigerant into the atmosphere.

Find a certified A/C shop on Repairius.