2017 Kenworth T680 A/C Refrigerant & Oil Capacity

Quick Answer

• Refrigerant Type: R-134a
• Full System Charge: 48 oz (1360 grams)
• PAG Oil Type: PAG 46
• PAG Oil Amount: 8 oz (236 mL)
• Low-Side Service Port Location: Typically on the accumulator/drier, located on the passenger side of the engine bay, near the firewall.
• High-Side Service Port Location: Usually on the liquid line, a smaller diameter line running from the condenser to the expansion valve, often near the condenser or receiver drier.

Why R-1234yf Matters (Even for R-134a Systems)

While your 2017 Kenworth T680 uses R-134a refrigerant, it's important to understand the industry's transition to R-1234yf. Starting around 2014, many new vehicles began adopting R-1234yf due to its significantly lower Global Warming Potential (GWP) compared to R-134a. This shift was driven by environmental regulations and industry initiatives. Although your T680 isn't directly affected by the R-1234yf requirement, being aware of this change is crucial for several reasons:

• Cost: R-1234yf is considerably more expensive than R-134a.
• Environmental Impact: R-1234yf contributes less to global warming.
• Recovery Machine Requirements: R-1234yf systems require specialized recovery and charging equipment to prevent cross-contamination and ensure proper handling. While not applicable to your T680, it highlights the increasing complexity of A/C service.

Recharge Procedure

Recharging an A/C system is not as simple as just adding refrigerant until the gauges read a certain pressure. Proper A/C service requires precision and adherence to manufacturer specifications. Here's a high-level overview, emphasizing critical steps:

1. Evacuate the System: The most crucial step is to completely evacuate the A/C system using a vacuum pump. This removes all air and moisture, which can cause significant damage to the system components and reduce cooling performance. A deep vacuum (below 500 microns) should be held for at least 30-45 minutes to ensure all contaminants are boiled out.
2. Leak Test: Before recharging, the system must be thoroughly leak tested. Even a small leak can lead to refrigerant loss and repeated repairs. This can be done with a vacuum decay test, electronic leak detector, or UV dye.
3. Proper Charge by Weight: Always charge the system by weight, not by pressure. Using a highly accurate charging scale ensures the correct amount of refrigerant is added according to the manufacturer's specifications (48 oz or 1360 grams for your T680). Overcharging or undercharging can both lead to poor cooling performance, increased component wear, and potential compressor damage.
4. Add PAG Oil: If any components were replaced or oil was lost due to a leak, the appropriate amount and type of PAG oil (PAG 46, 8 oz/236 mL for your T680) must be added. Refer to service manuals for specific oil addition procedures based on component replacement.

Common A/C Problems for the Kenworth T680 (This Generation)

Owners of the 2017 Kenworth T680 may experience several common A/C issues:

• Compressor Failures: The A/C compressor is a high-wear item, and failures can occur due to lack of lubrication (low oil), contamination, or simply old age. Symptoms include noise, no cooling, or a seized compressor clutch.
• Condenser Issues: The condenser, located in front of the radiator, is susceptible to damage from road debris, leading to leaks. It can also become clogged with dirt and debris, restricting airflow and reducing cooling efficiency.
• Evaporator Leaks: The evaporator, located inside the cabin, can develop leaks over time. These are often difficult to diagnose as the leak is internal and may present as a musty odor or a slow refrigerant loss even after other components have been checked.
• Blower Motor Resistor Issues: While not directly a refrigerant issue, problems with the blower motor resistor can lead to intermittent or non-functional fan speeds, impacting the perceived effectiveness of the A/C system.

When to Call a Pro

Given the complexity and potential hazards associated with A/C system repair, it's often best to call a certified professional. Tampering with A/C systems without proper training and equipment can lead to:

• Personal Injury: Refrigerants can cause frostbite and other injuries. High pressures in the system can also be dangerous.
• Environmental Damage: Improper release of refrigerants (especially R-134a) contributes to greenhouse gas emissions and depletes the ozone layer.
• System Damage: Incorrectly diagnosing or repairing A/C problems can lead to more expensive repairs down the line, including compressor failure.

Safety Disclaimer: Working with automotive A/C systems requires specialized training, tools, and an EPA Section 609 certification for handling refrigerants legally and safely. Attempting repairs without proper knowledge and equipment can result in injury, environmental harm, and system damage. Always prioritize safety and environmental responsibility.

Find a certified A/C shop on Repairius.