2017 Kenworth T680 Coolant Capacity & Type

The 2017 Kenworth T680 typically holds between 60 to 75 quarts (approximately 56 to 71 liters) of coolant in its cooling system, depending on the specific engine and cooling system configuration.

Quick Answer

• Total Cooling System Capacity: 60-75 quarts (56-71 liters)
• OEM Coolant Spec: PACCAR Approved ELC (Extended Life Coolant), often red or pink in color, meeting ASTM D6210 and TMC RP 329 standards. This is an OAT (Organic Acid Technology) coolant.
• Mix Ratio: 50/50 prediluted or 50% concentrate with 50% deionized water.

Capacity by Engine Option

The Kenworth T680 in 2017 was available with a few different engine options, each having slightly varying coolant capacities. The primary engines were the PACCAR MX-13 and Cummins X15.

These figures are estimates and can vary based on radiator size, presence of auxiliary heaters, and other cooling system components. Always refer to your Kenworth T680's owner's manual for the precise capacity for your specific configuration.

Flush Interval

For the 2017 Kenworth T680 using PACCAR Approved ELC, the flush interval is significantly extended compared to traditional coolants:

• Normal Duty: Up to 600,000 miles, 12,000 hours, or 6 years, whichever comes first.
• Severe Duty (e.g., heavy hauling, frequent idling, extreme temperatures): It's advisable to check the coolant condition more frequently (e.g., annually) and consider a flush and refill at slightly reduced intervals, such as 400,000 miles or 4 years, or as indicated by coolant analysis.

Regularly checking coolant levels and condition, and performing coolant analysis, can help determine the optimal flush interval and identify potential issues before they become severe.

How to Refill & Bleed

Refilling and bleeding the cooling system on a heavy-duty truck like the Kenworth T680 requires careful attention to ensure all air is removed, which is critical for proper cooling.

1. Drain the System: Ensure the engine is cool. Open the petcock on the bottom of the radiator and any drain plugs on the engine block. Collect all old coolant in a suitable container for proper disposal.
2. Flush (Optional but Recommended): If performing a full flush, close drain points, fill with distilled water and a cooling system cleaner (if needed), run the engine to operating temperature with the heater on high, then drain again. Repeat with plain distilled water until the drained water is clear.
3. Close Drains: Securely close all drain plugs and the radiator petcock.
4. Fill with New Coolant: Slowly pour the specified PACCAR ELC (50/50 mix) into the expansion tank or surge tank. Fill until the coolant level is between the "cold fill" marks.
5. Bleed the System:
   • Start the engine and run it at a fast idle (around 1000-1200 RPM) with the expansion tank cap off (or slightly loosened if it's a sealed system with an overflow).
   • Monitor the coolant level in the expansion tank and add more as it drops. Air will be purged through the tank.
   • Turn on the cab heater to its highest setting to open the heater core valve and allow coolant to circulate through it, helping to purge air from that part of the system.
   • Many Kenworth trucks do not have specific bleed screws; the design relies on the expansion tank to facilitate air purging. In some cases, a specialized vacuum fill tool may be necessary, especially after a major component replacement, to ensure all air is removed efficiently.
   • Continue running the engine and adding coolant until the level stabilizes and no more air bubbles appear in the expansion tank. This can take 20-30 minutes or more.
6. Final Check: Once the engine is at operating temperature and the thermostat is open, shut off the engine. Allow it to cool completely. Recheck the coolant level and top off if necessary. Keep an eye on the coolant level over the next few drive cycles.

Common Cooling System Issues for this Generation

Owners of 2017 Kenworth T680s, like other heavy-duty trucks, may encounter several common cooling system issues:

• Coolant Leaks: Due to the extensive plumbing and numerous connections, leaks can occur from hoses, hose clamps, the radiator, water pump, or EGR cooler. Regular visual inspections are vital.
• EGR Cooler Failure: The Exhaust Gas Recirculation (EGR) cooler is a common failure point in many modern diesel engines, including those found in the T680. A failing EGR cooler can lead to coolant loss, white smoke from the exhaust, and engine damage if not addressed promptly.
• Radiator Fan Clutch Issues: Problems with the fan clutch can lead to the engine overheating in slow-moving traffic or at idle if the fan isn't engaging correctly, or excessive noise and reduced fuel economy if it's stuck on.
• Thermostat Failure: A stuck-open thermostat can cause the engine to run too cool, leading to reduced fuel efficiency and improper emissions control. A stuck-closed thermostat will cause rapid overheating.
• Water Pump Failure: The water pump is critical for circulating coolant. Failure, often indicated by leaks, bearing noise, or overheating, requires immediate replacement.
• Coolant Contamination/Degradation: Using incorrect coolant, mixing different types, or neglecting the flush interval can lead to silicate dropout, gel formation, and corrosion, severely compromising the cooling system's effectiveness and longevity.

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