2015 Jeep Wrangler Coolant Capacity & Type

The 2015 Jeep Wrangler (JK generation) holds approximately 10-13 quarts (9.5-12.3 liters) of coolant in its cooling system, depending on the engine and transmission configuration.

Quick answer

• Total Cooling System Capacity: 10-13 quarts (9.5-12.3 liters)
• OEM Coolant Spec: Mopar OAT (Organic Additive Technology) Coolant, Purple in color, Chrysler MS-12106 specification.
• Mix Ratio: Typically 50/50 pre-mix or concentrate mixed with distilled water.

Capacity by engine option

The 2015 Jeep Wrangler was primarily offered with one engine option in North America, the 3.6L Pentastar V6. However, capacity can vary slightly with transmission type (manual vs. automatic) and specific vehicle options like towing packages.

Always consult your owner's manual for the most precise capacity for your specific vehicle configuration.

Flush interval

For the 2015 Jeep Wrangler, Chrysler recommends a coolant flush and fill interval of 10 years or 150,000 miles, whichever comes first, under normal driving conditions. However, under severe duty conditions (e.g., frequent towing, off-roading, extreme temperatures, dusty environments), it's wise to consider changing the coolant more frequently, perhaps every 5 years or 75,000 miles.

Regularly inspect your coolant level and condition. If the coolant appears discolored, sludgy, or has debris in it, it's time for a flush regardless of mileage or time.

How to refill & bleed

Refilling and bleeding the cooling system on a 2015 Jeep Wrangler is crucial to prevent air pockets, which can lead to overheating. Always perform this procedure on a cool engine.

1. Drain the old coolant: With the engine cool, place a drain pan under the radiator. Open the radiator drain cock (petcock) usually located on the bottom of the radiator. Remove the radiator cap to allow for faster draining. For a more complete flush, you may want to remove the lower radiator hose as well.
2. Flush (optional but recommended): Once drained, close the drain cock/reconnect the hose. Fill the system with distilled water. Run the engine with the heater on high until it reaches operating temperature (thermostat opens). Allow it to cool, then drain. Repeat this process until the drained water runs clear. You can also use a dedicated cooling system flush product following its instructions.
3. Refill with new coolant: Close the drain cock/reconnect the hose. Begin filling the system slowly with the specified Mopar OAT MS-12106 coolant (50/50 mix). Fill the radiator and the coolant reservoir to the "FULL COLD" mark.
4. Bleed the system: This is a critical step for the 3.6L Pentastar engine.
   • Leave the radiator cap off. Start the engine and let it idle. Turn the heater to its maximum temperature and fan speed setting.
   • As the engine warms up, the thermostat will open, and coolant will begin to circulate. Watch for air bubbles to escape from the radiator fill neck. You may need to gently squeeze the upper and lower radiator hoses to help dislodge air.
   • Maintain the coolant level in the radiator by adding more coolant as needed. There is often a bleed screw or valve on the thermostat housing or an adjacent hose on the 3.6L engine that can be opened slightly to facilitate air escape. Loosen it until coolant (not just air) begins to flow out, then tighten it.
   • Continue this process until no more air bubbles appear in the radiator. Install the radiator cap.
5. Final check: Drive the vehicle and monitor the temperature gauge. After the engine cools completely, recheck the coolant level in the reservoir and top off if necessary. Repeat the bleed procedure if overheating signs occur or if the coolant level drops significantly.

Consider using a vacuum-fill tool for the most effective air removal, especially if you encounter persistent air pockets.

Common cooling system issues

Owners of 2015 Jeep Wranglers (JK generation) occasionally report several cooling system-related issues:

• Leaking Radiators: The plastic end tanks on the OEM radiators can become brittle over time, leading to cracks and leaks, especially around hose connections.
• Water Pump Failure: The water pump can develop leaks or bearing noises, requiring replacement. This is a common wear item on many vehicles.
• Oil Cooler/Filter Housing Leaks: This is a widely known issue on 3.6L Pentastar engines, where the integrated oil filter housing and oil cooler assembly, often made of plastic, can crack or develop leaks, allowing oil to mix with coolant or leak externally. This requires prompt attention as it can contaminate the cooling system and/or lead to oil loss.
• Thermostat Failure: The thermostat can fail, leading to either an engine that runs too hot (stuck closed) or takes a long time to warm up (stuck open).
• Heater Core Clogging (less common but possible): If maintenance is neglected or incorrect coolant is used, the heater core can become partially or fully clogged, resulting in poor cabin heating.

Regular inspection of hoses, clamps, and fluid levels can help catch these issues early.

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