The 2015 Chevy Sonic uses Dex-Cool, GM’s orange long-life coolant (an organic acid technology formulation). It should be used as a 50/50 mix with distilled water, or as a GM-approved Dex-Cool-compatible concentrate diluted to that ratio. Do not mix Dex-Cool with other coolant types unless the product explicitly states Dex-Cool compatibility.
Coolant type and specifications
For the Sonic, use Dex-Cool or a GM-approved Dex-Cool-compatible coolant. The system uses an OAT formulation typically orange in color. The factory fill is a 50/50 premix with distilled water, or you can purchase concentrate and dilute to the same ratio. Color alone isn’t a reliable guide, so always verify packaging for Dex-Cool or GM Dex-Cool compatibility.
Before listing the key points to consider when selecting and using the coolant, note these guidelines:
- Use Dex-Cool or a GM-approved Dex-Cool-compatible coolant (orange, OAT) and ensure it is labeled as Dex-Cool or GM Dex-Cool compatible.
- Mix to a 50/50 ratio with distilled water (premixed 50/50 is convenient). Avoid using tap water to prevent mineral deposits.
- Avoid mixing with green conventional, HOAT, or universal coolants unless the product explicitly states Dex-Cool compatibility for GM vehicles.
- If switching from a non-Dex-Cool coolant, plan a system flush to prevent deposits and ensure proper operation.
Using the correct Dex-Cool formulation helps protect cooling passages, the radiator, water pump, and engine seals from corrosion and overheating while reducing the risk of deposits that can form with incompatible coolants.
Choosing and purchasing the right product
Look for products labeled Dex-Cool, GM Dex-Cool, or Dex-Cool-compatible, and confirm they meet GM specifications for Dex-Cool. Approved options include brands that advertise Dex-Cool compatibility (often on the label). Premixed 50/50 versions are convenient and minimize the risk of incorrect dilution. Do not rely on universal coolants unless the label clearly indicates Dex-Cool compatibility for GM vehicles.
Maintenance and replacement intervals
GM generally recommends replacing Dex-Cool every 5 years or 150,000 miles, whichever comes first, but exact service intervals can vary by model and driving conditions. Always check your owner’s manual or consult a GM dealer for the specifics of your vehicle. If you notice overheating, leaks, or abnormal coolant color, have the cooling system inspected promptly.
Flushing and bleeding after a coolant change
After changing coolant, flush the system thoroughly and bleed air according to the service procedure to prevent air pockets and hot spots. Recheck the reservoir level and radiator cap, and top off with the correct 50/50 Dex-Cool mix if needed.
Summary
In short, the 2015 Chevy Sonic requires Dex-Cool (GM orange long-life coolant), used in a 50/50 mix with distilled water. Use GM Dex-Cool or an approved Dex-Cool-compatible product, and avoid mixing with non-Dex-Cool formulations. Refer to your owner’s manual or a Chevrolet dealer for the exact specification and replacement intervals for your specific engine and driving conditions.