The 2008 Cadillac CTS uses Dex-Cool Extended-Life coolant (orange HOAT). It is typically mixed 50/50 with distilled water and should be replaced according to GM maintenance intervals.
Recommended coolant options for the CTS
To stay within GM's Dex-Cool requirements, use one of these Dex-Cool-compatible formulations. They are available as premixed 50/50 or as concentrates that you dilute with distilled water.
- Dex-Cool Extended Life coolant (orange, HOAT) formulated for GM vehicles.
- GM-approved Dex-Cool compatible alternatives from major brands (e.g., Prestone Extended Life Dex-Cool, Zerex Dex-Cool), labeled as Dex-Cool/GM compatible and HOAT.
- A universal HOAT coolant that explicitly states Dex-Cool/GM compatibility on the label or product sheet.
When selecting coolant, ensure the product is Dex-Cool compatible and intended for GM engines. Do not mix with conventional green coolant unless the product documentation confirms compatibility.
Maintenance and handling tips for Dex-Cool
Keep the CTS cooling system performing well by following these practical guidelines.
- Check coolant level when the engine is cold and the vehicle is on level ground; keep the level between the Min and Max marks on the reservoir.
- Use distilled water for any dilution; avoid tap water which can introduce minerals.
- Avoid mixing Dex-Cool with non-Dex-Cool or green coolant unless the label explicitly states compatibility; incompatible mixing can lead to gel formation and reduced cooling efficiency.
- Replace or flush the cooling system per GM guidelines (commonly every 5 years or 150,000 miles, depending on the service interval), using Dex-Cool as the coolant.
- Inspect hoses, clamps, radiator, and water pump for leaks during routine maintenance; Dex-Cool leaks should be addressed promptly.
Following proper handling helps maintain cooling performance and engine longevity.
Summary
The 2008 Cadillac CTS requires Dex-Cool Extended-Life coolant (orange, HOAT), typically used in a 50/50 mix with distilled water. Use GM-approved Dex-Cool formulations or brands clearly labeled as Dex-Cool/GM compatible. Do not mix with green or non-Dex-Cool coolants unless compatibility is confirmed. Refer to the owner's manual or a GM-certified technician for the exact maintenance intervals.