The Cadillac CTS typically uses Dex-Cool Extended-Life coolant (the orange, OAT-based formula) that meets GM specification 1825M, usually sold in premixed 50/50 form. Always verify with your vehicle’s owner’s manual or the under-hood label for your exact year and engine configuration.
Dex-Cool is GM’s long-life coolant designed for aluminum engines and closed cooling systems. It’s important not to mix Dex-Cool with conventional green coolant or with other brands unless they explicitly state compatibility with Dex-Cool/GM 1825M, as improper mixing can cause deposits or corrosion. The CTS has used this Dex-Cool formulation across its production run, from the early 2000s through the mid-2010s.
Coolant Type by CTS Generations
The following generations share the same Dex-Cool requirement, but it’s always wise to confirm the exact specification and mixing form (premixed vs. concentrate) from the manual or a GM dealer.
- Gen 1 (2003–2007): Dex-Cool Extended-Life Coolant, GM specification 1825M; commonly available as premixed 50/50.
- Gen 2 (2008–2013): Dex-Cool Extended-Life Coolant, GM specification 1825M; commonly sold premixed in 50/50 form; avoid mixing with green coolant.
- Gen 3 (2014): Dex-Cool Extended-Life Coolant, GM specification 1825M; premixed 50/50 is typical, with the same mixing precautions.
In short, the Cadillac CTS uses Dex-Cool Extended-Life coolant (orange) meeting GM specification 1825M across its generations. Use premixed 50/50 or the GM-approved concentrate and distilled water as directed, and avoid mixing with non-Dex-Cool products.
Maintenance and Replacement Tips
When servicing or refilling, follow these guidelines: use GM Dex-Cool Extended-Life coolant that meets specification 1825M; choose premixed 50/50 if you want a simple fill, or use the concentrate with distilled water as per the label. Do not mix Dex-Cool with conventional green antifreeze or with other non-Dex-Cool formulas. If you are flushing the system, drain fully, flush with distilled water, then refill with Dex-Cool and run the engine to operating temperature to circulate the new coolant.
Summary
The Cadillac CTS requires Dex-Cool Extended-Life coolant (orange) that conforms to GM specification 1825M. This has been the standard across its generations, with premixed 50/50 solutions commonly available. Always verify the exact requirement for your model year in the owner’s manual and follow proper mixing, flushing, and maintenance guidelines to protect the engine and cooling system.