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2018 XT4 Coolant Flush - Overheating Concerns & Type

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Mike T. · rep 0 · May 25, 2:54 AM · 1 replies · solved · Question

Vehicle: 2018 Cadillac XT4 Luxury

My 2018 Cadillac XT4 Luxury has about 70k miles now. Lately, the engine temperature seems a bit higher than usual, especially in stop-and-go traffic. I'm thinking it might be time for a coolant flush.

What's the recommended coolant type for the XT4? Is this something I can tackle myself, or should I take it to a shop? Any specific things to watch out for, like air pockets after refilling? No warning lights yet, but I want to be proactive.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:54 AM

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ClearTheCode admin answer:

It's smart to be proactive about your 2018 Cadillac XT4's cooling system, especially with 70,000 miles and noticing slightly higher temperatures. A coolant flush is a critical part of preventative maintenance.

  1. Coolant Type: Your XT4 requires Dex-Cool (Orange) extended-life Organic Acid Technology (OAT) coolant. It's crucial to use only Dex-Cool compatible fluid. Mixing different types of coolants can lead to chemical reactions that form sludge, clog the system, and cause significant damage. Always use a 50/50 pre-mixed solution or dilute concentrated Dex-Cool with distilled water.
  2. Service Interval: For Dex-Cool, the typical interval is 5 years or 150,000 miles, whichever comes first. However, if you're experiencing higher temperatures, it's a good time to service it.
  3. DIY Difficulty: A coolant flush can be a DIY job, but it requires careful attention to detail to avoid air pockets and ensure proper bleeding. Here are the basic steps:
    • Drain: With the engine cool, drain the old coolant from the radiator drain cock and potentially engine block drains (if accessible).
    • Flush: Refill with distilled water, run the engine with the heater on, then drain again. Repeat until the drained water is clear. You can use a dedicated cooling system flush product if desired, following its instructions carefully.
    • Refill: Fill the system with the correct 50/50 Dex-Cool mixture.
    • Bleed Air: This is crucial. Run the engine with the radiator cap off (or reservoir cap open) until the thermostat opens and coolant circulates. Squeeze radiator hoses to help release trapped air. You may need to use a specialized 'no-spill' funnel to aid in this process. Keep the heater on full blast to ensure coolant flows through the heater core.
    • Monitor: Drive the vehicle and monitor the temperature gauge closely for the next few days. Top off the reservoir as needed once the system has fully purged air.
  4. When to See a Shop: If the higher temperatures persist after a flush, or if you notice any of these symptoms, it's time to see a professional:
    • OBD Codes: Check for codes like P0128 (Coolant Thermostat (Coolant Temp Below Regulating Temperature)) or P0117 (Engine Coolant Temperature Sensor 1 Circuit Low).
    • Persistent Overheating: If the gauge goes into the red zone.
    • Coolant Leaks: Visible puddles or low reservoir levels without explanation.
    • Heater Issues: No heat inside the cabin, which can indicate an air pocket or a failing heater core.
    • A shop can perform a pressure test, diagnose thermostat or water pump issues, and ensure a thorough system bleed.
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