The 2006 Hummer H3 uses GM Dex-Cool, a long-life, orange coolant that is typically used as a premixed 50/50 solution with distilled water. This is the GM-approved choice for the H3’s cooling system and should not be replaced with conventional green coolant.
Coolant Type and Compatibility
Before you buy coolant, note the key points about the type, mix, and compatibility for the H3’s cooling system.
- Coolant specification: Dex-Cool, GM-approved long-life coolant based on Organic Acid Technology (OAT).
- Color and identification: typically orange in color, designed to be distinct from traditional green coolant.
- Mixing ratio: most installations use a 50/50 mix with distilled water, though premixed Dex-Cool is commonly available.
- Compatibility: do not mix Dex-Cool with conventional green or silicate-based coolants, as improper mixing can cause corrosion or sludge.
- Where to obtain: use Dex-Cool or an equivalent GM-approved OAT coolant that explicitly states compatibility with Dex-Cool systems.
- Service interval: Dex-Cool is designed for extended service, typically around 5 years or 150,000 miles, whichever comes first, under normal conditions.
Using the correct coolant is essential to maintaining the H3’s cooling system and preventing leaks, corrosion, or overheating. If you’re unsure, confirm the exact specification with a GM dealer or by consulting the owner’s manual for your vehicle’s engine code and regional guidelines.
Maintenance tips and mixing guidelines
If you’re planning a coolant replacement or level check, follow these guidelines to ensure a proper, safe process.
- Ensure the engine is completely cool before opening the cooling system to avoid scalding from pressurized coolant.
- Drain the old coolant from the radiator and engine block using the lower radiator drain plug or petcock, if accessible.
- Optionally flush the system with a GM-approved coolant flush product and water to remove old coolant and deposits.
- Refill with the correct Dex-Cool or GM-approved OAT coolant in a 50/50 mix with distilled water, or use a premixed 50/50 Dex-Cool solution.
- Bleed air from the cooling system as required, replace the radiator cap if needed, and run the engine to operating temperature to ensure proper circulation.
- Check for leaks and top off coolant as necessary to maintain the proper level in the reservoir.
- Dispose ofUsed coolant at a proper recycling facility and never pour it down the drain or onto the ground.
Note: Always follow the exact procedures and torque specifications found in the owner’s manual, as procedures can vary slightly by model year or engine variant.
Summary
In brief, a 2006 Hummer H3 takes Dex-Cool, GM-approved orange long-life coolant based on Organic Acid Technology. Use a 50/50 mix with distilled water unless premixed, and avoid mixing Dex-Cool with green or other non-OAT coolants. Adhere to the maintenance intervals and consult the owner’s manual or a GM dealer if you’re unsure about specifications for your specific vehicle.