Manufacturer communication — 2006 GMC YUKON XL

• The model list names 2000-2015 GMC Savana, Sierra 2500/3500 and Yukon XL.

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  2000-2015 GMC Savana, Sierra, 2500/3500, Yukon XL

• It applies to vehicles with a gasoline engine rated at 8600 GVW and above.

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  with Gasoline Engine and Rated at 8600 GVW and above

Possible causes

• Oil usage is directly related to the amount of fuel used: the harder an engine works, the more fuel and oil it will use.

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  Oil usage has a direct relationship with the amount of fuel used. The harder an engine works, the more fuel and oil it will use.

• Towing a trailer or hauling additional weight will increase oil consumption.

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  Towing a trailer or hauling additional weight will increase oil consumption.

Steps to confirm (in the document’s order)

1. Inspect the oil pans, engine covers and engine oil cooler for leakage, and inspect for oil leakage into the engine coolant.

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   Inspect the oil pans, engine covers, and the engine oil cooler for leakage. Inspect for oil leakage into the engine coolant.

2. Let the vehicle sit for at least 15 minutes after the engine is shut off before reading the oil level, so the oil can drain back into the crankcase.

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   The vehicle should be allowed to sit for at least 15 minutes, after the engine has been shut off, before taking an oil level reading to assure the oil has had enough time to drain back into the crankcase.

3. Verify that the PCV system is operating properly; blockages, restrictions or damage to it can result in increased oil use.

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   Verify that the positive crankcase ventilation (PCV) system is operating properly. Blockages, restrictions or damage to the PCV system can result in increased oil use.

4. Oil economy should not be tested until the vehicle has accumulated at least 8000 km (5000 mi) and the oil has been changed for the first time.

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   Therefore, oil economy should not be tested until the vehicle has accumulated at least 8000 km (5000 mi) and the oil has been changed for the first time.

5. In the consumption test the customer operates the vehicle until the oil level drops to or below the add mark or at least 4800 km (3000 mi) has accumulated since the test began, then returns for a final evaluation.

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   If the oil level remains above the add mark, the customer should continue to operate the vehicle and verify the engine oil level until either the oil level drops to or below the add mark or at least 4800 km (3000 mi) has accumulated since the test began before returning to the dealership for a final evaluation.

Repair

• If the final evaluation shows more than 0.946 liter (1 qt) used in 379 liters (100 gallons) of fuel, follow the published symptom diagnostics in the appropriate Service Manual.

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  If the final evaluation shows that the engine uses more than 0.946 liter (1 qt) in 379 liters (100 gallons) of fuel used, follow the published symptom diagnostics as described in the appropriate Service Manual.

Caution

• The accepted rate of oil consumption for gasoline engines in vehicles at or above 8600 GVW is 0.946 liter (1 qt) within 379 liters (100 gallons) of fuel used.

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  The accepted rate of oil consumption for gasoline engines in vehicles at or above 8600 GVW is 0.946 liter (1 qt) within 379 liters (100 gallons) of fuel used.