Manufacturer communication — 2006 GMC YUKON XL

• Applies to 2000-2019 GMC Savana, Sierra 2500/3500 and Yukon XL (note: the Yukon XL years run later than the years this service covers).

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  2000-2019 GMC Savana, Sierra, 2500/3500, Yukon XL

• Vehicles with a gasoline engine and rated at 8600 GVW and above are covered.

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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 uses.

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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 increases 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. The accepted oil consumption rate 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.

2. Inspect the oil pans, engine covers and engine oil cooler for leakage, and check for oil leaking 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.

3. 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.

4. Verify that the positive crankcase ventilation (PCV) system is operating properly; blockages, restrictions or damage can increase 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.

5. Start the oil consumption test after the next regularly scheduled oil and filter change, and do not change the oil during the test.

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   Begin oil consumption test after next regularly scheduled oil and filter change. Oil changes should not be performed during the test.

Repair

• If the final evaluation shows the engine uses more than 0.946 liter (1 qt) 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

• 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.

• If the test shows the engine uses less than 0.946 liter (1 qt) in 379 liters (100 gallons) of fuel, explain to the customer that the engine meets the oil consumption guidelines.

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  If the oil consumption test shows that the engine uses less than 0.946 liter (1 qt) in 379 liters (100 gallons) of fuel used, explain to the customer that their engine meets the guidelines for oil consumption.