Manufacturer communication — 2006 GMC YUKON DENALI XL

• The model list names 2000–2019 Yukon XL.

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  2000–2019 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 6400 km (4000 mi); the only exception is an engine reported to use more than 0.946 liter (1 qt) in 1600 km (1000 mi).

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   Therefore, oil economy should not be tested until the vehicle has accumulated at least 6400 km (4000 mi). An exception would be allowed only if an engine is reported to be using more than 0.946 liter (1 qt) in 1600 km (1000 mi).

5. Check the oil level and record the vehicle mileage, date and exact oil level on the form in the bulletin, then make sure the oil level is at, but not above, the full mark on the dipstick.

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   Check the oil level and record the vehicle mileage, date, and exact oil level on the form included in this bulletin. Next ensure the oil level is at, but not above, the full mark on the dipstick.

6. Ask the customer to schedule an appointment and return for inspection once 100 gallons (= 378.5 L) of fuel have been consumed.

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   Ask the customer once they have consumed 100 gallons of fuel schedule an appointment and return to the dealer for inspection.

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.

Parts

• For powertrain warranty, labor operation 0600334 is Oil Consumption Test, 0.5 hr.

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  0600334* Oil Consumption Test 0.5 hr

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.