Manufacturer communication — 2006 GMC YUKON DENALI XL

• 2015 and prior GM passenger cars and trucks.

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  2015 and Prior GM Passenger Cars and Trucks

Possible causes

• Abrasive pads produce fine grit that the oil filter cannot remove from the oil; this grit is abrasive and has been known to cause internal engine damage.

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  Abrasive pads will produce fine grit that the oil filter will not be able to remove from the oil. THIS GRIT IS ABRASIVE AND HAS BEEN KNOWN TO CAUSE INTERNAL ENGINE DAMAGE.

• Abrasive pads can easily remove enough material to round cylinder head surfaces, which affects gasket sealing, especially in the narrow areas between combustion chambers and coolant jackets.

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  Abrasive pads can easily remove enough material to round cylinder head surfaces. This has been known to affect the gasket's ability to seal, especially in the narrow seal areas between the combustion chambers and coolant jackets.

• An abrasive pad removes 0.203 mm (0.008 in) of metal in about 15 seconds.

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  It takes about 15 seconds to remove 0.203 mm (0.008 in) of metal with an abrasive pad.

• Aluminum Oxide in the engine oil causes premature engine bearing failure, in some cases in as little as 2,200 km (1,367 mi) or less after the repair.

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  The presence of Aluminum Oxide in engine oil has been shown to cause premature engine bearing failure. In some cases, this failure occurs in as little as 2,200 km (1,367 mi) or less after the repair has been made.

Repair

1. GM recommends a razor blade or plastic gasket scraper to clean the gasket surface on engine components that are to be reused.

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   General Motors recommends the use of a razor blade or plastic gasket scraper to clean the gasket surface on engine components that are to be reused.

2. With a razor blade scraper, use a new blade for each cylinder head and corresponding block surface, and hold the blade as parallel to the gasket surface as possible.

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   When using a razor blade type gasket scraper, use a new razor blade for each cylinder head and corresponding block surface. Hold the blade as parallel to the gasket surface as possible.

3. Alternatively, spray GM Low VOC Cleaner, P/N 19287401 (in Canada, P/N 88901247), on the mating surface.

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   To properly clean the sealing surface prior to reassembly, GM Low VOC Cleaner, P/N 19287401 (in Canada, P/N 88901247), should be sprayed on the mating surface.

4. Let it soak for several minutes to loosen the old RTV sealer/gasket material, then remove the loose material with a plastic razor blade or non-metallic scraper.

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   Allow it to soak in for several minutes to loosen the old RTV sealer/gasket material. GM strongly recommends using a plastic razor blade or non- metallic scraper to remove all loose sealer/ gasket material.

Caution

• Do not use abrasive pad/bristle devices to clean the gasket surfaces of engine components.

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  Do not use abrasive pad/bristle devices to clean the gasket surfaces of engine components.

• The appearance of the gasket surface is not critical, the feel is; indentations left by the old gasket in the cylinder head will be filled by the new gasket.

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  The appearance of the gasket surface is not critical — the feel is. There will be indentations from the gasket left in the cylinder head after all the gasket material is removed. The new gasket will fill these small indentations when it is installed.