Download Install AFM Oil Deflector 2007-2014 GMC Sierra 1500 – 1. Remove the spark plugs and ensure that none of the pistons are at top dead center (TDC). 2. Clean the pistons by putting 118-147 ml (4-5 oz) of Upper Engine and Fuel Injector Cleaner, GM P/N 88861803 (in Canada, use 88861804), in each cylinder. Allow the material to soak for at least 2.5-3.0 hours, but no more than three hours and then remove the cleaner. A suggested method of removing the cleaner is cranking the engine over. Make sure to unplug the ignition coils and fuel injector before cranking the engine over. Also make sure that the painted surfaces are covered so no damage is done. 3. Remove the oil pan. Refer to Oil Pan Replacement in SI. 4. Remove the AFM valve (1). 5. Install the new shield (1), GM P/N 12639759, and tighten the AFM valve to the oil pan to 28 N.m (20 lb ft). 6. Reinstall the spark plugs. Replace the spark plugs if necessary due to full of carbon. Refer to the parts catalog. 7. Reinstall the oil pan. Refer to the Oil Pan Installation procedure in SI. Replace the oil pan gasket if necessary. Refer to the parts catalog. Replace the engine oil. 8. Re-evaluate the oil consumption. Document on the repair order. If the oil consumption is still greater than 0.946 L (1 qt) in 3,200 km (2000 mi), replacement of the pistons and rings will be required.