Correction
CorrectionAluminum or Cast Iron Block - Oil in Intake Manifold - Install Updated Valve Cover on All Models Built Prior to February 1, 2011
Note
If vehicle is built after this breakpoint, it should already be equipped with this updated valve cover.
1) Old Design
2) New Design
PCV pullover or an overactive lifter can cause oil to be pulled through the PCV system even at low vehicle mileage. A correctly functioning PCV system will only leave a film of oil in the intake manifold. Inspect the intake manifold to see if there is any oil puddling in the bottom. If there is you will need to replace the left valve cover. Two new left rocker arm covers have been released for trucks and vans. Technicians should replace the left rocker arm cover with GM P/N 12570427 for 2007-2008 or GM P/N 12642655 for 2009-2011. Refer to the Parts Information below for the Camaro. This rocker arm cover has a relocated PCV drain hole that prevents oil from entering the intake manifold. Refer to Valve Rocker Arm Cover Replacement - Left Side in SI.
Note
These rocker covers are for specific years. The PCV orifice is different for each. The correct cover must be used or an SES light may set.
Aluminum Block - Oil Getting Past Piston Rings - Free Up Piston Rings and Install AFM Shield on All Non-Hybrid Models Built Prior to October 1, 2010 or all Hybrid Models Built July 7, 2009 - October 1, 2010
Note
If vehicle is built outside of this breakpoint, it should already be equipped with this AFM shield or the pan does not have an AFM valve (LFA before July 7, 2009).
To correct this condition, install an AFM shield, perform the piston cleaning procedure as described in this document and install a new oil pan gasket per the procedure outlined in this document. Monitor oil consumption after this repair to ensure oil consumption has improved to acceptable levels.
If this repair does not correct the condition, it may be necessary to replace all of the piston assemblies (piston and rings) with new parts. Refer to SI for repair procedure.
Important
It is critical in this cleaning process that the engine/fuel injector cleaner remain in the cylinders for a minimum of 2.5 hours to fully clean the components. The cleaner solution must be removed before a maximum of three hours.
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 Nm (20 lb ft).
Important
Ensure that the engine cleaner is thoroughly removed before reinstalling the spark plugs. Failure to do so may result in a hydro-lock condition.
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.
Important
Some minor scratches may be noticed on the cylinder walls during piston and ring replacement. If the scratch cannot be felt when running your finger nail over it, the scratch is considered normal wear and the block or engine should not be replaced.
Note
It is not necessary to hone or deglaze the cylinder walls. Honing may induce unnecessary cylinder wall and / or piston ring damage if it is done incorrectly and/or not cleaned thoroughly. Cylinder walls should cleaned thoroughly with brake cleaner before installation of the new pistons and rings. Numerous engines replaced for oil consumption have been inspected. The cross hatch has been consistently good and is in specification. As a result, is should not be necessary to measure the cylinders if they pass the visual inspection.
Note
After the piston/ring replacement it will take 2000-3000 mi. for the new rings to seat. Adequate break time is necessary prior to rechecking the oil consumption level.
Note
Do not overlook the valve seals at higher mileage. Look in the head ports for evidence of excessive amounts of oil getting past the seals.
Note
It is recommended to install an AFM shield any time that the oil pan is removed for any reason and an AFM shield is not found.
Cast-Iron Block - Oil Getting Past Piston Rings - Free Up Piston Rings on All Models Built Prior to October 1, 2010
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.
Important
Ensure that the engine cleaner is thoroughly removed before reinstalling the spark plugs. Failure to do so may result in a hydro-lock condition.
3. Reinstall the spark plugs. Replace the spark plugs if necessary due to full of carbon. Refer to the parts catalog.
4. 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.
Note
It is not necessary to install the shield when doing the piston cleaning on a cast iron block engine since the cast iron block engine uses a different oil pump than an aluminum block engine, which results in a higher engine speed before the AFM pressure relief valve opens (cast iron block engines are less prone to the AFM oil spray condition described earlier). If you find it necessary to replace the pistons and/or remove the oil pan for any other reason, only then should you add the shield.
Important
Some minor scratches may be noticed on the cylinder walls during piston and ring replacement. If the scratch cannot be felt when running your finger nail over it, the scratch is considered normal wear and the block or engine should not be replaced.
Note
It is not necessary to hone or deglaze the cylinder walls. Honing may induce unnecessary cylinder wall and / or piston ring damage if it is done incorrectly and/or not cleaned thoroughly. Cylinder walls should cleaned thoroughly with brake cleaner before installation of the new pistons and rings. Numerous engines replaced for oil consumption have been inspected. The cross hatch has been consistently good and is in specification. As a result, is should not be necessary to measure the cylinders if they pass the visual inspection.
Note
After the piston/ring replacement, it will take 2000-3000 miles for the new rings to seat. Adequate break time is necessary prior to rechecking the oil consumption level.
Note
Do not overlook the valve seals at higher mileage. Look in the head ports for evidence of excessive amounts of oil getting past the seals.
Note
It is recommended to install an AFM shield any time that the oil pan is removed for any reason and an AFM shield is not found.