Engine oil is exposed to extreme conditions, being used as both a lubricant and coolant inside the engine. Exposure to extreme pressure, heat, and contaminants such as exhaust soot and diesel fuel degrade its chemical and mechanical properties, necessitating frequent oil changes. Engine oil should be replaced every 10,000 miles or as indicated by the instrument cluster display. Frequent towing, idling, and severe climate driving will necessitate more frequent service.
Applicable model years: 2001 - 2016 Chevrolet Silverado/GMC Sierra with 6.6L Duramax diesel
6.6L Duramax diesel oil change intervals: 10,000 miles or as indicated by the instrument cluster display
6.6L Duramax oil filter: ACDelco PF2232
6.6L Duramax engine oil pan drain plug: GM 11569943
6.6L Duramax engine oil viscosity spec: See chart below for full breakdown
Duramax Engine Oil Selection
There is no reason nor excuse not to use a full synthetic motor oil. Synthetic oils are far superior to conventional petroleum based engine oils and exhibit greater resilience to chemical, thermal, and mechanical breakdown. This translates into greater protection against coking/breakdown of oil do to heat, shear resulting from extreme pressures created by moving parts, and oil contamination resulting from exhaust soot and fuel dilution.
We highly recommend Amsoil's line of full synthetic, diesel specific engine oils for all Duramax diesels. For more information on Amsoil's synthetic engine oil, see: Amsoil Signature Series Max-duty diesel oil (top tier product line) and/or Amsoil Heavy Duty diesel oil (up to 4 times greater wear protection than considered acceptable by current standards).
Duramax Engine Oil Viscosity Chart
Engine Oil Viscosity
Ambient temperature > 0° F (preferred viscosity within temp range)
Ambient temperature < 0° F (acceptable for all temps, required if temperature < 0° F)
Listed as acceptable for certain model years - not preferred nor advised under any conditions
Note that an SAE 15W-40 motor oil is recommended for all vehicles operating in ambient temperatures greater than 0° F, and SAE 5W-40 is required when operating in temperatures lower than 0° F. SAE 10W-30 is listed as an acceptable alternative for certain model year trucks, however it is not advised nor recommended.
6.6L Duramax Diesel Oil Change Procedures
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• 10 quarts of engine oil and a new oil filter are needed to perform an oil change. We also recommend changing the drain plug every few oil changes as the seal tends to degrade with age. At < $10, this is cheap insurance against preventable oil leaks.
We highly recommend Amsoil Heavy Duty 15W-40 full synthetic engine oil for all Duramax diesel applications, or Amsoil Heavy Duty 5W-40 full synthetic engine oil for cold weather operation.
• Place a suitable container (minimum 10 quarts capacity) beneath the engine oil pan.
• If applicable, place a shop rag between the oil pan and skid pan to prevent spillage; engine oil will have a tendency to pool here and run off one of the corners, evading your drain pan.
• Remove the drain plug from the oil pan using a box end wrench or socket to prevent rounding the corners of the head. Do not break the drain plug loose using an open end wrench. Drain plug head sizes will vary. In our case, the original required a 16 mm socket/wrench while the GM replacement had a 13 mm head.
• Once the engine oil has drained from the oil pan, clean and/or replace the drain plug. If the seal is compromised, replace the drain plug o-ring or install a new drain plug.
• Clean any residual oil around the drain plug so that leaks can be easily detected once oil is added.
• Remove the oil filter (located to the left of the engine above the front driveshaft on 4 wheel drive trucks) by unscrewing it from its mount. If the filter is stubborn, use an oil filter wrench or wrap a piece of sandpaper around the circumference of the filter to prevent your hand from slipping.
• Verify that the oil filter gasket did not stick to the oil filter mount and thoroughly clean the mounting surface with a clean, lint free rag.
• Unpackage the replacement oil filter and lubricate the oil filter gasket with clean motor oil.
• Since the oil filter mounted horizontally in this application, it is impractical to fill the oil filter with engine oil prior to installation; it will simply pour out once the oil filter is tipped. However, if desired, you may "wet" the filter with clean motor oil so it is not entirely dry when installed.
• Install the replacement oil filter hand tight. Do not use a wrench to tighten down the new filter, simply install it as tight as possible by hand. If the canister is slick, use a piece of sandpaper wrapped around the circumference to gain traction.
• Add 10 quarts of new engine oil through the oil fill tube located at the front, center of the engine compartment.
• Verify the oil level using the engine oil dipstick located on the passenger side of the engine (in front of the fuel filter housing).
• Start the engine and check for leaks around the oil pan drain plug and oil filter housing.