{"id":522,"date":"2026-06-18T03:29:30","date_gmt":"2026-06-18T07:29:30","guid":{"rendered":"https:\/\/www.worldsbestdieseloil.com\/oil-guide\/2018-gmc-sierra-3500-pickup-6-6l-8-cyl-diesel-turbo-maintenance-guide\/"},"modified":"2026-06-18T03:29:30","modified_gmt":"2026-06-18T07:29:30","slug":"2018-gmc-sierra-3500-pickup-6-6l-8-cyl-diesel-turbo-maintenance-guide","status":"publish","type":"post","link":"https:\/\/www.worldsbestdieseloil.com\/oil-guide\/2018-gmc-sierra-3500-pickup-6-6l-8-cyl-diesel-turbo-maintenance-guide\/","title":{"rendered":"2018 GMC Sierra 3500 6.6L L5P Diesel Oil & Maintenance Guide"},"content":{"rendered":"
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\"AMSOIL
AMSOIL diesel oil guide for trucks, vans, SUVs and diesel engines<\/figcaption><\/figure>\n

For the 2018 GMC Sierra 3500 Pickup with the 6.6L 8-cylinder L5P Diesel Turbo engine, the oil capacity is 10 quarts<\/strong> (including filter replacement). The preferred viscosity for temperatures above -18\u00b0C is SAE 15W-40<\/strong>, though 5W-40<\/strong> is recommended for all temperatures when ambient conditions are below 0\u00b0F (-18\u00b0C) to improve cold starting. AMSOIL recommends the Signature Series 15W-40 Max-Duty Diesel Oil<\/a> paired with an AMSOIL oil filter<\/a> for optimal protection.<\/p>\n

What oil does a 2018 GMC Sierra 3500 6.6L L5P take?<\/h2>\n

The 2018 GMC Sierra 3500 with the 6.6L Duramax diesel engine requires an oil grade of CJ-4. For most operating conditions where temperatures remain above -18\u00b0C (0\u00b0F), SAE 15W-40 is the preferred viscosity. In extreme cold, a 5W-40 viscosity is recommended to facilitate easier engine starts.<\/p>\n

The total oil capacity for the 6.6L L5P engine is 10 quarts when performing a service that includes replacing the oil filter. It is essential to check the oil level after refilling to ensure accuracy.<\/p>\n

AMSOIL product recommendations<\/h2>\n

Based on the AMSOIL lookup for your 2018 GMC Sierra 3500, the following high-performance fluids and filters are recommended to maintain engine health and performance.<\/p>\n

Engine Oil Options<\/h3>\n
\n\n\n\n\n
Product Name<\/th>\nViscosity<\/th>\nCode<\/th>\n<\/tr>\n
Signature Series Max-Duty Diesel Oil<\/a><\/td>\n15W-40<\/a><\/td>\nDMEQT-EA<\/a><\/td>\n<\/tr>\n
Heavy-Duty Synthetic Diesel Oil<\/a><\/td>\n15W-40<\/a><\/td>\nADPQT-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Note: The AMSOIL lookup lists 5W-40 for use in all temperatures, specifically to improve cold starting when ambient temperatures are below 0\u00b0F (-18\u00b0C).<\/em><\/p>\n

Oil Filter Options<\/h3>\n
\n\n\n\n\n\n
Product Name<\/th>\nCode<\/th>\n<\/tr>\n
AMSOIL Oil Filter<\/a><\/td>\nEAO52-EA<\/a><\/td>\n<\/tr>\n
WIX XP Oil Filter<\/a><\/td>\n57202XP-EA<\/a><\/td>\n<\/tr>\n
WIX Oil Filter<\/a><\/td>\n57202-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Air & Coolant Recommendations<\/h3>\n
\n\n\n\n\n\n
Component<\/th>\nProduct Name<\/th>\nCode<\/th>\n<\/tr>\n
Air Filter<\/td>\nWIX Air Filter<\/a><\/td>\nWA10695-EA<\/a><\/td>\n<\/tr>\n
Coolant<\/td>\nPassenger Car & Light Truck Antifreeze<\/a><\/td>\nANTPC1G-EA<\/a><\/td>\n<\/tr>\n
Coolant (Conc.)<\/td>\nPropylene Glycol Antifreeze<\/a><\/td>\nANT1G-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Engine Oil Specifications<\/h3>\n
\n\n\n\n\n\n
Specification<\/th>\nDetails<\/th>\n<\/tr>\n
Oil Grade<\/td>\nCJ-4<\/td>\n<\/tr>\n
Preferred Viscosity<\/td>\n15W-40 (Above -18\u00b0C)<\/td>\n<\/tr>\n
Cold Weather Viscosity<\/td>\n5W-40 (All Temps)<\/td>\n<\/tr>\n<\/table>\n<\/div>\n

How much oil does it take with a filter change?<\/h2>\n

Service Specifications<\/h3>\n
\n\n\n\n\n
Metric<\/th>\nValue<\/th>\n<\/tr>\n
Oil Capacity<\/td>\n10 quarts (with filter)<\/td>\n<\/tr>\n
Oil Drain Plug Torque<\/td>\n18 ft\/lbs<\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Diesel maintenance notes for this vehicle<\/h2>\n

Maintaining a Duramax L5P engine requires attention to high-stress diesel combustion factors. Key areas of focus include:<\/p>\n