{"id":639,"date":"2026-06-26T18:40:21","date_gmt":"2026-06-26T22:40:21","guid":{"rendered":"https:\/\/www.worldsbestdieseloil.com\/oil-guide\/1998-gmc-suburban-6-5l-diesel-maintenance-guide\/"},"modified":"2026-06-26T18:40:21","modified_gmt":"2026-06-26T22:40:21","slug":"1998-gmc-suburban-6-5l-diesel-maintenance-guide","status":"publish","type":"post","link":"https:\/\/www.worldsbestdieseloil.com\/oil-guide\/1998-gmc-suburban-6-5l-diesel-maintenance-guide\/","title":{"rendered":"1998 GMC Suburban 6.5L Diesel Maintenance Guide: Oil, Filters & Fluids"},"content":{"rendered":"
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\"AMSOIL
AMSOIL diesel oil guide for trucks, vans, SUVs and diesel engines<\/figcaption><\/figure>\n

What oil does a 1998 GMC Suburban 6.5L Diesel take?<\/h2>\n

For the 1998 GMC Suburban with the 6.5L 8-cylinder L65 F Diesel Turbo engine, the recommended oil viscosity is 15W-40 (preferred for temperatures above -18\u00b0C) or 10W-30 (for temperatures below 0\u00b0C). The engine requires an oil capacity of 8 quarts with a filter change. AMSOIL recommends using Signature Series 15W-40 Max-Duty Diesel Oil<\/a> or Heavy-Duty 15W-40 Synthetic Diesel Oil<\/a>.<\/p>\n

AMSOIL product recommendations<\/h2>\n

Based on the vehicle lookup for the 6.5L L65 F Diesel Turbo, the following AMSOIL products are recommended for optimal performance and protection.<\/p>\n

Engine Oil Options<\/h3>\n
\n\n\n\n\n
Product Name<\/th>\nPart Code<\/th>\n<\/tr>\n
AMSOIL Signature Series 15W-40 100% Synthetic Max-Duty Diesel Oil<\/td>\nDMEQT-EA<\/a><\/td>\n<\/tr>\n
AMSOIL 15W-40 Heavy-Duty 100% Synthetic Diesel Oil<\/td>\nADPQT-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Oil Filter Options<\/h3>\n
\n\n\n\n\n
Product Name<\/th>\nPart Code<\/th>\n<\/tr>\n
AMSOIL Oil Filter<\/td>\nEAO24-EA<\/a><\/td>\n<\/tr>\n
WIX Oil Filter<\/td>\n51060-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Air Filter & Coolant<\/h3>\n
\n\n\n\n\n\n
Product Name<\/th>\nPart Code<\/th>\n<\/tr>\n
WIX Air Filter<\/td>\n46441-EA<\/a><\/td>\n<\/tr>\n
AMSOIL Passenger Car & Light Truck Antifreeze & Coolant<\/td>\nANTPC1G-EA<\/a><\/td>\n<\/tr>\n
AMSOIL Propylene Glycol Antifreeze and Engine Coolant<\/td>\nANT1G-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Automatic Transmission Fluid<\/h3>\n
\n\n\n\n
Product Name<\/th>\nPart Code<\/th>\n<\/tr>\n
AMSOIL Signature Series Fuel-Efficient 100% Synthetic ATF<\/td>\nATLPK-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n
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Engine Oil Specifications & Details<\/h2>\n

Maintaining the correct oil specification is vital for the longevity of the 6.5L diesel engine. The AMSOIL lookup notes indicate an oil grade of CG-4.<\/p>\n

Oil Viscosity Guide<\/h3>\n
\n\n\n\n\n\n
Temperature Range<\/th>\nRecommended Viscosity<\/th>\n<\/tr>\n
Below 0\u00b0C<\/td>\n10W-30<\/td>\n<\/tr>\n
Above -18\u00b0C<\/td>\n15W-40 (Preferred)<\/td>\n<\/tr>\n
Above 0\u00b0C<\/td>\n30<\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Oil Capacity & Service Data<\/h3>\n