{"id":483,"date":"2026-06-15T08:56:34","date_gmt":"2026-06-15T12:56:34","guid":{"rendered":"https:\/\/www.worldsbestdieseloil.com\/oil-guide\/1985-buick-riviera-5-7l-8-cyl-diesel-maintenance-guide\/"},"modified":"2026-06-15T08:56:34","modified_gmt":"2026-06-15T12:56:34","slug":"1985-buick-riviera-5-7l-8-cyl-diesel-maintenance-guide","status":"publish","type":"post","link":"https:\/\/www.worldsbestdieseloil.com\/oil-guide\/1985-buick-riviera-5-7l-8-cyl-diesel-maintenance-guide\/","title":{"rendered":"1985 Buick Riviera 5.7L Diesel Maintenance Guide: Oil & Fluid Specs"},"content":{"rendered":"
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\"AMSOIL
AMSOIL diesel oil guide for trucks, vans, SUVs and diesel engines<\/figcaption><\/figure>\n

For the 1985 Buick Riviera with the 5.7L 8-cylinder Diesel engine (Code N), the oil capacity is 7 quarts with a filter change. Recommended viscosities include 10W-30 for temperatures below 16\u00b0C, 15W-40 for -18 to 16\u00b0C, and 30 weight for continuous driving above 0\u00b0C. AMSOIL recommends using Signature Series 10W-30 Max-Duty Diesel Oil<\/a> (DTTQT-EA<\/a>) paired with an AMSOIL Oil Filter<\/a> (EAO64-EA<\/a>).<\/p>\n

What oil does a 1985 Buick Riviera 5.7L Diesel take?<\/h2>\n

The engine requires an oil with a CF specification. Depending on your operating environment, the appropriate viscosity varies: use 10W-30 for temperatures below 16\u00b0C, 15W-40 for temperatures between -18 to 16\u00b0C, and 30 weight is preferred for continuous driving when temperatures are above 0\u00b0C.<\/p>\n

AMSOIL product recommendations<\/h2>\n

Based on the AMSOIL lookup for your 1985 Buick Riviera 5.7L Diesel, here are the recommended high-performance fluids and filters.<\/p>\n

Engine Oil & Filter Kits<\/h3>\n
\n\n\n\n\n\n\n
Product Name<\/th>\nCode<\/th>\n<\/tr>\n
Signature Series 10W-30 Max-Duty Diesel Oil<\/td>\nDTTQT-EA<\/a><\/td>\n<\/tr>\n
Signature Series 5W-30 Max-Duty Diesel Oil<\/td>\nDHDQT-EA<\/a><\/td>\n<\/tr>\n
Heavy-Duty 10W-30 Synthetic Diesel Oil<\/td>\nADNQT-EA<\/a><\/td>\n<\/tr>\n
AMSOIL Oil Filter<\/td>\nEAO64-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Other Essential Fluids<\/h3>\n
\n\n\n\n\n\n\n\n\n
Component<\/th>\nRecommended Product<\/th>\nCode<\/th>\n<\/tr>\n
Coolant<\/td>\nPassenger Car & Light Truck Antifreeze<\/td>\nANTPC1G-EA<\/a><\/td>\n<\/tr>\n
Coolant (Conc.)<\/td>\nPropylene Glycol Antifreeze<\/td>\nANT1G-EA<\/a><\/td>\n<\/tr>\n
Automatic Trans<\/td>\nSignature Series Fuel-Efficient ATF<\/td>\nATLPK-EA<\/a><\/td>\n<\/tr>\n
Automatic Trans<\/td>\nOE Fuel-Efficient ATF<\/td>\nOTLQT-EA<\/a><\/td>\n<\/tr>\n
Front Differential<\/td>\nSevere Gear 80W-90 Synthetic<\/a><\/td>\nAGLPK-EA<\/a><\/td>\n<\/tr>\n
Front Differential<\/td>\nSevere Gear 75W-90 Synthetic<\/a><\/td>\nSVGPK-EA<\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Engine Oil Specifications<\/h3>\n
\n\n\n\n\n\n
Viscosity<\/th>\nTemperature Range<\/th>\n<\/tr>\n
10W-30<\/td>\nBelow 16\u00b0C<\/td>\n<\/tr>\n
15W-40<\/td>\n-18 to 16\u00b0C<\/td>\n<\/tr>\n
30<\/td>\nAbove 0\u00b0C (Preferred for continuous driving)<\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Engine Oil Capacity & Torque<\/h3>\n
\n\n\n\n\n
Detail<\/th>\nSpecification<\/th>\n<\/tr>\n
Oil Capacity<\/td>\n7 quarts (with filter replacement)<\/td>\n<\/tr>\n
Drain Plug Torque<\/td>\n30 ft\/lbs<\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Note: Always check the oil level after refilling.<\/em><\/p>\n

Automatic Transmission Fluid Specifications<\/h2>\n

For the THM325-4L automatic transmission, the manufacturer’s technical service bulletin has updated the specification from Dexron II or III to Dexron VI. Ensure you use a fluid compatible with this update.<\/p>\n

Transmission Capacity<\/h3>\n
\n\n\n\n\n
Fill Type<\/th>\nCapacity<\/th>\n<\/tr>\n
Initial Fill<\/td>\n3.2 quarts (does not include differential)<\/td>\n<\/tr>\n
Total Fill (4-speed THM325-4L)<\/td>\n10 quarts<\/td>\n<\/tr>\n<\/table>\n<\/div>\n

Coolant and Differential Specifications<\/h2>\n

The cooling system requires 18 quarts of capacity. For the front differential, a GL-5 all-temps 80W-90 specification is noted with a capacity of 3.2 pints.<\/p>\n

Differential Lubricant<\/h3>\n
\n\n\n\n
Component<\/th>\nCapacity<\/th>\n<\/tr>\n
Front Differential<\/td>\n3.2 pints<\/td>\n<\/tr>\n<\/table>\n<\/div>\n

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

Maintaining a vintage diesel engine requires attention to specific subsystems. Based on the technical data, owners should prioritize:<\/p>\n