For the 1981 Buick Riviera with the 5.7L 8-cylinder Diesel engine (Engine Code N), the oil capacity is 7 quarts (including filter replacement). Recommended viscosities include 10W-30 for temperatures below 16°C, 15W-40 for -18 to 16°C, and 30 weight for continuous driving above 0°C. AMSOIL recommends using Signature Series 10W-30 Max-Duty Diesel Oil (DTTQT-EA) paired with an AMSOIL Oil Filter (EAO64-EA).
What oil does a 1981 Buick Riviera 5.7L Diesel take?
The 1981 Buick Riviera with the 5.7L 8-cylinder diesel engine requires an oil grade of CF. Viscosity selection should be based on ambient operating temperatures: use 10W-30 for temperatures below 16°C, 15W-40 for temperatures between -18 to 16°C, and a 30 weight oil is preferred for continuous driving when temperatures are above 0°C.
AMSOIL product recommendations
The following AMSOIL products are recommended for the 1981 Buick Riviera 5.7L Diesel to ensure optimal protection and performance.
Engine Oil Options
| Product Name | Viscosity | Code |
|---|---|---|
| AMSOIL Signature Series Max-Duty Diesel Oil | 10W-30 | DTTQT-EA |
| AMSOIL 10W-30 Heavy-Duty Synthetic Diesel Oil | 10W-30 | ADNQT-EA |
| AMSOIL Signature Series Max-Duty Diesel Oil | 5W-30 | DHDQT-EA |
Note: Oil Grade is CF.
Filtration & Coolant
| Component | Product Name | Code |
|---|---|---|
| Oil Filter | AMSOIL Oil Filter | EAO64-EA |
| Antifreeze | AMSOIL Passenger Car & Light Truck | ANTPC1G-EA |
| Antifreeze | AMSOIL Propylene Glycol | ANT1G-EA |
Transmission & Gear Lubricants
| Component | Product Name | Code |
|---|---|---|
| Automatic Trans Fluid | AMSOIL Signature Series Fuel-Efficient | ATLPK-EA |
| Automatic Trans Fluid | AMSOIL OE Fuel-Efficient | OTLQT-EA |
| Front Differential | AMSOIL SEVERE GEAR 80W-90 | AGLPK-EA |
| Front Differential | AMSOIL SEVERE GEAR 75W-90 | SVGPK-EA |
Engine Oil Specifications
| Specification | Details |
|---|---|
| Oil Grade | CF |
| Drain Plug Torque | 30 ft/lbs |
Oil Capacity Details
| Description | Capacity |
|---|---|
| Total Capacity (with filter) | 7 quarts |
Note: Always check the oil level after refilling.
How much oil does it take with a filter change?
A complete oil and filter service for this vehicle requires 7 quarts of oil. It is critical to verify the oil level manually after the refill process to ensure accuracy.
Automatic Transmission Fluid Specifications
For the automatic transmission (THM325), the AMSOIL lookup notes that the specification has been updated from Dexron II or III to Dexron VI per a manufacturer Technical Service Bulletin. The total fill capacity for the 3-speed THM325 is 12 quarts, while the initial fill capacity is 5 quarts (this does not include the differential).
Differential and Cooling System Data
Front Differential
The front differential requires GL-5 All TEMPS 80W-90 lubricant. The confirmed capacity for the front differential is 3.2 pints.
Cooling System
The cooling system has a total capacity of 18 quarts. AMSOIL offers both a 50/50 pre-mix ethylene glycol formulation and a concentrated propylene glycol option that requires mixing with distilled or high-quality water.
Common diesel oil-related concerns and how AMSOIL products may help
| Concern | Why it matters | AMSOIL product from this lookup | How it may help | Important limitation |
|---|---|---|---|---|
| Engine Wear | Diesel engines face high pressure and friction. | DTTQT-EA | Delivers up to 6X more wear protection. | Requires proper service intervals. |
| Contaminants | Small particles can cause internal damage. | EAO64-EA | 99% efficiency at 20 microns. | Filter must be replaced regularly. |
| Thermal Stress | High temperatures can degrade oil. | DTTQT-EA | Excels in extreme temperatures. | Not a substitute for cooling system repair. |
Diesel maintenance notes for this vehicle
- Fuel Quality: Owners of vintage diesel Buicks should prioritize strict adherence to fuel quality standards to prevent injector issues.
- Thermal Management: Proper cooling system maintenance is vital for these engines.
- Access Note: Due to the front-wheel-drive configuration, accessing certain engine components may differ from traditional rear-drive luxury cars.
Recall, TSB, and manufacturer communication notes
NHTSA recall research for the 1981 Buick Riviera identified one recall record:
Note: Always verify open recalls by VIN through an official dealer or the NHTSA website.
NHTSA complaint research returned no records for this specific year, make, and model combination. Please note that NHTSA complaints are owner reports and do not constitute confirmed defects.
About this vehicle
The 1981 Buick Riviera represents a significant era in General Motors’ history, marking a transition in the brand’s luxury offerings. This generation of Riviera was notable for its shift in architecture; unlike earlier iterations that utilized rear-wheel drive, models from the late 1970s onward moved to a front-wheel-drive configuration. This fundamental change altered both handling characteristics and maintenance access compared to previous generations.
Under the hood, this specific model is equipped with a 5.7L 8-cylinder diesel engine (Engine Code N). While Buick is widely recognized for its V6 engine families—such as the 3.8L 3800 series—this diesel V8 configuration represents a distinct mechanical lineage within the GM ecosystem. Because this vehicle belongs to a specific era of diesel technology, maintenance enthusiasts often focus on specialized care regarding fuel systems and thermal management.
Owners should be aware that because this is a front-wheel-drive layout, engine component access may differ significantly from traditional rear-drive luxury cars. Furthermore, researchers recommend verifying all technical specifications using a dedicated service manual or the vehicle’s physical identification plate, as specific requirements for diesel-specific lubricants and cooling additives are critical for long-term reliability.
Common questions about this vehicle’s diesel oil and maintenance
What is the oil capacity for my 1981 Buick Riviera Diesel?
The engine requires 7 quarts of oil when performing a service that includes a filter change.
Which AMSOIL oil is best for extreme temperatures?
AMSOIL Signature Series Max-Duty Diesel Oils (such as DTTQT-EA) are designed to excel in extreme temperatures and maintain proper viscosity.
What should I use for my automatic transmission?
The AMSOIL lookup lists Signature Series Fuel-Efficient ATF (ATLPK-EA) for this application, noting the manufacturer’s update to Dexron VI.
How often should I change my diesel oil?
While specific intervals depend on driving conditions, AMSOIL Signature Series products are designed to allow you to confidently extend drain intervals.
What is the torque spec for the oil drain plug?
The oil drain plug should be torqued to 30 ft/lbs.
Is there a recall for my 1981 Riviera?
NHTSA research indicates a recall regarding front left upper control arm nuts that may not have been securely tightened. Verify your specific VIN with a dealer.
Disclaimer: Not all information is confirmed from source data. Always verify specifications using a dedicated service manual or the vehicle’s physical identification plate before performing maintenance.