For the 1981 Buick LeSabre equipped with the 5.7L 8-cylinder Diesel engine (Engine Code N), the oil capacity is 7 quarts with a filter change. 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 and the AMSOIL Oil Filter (EAO64-EA).
What oil does a 1981 Buick LeSabre 5.7L Diesel take?
The 1981 Buick LeSabre 5.7L diesel requires an oil grade of CF. The specific viscosity depends on your operating environment: 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
Based on the vehicle specifications, AMSOIL provides several high-performance lubrication options to maintain this vintage diesel engine. Below are the recommended products for your maintenance needs.
Engine Oil & Filter Kits
| Product Name | Code |
|---|---|
| Signature Series 5W-30 Max-Duty Diesel Oil | DHDQT-EA |
| Signature Series 10W-30 Max-Duty Diesel Oil | DTTQT-EA |
| Heavy-Duty 10W-30 Synthetic Diesel Oil | ADNQT-EA |
| AMSOIL Oil Filter | EAO64-EA |
Other Essential Fluids
| Component | AMSOIL Product & Code |
|---|---|
| Antifreeze/Coolant | Passenger Car & Light Truck Antifreeze (ANTPC1G-EA) |
| Antifreeze (Concentrate) | Propylene Glycol Antifreeze (ANT1G-EA) |
| Automatic Transmission Fluid | Signature Series ATF (ATLPK-EA) |
| Automatic Transmission Fluid | OE Fuel-Efficient ATF (OTLQT-EA) |
Engine Oil Specifications
| Viscosity | Condition/Note |
|---|---|
| 10W-30 | Below 16°C |
| 15W-40 | -18 to 16°C |
| 30 | Above 0°C (Preferred for continuous driving) |
Oil Grade: CF
Engine Oil Capacity & Torque
| Description | Value |
|---|---|
| Capacity (with filter) | 7 quarts |
| Oil Drain Plug Torque | 30 ft/lbs |
Note: Always check the oil level after refilling.
How much oil does it take with a filter change?
For a complete service including the replacement of the oil filter, this 5.7L diesel engine requires 7 quarts of oil. It is critical to verify the oil level using the dipstick after the refill to ensure accuracy.
Automatic Transmission Fluid Specifications
The transmission requirements vary based on your specific model (THM350C, THM200-4R, THM200C, or THM250C). Note that manufacturer technical service bulletins have updated the specification from Dexron II or III to Dexron VI for these applications.
Transmission Capacity Guide
| Transmission Type | Total Fill | Initial Fill |
|---|---|---|
| 3-speed THM350C | 10 quarts | 3 quarts |
| 4-speed THM200-4R | 11 quarts | 5 quarts |
| 3-speed THM200C | 9.4 quarts | 3.5 quarts |
| 3-speed THM250C | 10.8 quarts | 4 quarts |
Coolant Specifications & Capacity
Maintaining the cooling system is vital for diesel engine efficiency and longevity. The capacity depends on whether the vehicle is equipped with Air Conditioning (AC).
| Configuration | Capacity |
|---|---|
| With AC | 18 quarts |
| Without AC (O) | 18.5 quarts |
Diesel maintenance notes for this vehicle
Owners of vintage diesel engines like the 5.7L Engine Code N should prioritize several key areas to ensure reliability:
- Fuel System Integrity: Diesel engines from this era require careful monitoring of fuel injection components and fuel filter cleanliness.
- Cooling Efficiency: Ensure the cooling system is free of contaminants to manage the high thermal requirements of diesel combustion.
- Oil Viscosity: Always select the correct viscosity based on ambient temperature to ensure proper lubrication during startup and continuous operation.
Common diesel oil-related concerns and how AMSOIL products may help
| Concern | Why it matters | AMSOIL Product | How it may help | Limitation |
|---|---|---|---|---|
| Engine Wear | Diesel engines face high pressure and friction. | Signature Series 10W-30 | Delivers up to 6X more wear protection. | Requires regular oil changes. |
| Contaminants | Small particles can cause abrasive wear. | AMSOIL Oil Filter | 99% efficiency at 20 microns. | Filter must be replaced per interval. |
| Extreme Temperatures | Viscosity changes can affect lubrication. | Signature Series 5W-30 | Excels in extreme temperatures. | Not a substitute for correct grade selection. |
Common maintenance concerns for this vehicle
Based on historical context, owners of these vehicles should consider the following:
- Fuel Injection Reliability: Researching the reliability of fuel injection components is recommended for vintage diesel models.
- Glow Plug Operation: Proper operation of glow plugs is essential for reliable starting in older diesel architectures.
- Coolant System Maintenance: Ensuring compatibility with all cooling system metals, gaskets, and hoses is critical to prevent leaks or corrosion.
Recall, TSB, and manufacturer communication notes
Official NHTSA recall research for the 1981 Buick LeSabre identified the following:
- Brake Pedal Support Bracket: A recall (Campaign 80V125000) noted that some diesel-specific brackets might cause brakes to remain partially applied, leading to overheating.
- Accelerator Pump Pin: A recall (Campaign 83V077000) addressed a pin that could loosen, potentially causing the throttle to stick open.
- Brake Vacuum Hoses: A recall (Campaign 81V037000) noted that power brake vacuum hoses might not meet federal safety standards.
Disclaimer: Always verify current open recalls by checking your specific VIN through official manufacturer or NHTSA channels.
About this vehicle
The 1981 Buick LeSabre represents a significant era in General Motors’ history, positioned as a premium division between mainstream Chevrolet and luxury Cadillac. As a full-size offering, the LeSabre was designed to provide a balance of comfort and utility, commonly available in sedan and station wagon body styles.
This specific model is powered by a 5.7L 8-cylinder diesel engine (Engine Code N). Diesel engines from this era often require distinct maintenance considerations compared to gasoline counterparts, particularly regarding fuel system integrity, glow plug operation, and cooling system efficiency. Owners of these vintage diesel Buicks should focus on the reliability of fuel injection components and the specific requirements for heavy-duty engine oils suitable for older diesel architectures.
Because technical details like exact horsepower or torque ratings can vary, it is recommended to consult specialized service manuals for granular mechanical specifications. Maintenance should always distinguish between gasoline and diesel requirements to ensure compatibility with the engine’s compression ratios and thermal needs.
Common questions about this vehicle’s diesel oil and maintenance
What is the oil capacity for my 1981 Buick LeSabre Diesel?
The capacity is 7 quarts when replacing the filter. Always check the level after refilling.
Which AMSOIL oil is best for high-duty diesel use in this vehicle?
AMSOIL Signature Series 10W-30 (DTTQT-EA) is designed for outstanding extreme-pressure protection and wear resistance.
What should I use for my automatic transmission?
The AMSOIL lookup lists Signature Series ATF (ATLPK-EA) for these applications, noting that specifications have been updated to Dexron VI.
How often should I change my coolant?
While specific intervals aren’t listed, AMSOIL products like the Passenger Car & Light Truck Antifreeze provide protection for up to 150,000 miles or 5 years.
Does this vehicle have any known recalls?
Yes, NHTSA records indicate recalls related to brake pedal support brackets, accelerator pump pins, and vacuum hoses. Verify your VIN with a dealer.
What is the torque spec for the oil drain plug?
The confirmed torque for the oil drain plug is 30 ft/lbs.
Disclaimer: This information is derived from provided source data. Always consult your owner’s manual and verify all specifications before performing vehicle maintenance.