For the 1986 Chevrolet Blazer with the 6.2L 8-cylinder Diesel engine (Engine Code C), the oil capacity is 7 quarts when performing a change with a filter. The preferred viscosity for temperatures above -18°C is SAE 10W-30. AMSOIL recommends using Signature Series 10W-30 100% Synthetic Max-Duty Diesel Oil (DTTQT-EA) or the Heavy-Duty 100% Synthetic Diesel Oil (ADNQT-EA) for optimal protection.
What oil does a 1986 Chevrolet Blazer 6.2L Diesel take?
The 1986 Chevrolet Blazer with the 6.2L 8-cylinder diesel engine requires an oil grade of CF-4. Depending on your ambient operating temperatures, different viscosities are recommended to ensure proper lubrication and protection.
The engine oil capacity is 7 quarts when replacing the filter. It is important to check the oil level after refilling.
AMSOIL product recommendations
Based on the AMSOIL lookup data, here are the recommended fluids and filters for your 1986 Chevrolet Blazer 6.2L Diesel.
Engine Oil Options
| Product Name | Code |
|---|---|
| AMSOIL Signature Series 10W-30 Max-Duty Diesel Oil | DTTQT-EA |
| AMSOIL 10W-30 Heavy-Duty Synthetic Diesel Oil | ADNQT-EA |
| AMSOIL Signature Series 5W-30 Max-Duty Diesel Oil | DHDQT-EA |
Oil Filter Options
Coolant & Transmission Fluids
| Component | Product Name | Code |
|---|---|---|
| Coolant | AMSOIL Passenger Car & Light Truck Antifreeze | ANTPC1G-EA |
| Coolant | AMSOIL Propylene Glycol Antifreeze | ANT1G-EA |
| ATF (THM400) | AMSOIL Signature Series Fuel-Efficient ATF | ATLPK-EA |
| ATF (THM400) | AMSOIL OE Fuel-Efficient ATF | OTLQT-EA |
| ATF (THM700-R4) | AMSOIL Signature Series Fuel-Efficient ATF | ATLPK-EA |
Engine Oil Viscosity Guide
| Temperature Range | Recommended Viscosity |
|---|---|
| Below 16°C | 5W-30 |
| Above -18°C | 10W-30 (Preferred) |
| Above -12°C | 15W-40 |
| Above -7°C | 20W-20 |
| Above 4°C | 30 |
Engine Oil Capacity
How much transmission fluid does it take?
Capacity varies significantly depending on which automatic transmission is installed in your Blazer. Always verify your specific model before filling.
Transmission Capacity Details
| Transmission Type | Total Fill Capacity | Initial Fill Capacity |
|---|---|---|
| 3-speed THM400 | 10.6 quarts | 4.3 quarts |
| 4-speed THM700-R4 | 11.5 quarts | 5 quarts |
Note: For both transmissions, the manufacturer’s technical service bulletin has updated the specification from Dexron II or III to Dexron VI.
Coolant Specifications and Capacity
Maintaining proper cooling efficiency is vital for diesel longevity. The capacity depends on whether your vehicle is equipped with Air Conditioning (AC).
| Configuration | Capacity |
|---|---|
| With AC | 18 quarts |
| Without AC (O) | 17.4 quarts |
Common diesel oil-related concerns and how AMSOIL products may help
Diesel engines face unique stresses such as soot loading and high heat. The following table outlines how specific AMSOIL products can support your maintenance needs.
| Concern | Why it matters | AMSOIL Product | How it may help | Limitation |
|---|---|---|---|---|
| Engine Wear | Diesel combustion creates high pressure and friction. | DTTQT-EA | Delivers up to 6X more wear protection. | Requires regular oil changes. |
| Contaminants | Small particles can cause abrasive wear. | EAO24-EA | 99% efficiency at 20 microns. | Filter must be replaced per interval. |
| Extreme Temperatures | Viscosity changes can affect lubrication during startup or heavy load. | DHDQT-EA | Excels in extreme temperatures. | Not a substitute for proper viscosity selection. |
Diesel maintenance notes for this vehicle
- Oil Level Check: Always check the oil level after refilling to ensure you have not overfilled or underfilled the engine.
- Filter Efficiency: Using a high-efficiency filter like the AMSOIL Oil Filter (EAO24-EA) can help provide greater capacity for small, wear-causing contaminants.
- Coolant Mixing: If using AMSOIL Propylene Glycol Antifreeze (ANT1G-EA), remember it is concentrated and requires mixing with distilled or high-quality water.
Recall, TSB, and manufacturer communication notes
NHTSA research indicates the following for the 1986 Chevrolet Blazer:
Recalls
- Exterior Lighting: A recall (Campaign 06E026000) was noted regarding certain replacement lamps that may fail to conform to safety standards, potentially resulting in poor illumination.
- Oil Filter Gasket: A recall (Campaign 07E088000) involved certain FRAM Racing HP4 and HP8 oil filters where the gasket could become too pliable under high temperature/pressure, potentially causing oil loss or fire risk.
Disclaimer: Always verify open recalls by using your specific VIN through official manufacturer channels or the NHTSA website.
NHTSA Complaint Patterns
NHTSA consumer complaints for this model year include reports related to:
- Engine and Engine Cooling (4 reports)
- Tires (3 reports)
- Service Brakes (2 reports)
- Steering (2 reports)
Note: NHTSA complaints are owner reports and should not be treated as verified defects.
About this vehicle
The 1986 Chevrolet Blazer equipped with the 6.2L 8-cylinder diesel engine is a classic representative of General Motors’ heavy-duty utility offerings from the mid-1980s. While modern enthusiasts may associate the “Duramax” name with newer GM diesel technology, this 6.2L engine belongs to an earlier era of mechanical diesel engineering that was highly regarded for its durability and torque in trucks and SUVs.
Based on historical context, this vehicle is likely part of the full-size lineage (such as the K5 Blazer) rather than the compact S-series, given the displacement of the 6.2L engine. These vehicles were commonly used for towing and utility work, making them subject to significant mechanical stress.
Maintenance for these vintage diesels often focuses on mechanical oversight of injection pumps, glow plug systems, and maintaining cooling efficiency. Because this engine predates modern electronic common-rail systems, owners typically prioritize fuel system integrity and robust lubrication to manage the mechanical components characteristic of mid-80s diesel technology.
Maintenance Note: All fluid recommendations should be verified via an official service manual or OEM specifications before performing maintenance.
Common questions about this vehicle’s diesel oil and maintenance
What is the preferred oil viscosity for my 1986 Blazer 6.2L Diesel?
The AMSOIL lookup prefers SAE 10W-30 for temperatures above -18°C.
How much oil does the 6.2L engine take with a filter change?
It takes 7 quarts including the filter replacement.
Can I use synthetic oil in my 1986 diesel?
Yes, AMSOIL offers options like the Signature Series 10W-30 (DTTQT-EA) which is designed for max-duty diesel applications.
What should I do if my transmission is a THM400?
For the 3-speed THM400, the total fill capacity is 10.6 quarts. The AMSOIL lookup references an update from Dexron II/III to Dexron VI for this application.
Does my diesel need a special filter?
While any suitable filter works, the AMSOIL Oil Filter (EAO24-EA) is designed to provide 99% efficiency at 20 microns.
How do I verify if there are active recalls on my Blazer?
You should contact a Chevrolet dealer or use your VIN on the official NHTSA website to check for any outstanding manufacturer recalls.
Disclaimer: Information provided is based on available source data. Always consult an official service manual and verify all specifications before performing vehicle maintenance.