However, assuming it's a gasoline engine, conventional oil with a viscosity of 10W-30 or 20W-40 was commonly recommended for that era. Always refer to your owner's manual for the manufacturer's specific recommendation. If you don't have the manual, you can often find a digital version online by searching for your truck's specific year, make, model, and engine.
Important considerations:
* Engine size and type: Different engines have different oil requirements. The engine size (e.g., 302, 351, etc.) will significantly impact the recommendation.
* Climate: Thicker oils (like 20W-40) are better for hotter climates, while thinner oils (like 10W-30) are better for colder climates.
* Oil type: While conventional oil was standard in 1984, you *could* use a higher-quality oil like synthetic blend or full synthetic. However, there's no real benefit unless the engine is significantly worn or you plan on extended oil change intervals. Using a higher-quality oil than recommended isn't harmful, though.
In short: Start by identifying your engine. Then, check your owner's manual or consult an online resource for that specific engine's oil recommendations. If all else fails, a local auto parts store can assist based on your truck's details.
