Why It's Difficult to Find a Specific Number:
* Engine Variations: Toyota Tercels came with several variations of the 1.5L engine. The specific oil weight may vary slightly between these versions.
* Climate: Recommended oil weights are often influenced by the climate where you live. Thicker oils are generally used in colder climates, while thinner oils are used in hotter climates.
* Older Car Data: Information for older vehicles can be harder to find online.
How to Determine the Correct Oil Weight:
1. Check Your Owner's Manual: This is the most reliable source. Look for a section on engine oil specifications. It will list the recommended oil weight and other important information.
2. Toyota's Website: While Toyota doesn't always have specific guides for older models, you can search their website for service information or contact customer support.
3. Consult a Mechanic: A trusted mechanic can look up the specific specifications for your Tercel and advise you on the appropriate oil weight.
4. Use a General Guideline: For a 1991 Tercel, a common general recommendation is 10W-30. However, this is NOT a guaranteed solution.
Important Considerations:
* Viscosity: The weight (e.g., 10W-30) refers to the viscosity of the oil. Viscosity is the oil's resistance to flow.
* Synthetic vs. Conventional: Synthetic oils are generally better at resisting breakdown and providing lubrication in a wider range of temperatures. You can use synthetic oil in your Tercel, but always check the owner's manual for compatibility.
It's Crucial to Use the Right Oil: Using the wrong oil weight can negatively impact your engine's performance and lifespan.
I hope this helps! Good luck in finding the right oil for your 1991 Tercel!
