However, generally speaking, for a 1989 Ford Tempo, you'd likely want to use a SAE 10W-30 oil that meets the API (American Petroleum Institute) service classification SG, SH, SJ, or SL. Some may even recommend an oil meeting the newer SM or SN ratings, but sticking to the older recommendations (SG, SH, SJ, SL) is perfectly acceptable and often preferable for older engines.
Important Considerations:
* Owner's Manual: Check your owner's manual for the *exact* recommendation from Ford. This is the most reliable source.
* Oil Viscosity: The 10W-30 is a common suggestion for a balance of winter and summer performance, but again, check your manual. Different viscosities may be recommended depending on climate.
* API Rating: The API rating indicates the oil's performance characteristics. Using an oil with a newer API rating than recommended shouldn't hurt, but there's no significant benefit in this case. Sticking to the older, recommended ratings is fine.
* Oil Type: Use conventional, synthetic blend, or full synthetic oil as your preference and budget dictate. A conventional oil is usually sufficient for older engines, unless there are specific issues or preferences.
Without knowing the exact engine in your 1989 Ford Tempo, this is the best general advice. Always consult your owner's manual for the most accurate and reliable information.
