However, generally speaking, for a 1991 Jeep Cherokee, you should use:
* SAE 10W-30: This is a common and generally suitable viscosity grade for most older engines, especially if you live in a moderate climate. It offers good protection across a range of temperatures.
* SAE 20W-50: If you live in a very hot climate, or if your engine is showing signs of wear (higher oil consumption), a thicker oil like 20W-50 might be considered. However, 10W-30 is usually preferred for older engines.
Crucially, you also need to consider the oil type:
* Conventional Oil: This is the most economical option. It's perfectly acceptable for your Cherokee if you change the oil regularly.
* High-Mileage Oil: Specifically formulated for older engines with more miles, high-mileage oils often contain additives to help with sealing and reduce leaks. Given the age of your vehicle, this might be a good choice.
* Synthetic Blend Oil: A good compromise between price and performance. It offers better protection than conventional oil.
* Full Synthetic Oil: The best protection, but also the most expensive. While it offers superior performance, the cost benefit may not outweigh the advantages for an older vehicle like a 1991 Cherokee unless it's highly modified.
Before buying oil, always check your owner's manual for the manufacturer's specific recommendations. This will ensure you're using the correct oil type and viscosity for your engine. Using the incorrect oil can damage your engine.
