New to me 1991. What type of oil is recommended.

 

Toyota recommends 10W-30. In 1991, conventional oil was the common type.

Where climate do you have in terms of high/low temps? What kind of driving do you do and how many miles per year?

Synthetic will always be the better oil choice. However it does cost more.

One advantage of synthetic is its available in lower viscosity ranges such as 5W-30. The lower viscosity helps with oil flow at cold starts.

The oil is operate better at higher temps. It does not break down as fast with use. That's one reason for the longer oil changes now recommended by car makers.

 

Thanks. I am in the high desert. Don't let that description fool you. We get snow here as well as sub zero temps. In the 90's in the Summer. Likely 10 to 15 k per year.

 

If you can afford the extra cost. Use a synthetic 5W-40 oil. This is good for -22 to 122F. Its better oil.

If going conventional oil use a 10W-40. -13 to 122F.