What kind of oil should I use when I do an oil change on my 1998 toyota Sienna v

The kind that is real slippery! Refer to the owners manual.. ALL that information is in there!

That vehicle calls for 5qts of a 5W30 or a 10W30 weight oil. Depending on the mileage or if it's burning significant oil in between changes (over 2 1/2 quarts) every 3000 miles. I'd run 10w30. If the consumption is not that high use the 5W30.