You DO have a timing belt. Read your owner's manual. Read the part about maintenance schedule. Also, read about the proper fluid specification section. You can extend the life of your timing belt by keeping your engine showroom clean (use power wash). Repair any oil leaks as they occur (watch once in a while). and by using ONLY Mobil One oil "designed for use in Toyots vehicles". Stay away from the big "V" and other regular dino based oils, they only decompose into varnish and sludge. WIth the Mobil One, you can change the oil every 1-2 years and save $$$$$. You will be doing your engine a favor, as well, by reducing friction, and prevernting oil seal leaks!!! If you have platinum plugs, only need changing every 80,000 miles. READ your MANUAL about SCHEDULE!!!!!!!! Good Luck!!