That information is in your owners manual and probably on the engine oil cap. The recommended viscosity for the Solara is 5W-40 for all operating temperatures. If you only drive within a temperature range of -20 to 104 degrees F you can use 10W-30 and if you drive in -30 to mid 80 degree F temperatures your manual recommends 5W-30. If you're asking about oil brand/type you may find this test informative: http://jcpm-inc.com/images/oiltest.pdf Anytime you poll a group of drivers you'll find most have their favorite brand. Choose based on your own driving habits/needs and depth of pocketbook. Cheers
dexron III
Genuine Toyota ATF T-IV, which is fully synthetic
The 2003 Toyota RAV4 has double overhead cam (DOHC).
The 2003 Toyota Sienna has double overhead cam (DOHC).
The 2003 Toyota Avalon has double overhead cam (DOHC).
The 2003 Toyota Sequoia has double overhead cam (DOHC).
The 2003 Toyota Tundra has double overhead cam (DOHC).
The 2003 Toyota Highlander has double overhead cam (DOHC).
The 2003 Toyota Tacoma has double overhead cam (DOHC).
The 2003 Toyota 4Runner has double overhead cam (DOHC).
The 2003 Toyota Camry has double overhead cam (DOHC).
The 2003 Toyota Matrix has double overhead cam (DOHC).