Toyota 2005 Sienna Owner's Manual page 475

Engine oil selection
"Toyota Genuine Motor Oil" is used in
your Toyota vehicle. Use Toyota approved
"Toyota Genuine Motor Oil" or equivalent
to satisfy the following grade
viscosity.
Oil grade:
API grade SL "Energy−Conserving" or
ILSAC multigrade engine oil
Recommended viscosity:
SAE 5W−30
Outside temperature
SAE 5W−30 is the best choice for good
fuel economy and good starting in cold
weather.
05 SIENNA_U (L/O 0409)
If SAE 5W−30 is not available, SAE
10W−30 may be used.
should be replaced with SAE 5W−30 at
the next oil change.
and
However, it
API service symbol
ILSAC certification mark
2005 SIENNA from Sep. '04 Prod. (OM45431U)
467