。
You can use my car whenever you want.
Literal
I [of-の] car [topic-は] any-time use good [emphasis-よ].
Note the casual particle drop — 'の車' has no を marking as direct object because it's elevated to topic-like status with ellipsis of the topic marker. いつでも ('any time, whenever') is the generic temporal indefinite. The pattern ~ていい ('it's okay to [verb], you may [verb]') is the standard casual permission-granting construction.