Don't really need to, though usually after I fasten my seat belt, get my music selection all ready to go 20-30 seconds has passed. Sometimes I just start and go though, it doesn't really get that cold here for the idle to ever deviate from 650 RPM. Driving gently in gear is a better way to warm your engine up then idling in park will ever be anyway.

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1985 CA 300D Turbo , 213K mi