let bike cool down before washing???

Can you mess anything up by washing a bike that's up to temp? If I’ve been out riding I usually try to let the engine cool off for about 30 minutes before I wash it...sometimes I'll throw a shop fan on it to speed things up. Last time I washed mine there was steam coming off the cases and exhaust pretty good when I started spraying it down. I don't wanna crack the case or anything like that.