On taxi out to 22L departure from DTW, Palace 4, the one that goes north towards LAYNE/BNNET/DIRKS/LEATO towards Lake Michigan. Since we're taxiing to 22L, we're facing the direction of departure and there was some weather. So I turn the radar on, and range was lower, 20/10 mile. I open it up to 80/40 to take a look. I barely opened up that range when he snapped, 'It's good CRM to let the other pilot know when you change the radar range.' I mean I had just opened it up to the 80/40 range. I didn't even get a chance to explain what I was doing. Oh well. Inside I thought to myself that it's also good CRM not to be an ass, but hey, I'm just a lowly FO.