I know this is an old post but it may help someone else. You don't need dye just a blacklight. Look for coolant leaks along where the fan housing meets the radiator core. Mine rubbed a hole in the radiator there.Zoom in on this picture and you'll see what I'm talking about. It took me several months to locate the leak. Eventually it got large enough for me to find. I never thought about using a black light until then
. I tried the blacklight and it showed all of the antifreeze on the radiator.