I'm running one side of the E3D Chimera+ with the standard E3D water cooling set, i.e. pump and radiator, with a BeQuiet 80x80x25 Pure Wings 2 fan at the radiator.
I did a comparison between air and water cooling with about 30°C room temperature, 250°C hotend tempereature and with the hotend above the middle of an 105°C heatbed. The air arount the print head was about 40 to 50°C.
Air cooled it was 50°C inside the second heatbreak bore.
Water coolded it was 32°C.
There is a blog post in german, but with some pictures also: https://drucktipps3d.de/wasserkuehlung-von-e3d/