Gallert3

Hello, I'm struggling with making a interplanetary spaceship using FFT and SH. I built the ship in the VAB, then separated it to launch it. Now, I cannot get the engine and the radiators on the same cooling loop. (if i put the engine on loop 1, the radiators cannot use loop 1) I looked through here and the wiki, but couldn't find out what my problem is. Does anyone know how to solve this?