If you are doing it yourself I would go with the warm, also get some of the "degreaser" I see it at home depot, lowes one of the brands is a citrus mixture, another is purple power or something like that. Mix up a strong mixture of it and once you shut your engine off mist everything with a spray bottle use a lot of the stuff and leave it sit for 15-20 min, then when you spray it off won't have to spend as much time shooting water at your engine.