hello , was putting together a new build today but was taking my h80i from my old one and notice when i put my hands on the rubber caps a black residue would come off them . now this residue did not come of any other part of the tube nor did i see any near the radiator i think it may be just the rubber heating up so much that its coming off (it did smell exactly like rubber and was just plain black)but am not sure could anyone give me some advice on what this is just abit worried becaue its a new build and dont want a leak and what not thanks.