yah a good amount of degreaser was necessary to find it on a few of the engines i had that had valve cover gasket leaks which had laid down years of grime, but it was there sure enough after about a half pound of black oil and dirt, ive had complete spider webs around my transmission even after driving the car for 3 months that never got cleaned off with the radiator fan blowing so.... its good to get in there and clean up every so often