RETed is correct. You really need to use the proper gasket. Housings do break, have seen it. Problem with using a lot of rtv will be that excess will go to the inside and will usually fall off and will get into the cooling system usually ends up blocking off internal cooling holes in rotor housings, or thermostat. When it blocks the ports in the rotor housings it will cause overheating in that area eventually causing motor failure. Do not know how many overheated motors I have had come through here that were caused by someone using RTV.