no silicone, as you push it on you will curl up those little blobs of rubber which will end up inside your engine. use a light oil, and heat it up. It should go on very easily, I've only had 3 or 4 of them off, but in each case my concern was it coming off rather than any problem putting them on. Even if you do end up pounding it on, keep in mind they have been doing it that way for about 70 years. Use a little common sense, if it isn't going don't just keep pounding, no really, it should go on pretty easily.
