I have a 98 F-150 106k with an knocking noise from what I can assess is coming from the front of the engine. The noise can be soft, non-existant, or loud. Depending on how it feels I guess. It isn't consistant when the knock occurs. Hot or cold...it can start up making noise or not. It seems that if you put a load on it, it will make itself more noticeable. Performance is good and I am not using any oil. I took it to the dealer and had the service manager look at it and he thinks it might me the harmonic balance going soft. At least that is where he told me the noise was most prominant. He told me to take the truck home and remove the drive belt and check for play. Which I did..I couldn't get any movement by hand and there really isn't any place you can pry against that I would feel comfortable with. I started the engine without the belt in place and the noise went away completely...very smooth and sounded like it should with and without a load. After putting the belt back on tho..the noise returned...Is this kind of knocking noise common with the harmonic balance or are there other bolt on components I should be looking at as well...Standing in front of the engine the noise is pretty well drowned out, but if you stand next the the passenger door, you can hear it very well when It is at its loudest. Is this a common thing with the harmonic balance or should I be looking elsewhere?
Thanks