Why do old topics get locked? Simple. Our knowledge and experience change. What mechanical advice was dished out a year ago might not be valid today. We had alot of that going on for awhile, which is why we put that rule into place.
In addition, someone not really good at troubleshooting will see someone else'* old problem and just assume that their solution will be the same. This isn't always the case. We like to encourage a person to start a new topic with their OWN symptoms and observations for more valid troubleshooting.
Now go out there and find me a Forum with a more easygoing attitude (not including poetry forums) and we'll talk some more.