Here is my take. From the day I bought my car 4 years ago I wondered about the loud noise. When I first got it, someone riding in my car even said "this thing is loud". Sometimes when I turn the car off I can hear a clunk clunk as the engine is winding down to a stop. While running I hear a ticking noise. Sometimes I hear it more when I first start the car. The noise may not be as bad as yours but it can't compare the two.

I brought it in to the dealership and they told me it was normal. 4 years later and 55K miles everything is still great! No engine problems.... I change the oil regularly and I bet I will get another 150K miles out of the engine! But it is still making noise. I work with some engineers and asked them 4 years ago. They purchased new cars that made strange noises and it worried them. They asked the dealership to fix it and said it was normal (just like me). They drove the cars 150K+ miles with no problems and sold the car still running. Years ago my dad bought a brand new 1993 Bronco and that engine made the strangest knocking noise too. He worried and kept bringing it back but never solved the problem. That thing is now rusting and falling apart but the engine is still running great!

Just be carefull when you start having people take things apart like the engine. Some things are just better off left alone. That is just my opinion.