2005 Nissan Altima 2.5s help?

So i bought a 2005 Nissan Altima, 2.5s, 4 cyl engine. Before i go to the dealer to complain i did some reseach. A lot of reviews say the engine is noisy, and that is the problem i am having. When i am at a stop sign and have the raio off, the engine is way to loud, like a clack clakc sound. Is this normal of 4 cyl engines ( i have always driven a tahoe V8, and a T-bird 3.8 V6, never heard noise ) . Thanks in advance.