My car is knocking,

I have a 2008 cadaliac cts..I checked the oil stick and it didn't register ,it is knocking very loud under the hood ..don't wont to get ripped off please help I put oil in and its still knocking..scared to drive it

It all depends depends on where the sound is coming from. It could be something as simple as a partially torn belt slapping against something or as complicated as a loose piston rod. Enlist the help of someone that is knowledgeable about cars and try to locate where the sound is coming from. Once you understand what the problem is, you can shop around for the best price for fixing it to avoid getting ripped.

Get aa mechanic don't drive it your is more precious so be safe because it's machinery without seeing it no one can understand the problem.