One of the first things a mechanic will ask you is what you think is wrong with your car. This way he'll know you're not the kind of guy he can push around. Never describe the car's problem in terms of sound. No matter what the cause of this problem, the mechanic will easily spot your stupidity and charge you two months' salary to fix it. You'll also want to learn how to change your car's oil.
All car guys know how to change their own oil.
They probably even know what it's for. This is why they know that anyone who shows up for a lube job is a sucker. I tried to change my own oil once, but I found it impossible to fit the can under my hood. For some reason, my car was poorly designed, and the hood only opens three inches at the front. So I have one of the quick-change oil places change it for me.