You know how your uncle Barney makes all those sounds at Thanksgiving, and he thinks they're hilarious? Well, if your car ever sounds like Uncle Barney, you've got serious problems.
A tapping or popping that sounds like Barney doing deep knee bends (which never happens), for instance, could indicate detonation taking place within the engine's cylinders. This happens when gasoline ignites prematurely in the combustion chamber of the cylinders and can potentially result in expensive piston damage.
If you hear a grinding noise when you attempt to start your car, your starter motor might need to be adjusted or replaced. If you hear grinding when shifting between gears, it could be transmission replacement time! It's not as fun as it sounds. And if you're driving a manual transmission, do not listen to Uncle Barney when he says, "Grind it 'til you find it."
In most cases, a little bit of noise from either your car or Uncle Barney -- like a mild ticking or clicking -- might be normal. Cars with roller rockers in their valve trains, for instance, emit some ticking noise; and fuel-injected vehicles also produce slightly audible clicks from the injectors [source: 2CarPros.com].
If in doubt, listen intently, try to track down the general area of the noise as best you can and then attempt to explain it in as much detail as you can to a qualified service professional.