Car

Check if the outer steel ring is broken loose from the rubber that's sandwiched in between that ring and the hub. If it is tight, check if the center bolt is tight. If it is loose, pull the balancer off to check if the center hub is cracked.

Just to add to Doc's answer, there is an easy way to check for a broken balancer. Get a piece of chalk and make a line from the center bolt all the way to the outer edge. Now run the engine with the A/C on and shut it off. See if it is still one continuous line or not. If the outer line and inner line have separated, the out pulley is moving.

I never thought of that but I'll never admit it!

I doubt you'll hear a lifter from inside the car. They tend to get quieter as you raise engine speed unless there is a problem with the oil level / pressure.

If you can hear it when standing under the hood, use a stethoscope to look for the source. They are available from the auto parts stores for around ten bucks.

Don't overlook an oil light. That CAN lead to serious engine damage real quickly. The best test is to measure the actual oil pressure with a mechanical gauge that screws in place of the sending unit. If it shows good oil pressure, just the sending unit is defective. That's not uncommon. If pressure really is low, and increases when you increase engine speed, worn crankshaft and connecting rod bearings are the most common cause. Everything will still be getting oil but when it isn't under pressure it can't isolate the moving parts from each other.

Low oil pressure will cause the hydraulic lifters to not pump up too. The clattering will sound like a typewriter. (Typewriters were real common only ten years ago. Really!)