Q: Car is tapping

Occasionally, belt driven accessories are the source of noise so you can try to isolate all belt driven components by removing the serpentine belt and briefly run the engine. If the noise remains, a common source of tapping is the valve train. Noise there could be due to lifter failures and even inadequate oil pressure. Using an external gauge, you can check engine oil pressure. Simply speeding up the engine though, to perhaps 1,200 RPM, will normally raise oil pressure and if the noise diminishes, the cause of the noise might low oil pressure at idle. If oil pressure is low, that is either caused by a failing oil pump or is a consequence of excessive bearing clearances in the engine, the latter circumstance of course requiring engine rebuilding. If you want a conclusive diagnostic, and a repair strategy, the recommended service is an engine noise diagnostic. Please let us know if you have further concerns or questions.