Car people, little help please, tapping noise

[Barrak]

Driving along, suddenly the oil pressure goes to 0 and a tapping noise starts. Pull over, stop and turn off the car. Out of curiosity, started the car again, oil preasure is back to normal, but tapping noise is still there, although, not as loud, car seems to run fine. This happened to my sisters car over the weekend. If it is something simple I will fix it for her, but I'm not sure what it is. Ideas please

 

[Mr.IncrediblyBored]

Start the engine and open the hood. Try to find the general location where the tapping noise is coming from. Could be coming from the valvetrain.

 

[Beau]

Check your vaccum system for leaks. Same thing happend to my old I-Mark, turned out to be a loose hose.

 

[blahblah99]

some cars use hydraulic rockers that depend on oil pressure to keep it adjusted. If you lose oil pressure then the hydraulic in the rockers will be soften, thus you will hear the tapping. It looks to me like you either have a big oil leak out of the engine, into the coolant system, or your oil pump is about to retire.