[amitmishra4]

If possible, grab a ratchet and place the larger end to your ear and touch the other end to the metal, move if it along the engine block to find out where the sound is most prominent. Could it be a spark plug knock? I still have my doubts on the water pump. See if the noise is coming from there, should be possible to tell using the technique above.

Btw, I assume you checked oil level manually using the dipstick and the level look good? I would hesitate to run the engine much until you get your mechanics opinion.