Hi what is make and model car? Thanks
ford mustang v6 3.8 ltr 2000
The noise is most likely caused from worn out bushings in the cam shaft position sensor synchronizer assembly! These are very easily mistaken for a water pump noise, I have attached the workshop manual instructions below for this component, however it will require the use of a special service tool to line up correctly as this synchronizer is what tells the cam position sensor when to fire the injectors and spark plugs, and it is critical that it is installed correctly!
As when the bushings go out on the syncro, the now out of balance tone ring that gives the signal to the cam position sensor which is mounted to the top of the syncro is almost always damaged as well, the syncro from ford is about $147 dollars and the sensor is around $60, if you have it done at the dealer, you will be charged about one hour at your local shops labor rate, national average right now is $95 per hour! If you do the job yourself, you can get the syncro and sensor together on line for around $50 dollars for both, and buy the tool for about $36 dollars!