The last time I drove my car, several months ago, I'd noticed this annoying rattle that seemed to be coming from either the water pump or alternator. Months before that, I'd become convinced the rattle sound was from the idler pulley and so had replaced that, and it seemed to have helped.
Fast forward to yesterday. I got the car out of the garage and drove it to work, and was immediately greeted with the rattle noise but on a bigger scale. Today it was so loud it was driving me crazy, so I finally started digging into it again.


Turns out it was the water pump pulley! One of the four bolts was missing, and one was backed about half-way out, and the other two were loose. Put in a new bolt (with Loc-Tite) and re-torqued the others after removing, cleaning, and putting Loc-Tite on them.


The car purrs like a kitten now.

 

LOL it pays to listen to your car. Obviously if you ignored that the results could be much worse because messing with its life blood is never results in good things. Glad you found the culprit.

 

Thanks for posting. I'm pulling the IC out this weekend to clean it and clean and re-charge the air filter. Will take 30 seconds to check those bolts.