95_Civic_4dr

Just discovered this noise a couple hours ago, since then I've been trying to figure out the source but I have no clue...

I'm thinking water pump or the tensioner is going bad?
D16z6, it's cammed so it is a little noisy.
I can hear it more with timing belt cover off and it's more audible at idle.
http://www.youtube.com/watch?v=WTuQ1gCmfI8
Bad quality I know, had to use my phone.
If I put my stethoscope in these areas (marked in red) the sound is most audible.


I searched all over for anything loose, or signs of damage but nothing. I went over the timing belt as well looking for any wear but it all looks good, has somewhere around 75k miles on it, I don't know if the tensioner was changed as well since the car was not mine at the time.

delsolintegra

That lower cover for the timing belt could be cracked right by the bolt hole and that plastic will squeak with engine vibration. I had that problem.
How new is the water pump ? It's right behind that area.

95_Civic_4dr

No cracks that I can see.
I'm not sure of it's age, I know it's got at least 75k miles on it. I know leaking is a sign of it going bad, but what about noise? Do they tend to make a noise before going out?
My friends leaked all over the place in her Civic, but it never made a sound when it went bad.

95_Civic_4dr

Thoughts anyone? Should I drive it? Cause I really depend on this car every week, I'm not sure if I should hang up the key or not until the weekend when I can get a better look at it.

93egSLEEPER

Sounds like a tentioner.

95_Civic_4dr

I'll just replace the tensioner and water pump then. Hopefully it'll fix it.

95_Civic_4dr

Alright, nearly a month later I finally found the time to do the tensioner and timing belt. Replaced those but noise is exactly the same, I don't know what it is. I didn't replace the water pump but I spun the bearing/whatever you want to call it and it was dead quiet.

Still don't know what's causing the knocking noise, it's definitely more pronounced at 500-600 rpms and gradually disappears as rpm rises. Like I said it is cammed and has been since late '10 but never used to make this loud knocking noise.