Knocking noise?

Maintenance/Repairs
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1

03 civic 1.7L. Knocking noise on cold start and when the car is warm while accelerating. It started with the belt squealing and getting louder on accelerating as well with the noise now. Not sure why it’s not letting me upload a video from my phone on here. Any suggestions based on the info without a video?

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Was the oil level “normal” when you checked it?
How long was the belt squealing before this noise began?

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Yea the level is normal, and I’m gonna guess maybe 2ish months of the squealing. It’s sounds like a knocking but the noise isn’t always there, maybe a bad tensioner?

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From afar, that would be my best guess. The squealing was likely an indication that the bearings in a tensioner (or even just a regular belt pulley) were beginning to go dry, causing the belt to slip. Now, 2 months later, I think that those bearings are trying to tell you something.

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With the belt squealing, I’m not sure why you’re guessing about additional noise before addressing that. (As implied by @VDCdriver ’ s comments).

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A bad belt can cause a “knocking sound”?

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Not really - no. A problem with a pulley or tensioner can cause belt noise and knocking-like noises. I’m just saying that you don’t really want to be driving around with a squealing belt no matter what. So get a new belt, and while it’s off, inspect all of the pulleys and the tensioner. You can also - briefly - start the car without the belt on to see if the knocking is gone.

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Experienced pro-mechanics are pretty good at sound diagnosis. That’s probably your best bet to get the actual cause.

As far as your vdo, new members here have certain restrictions on what they can post. In any event to post a vdo link here, I believe the poster has to first translate it to a u-tube file. It’s unlikely the sound quality will be good enough to effect a diagnosis anyway. The vdo idea is probably a waste of time.

Edit: Besides the good ideas above, knocking sounds on a warm engine can sometimes be a problem with the valve clearance, oil pressure (esp to the lifters) , or timing chain/guides.