Occasional rattling sound at idle

rjschof

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Okay, here's the deal. I am going to try and describe this with as much detail as I can to see who else has the problem and what might fix it. This is extremely difficult to diagnose because it is intermittent, but it is always for a few minutes after the car is turned on.

Occasionally, when I first start the car, I get a fairly loud vibration/rattle that sounds like it is coming from the engine compartment. The sound remains when I turn the AC/blower fan off. When I start moving, the sound goes away, but if I stop and idle, the sound is back. The sound tends to be noticeable more often when I am shifted into Reverse or Drive. After everything warms up, the sound appears to go away. The pattern of the rattling sound itself is similar to the sound that the exhaust makes when you stand by it if the car is on.

My theory is that the exhaust rattles a lot and the vibration itself is moving all the way up to the engine. This is causing the sound to sound like it is coming from the front of the vehicle when I am sitting in the driver seat.
  1. Does anyone else have a similar issue?
  2. Did anyone get this resolved by a dealer?
  3. Do you think it is actually the exhaust, or something else?
If it will help, I will try to get it on video and upload it here.
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hicompb18c1

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Bumping. My Si (1.5) only has 5k miles on it and i get a weird intermittent noise like this at idle too. It's not the normal DI "clicking" sound.

It sounds like a squeaking or rattling, like maybe something is rubbing or vibrating. The sound appears loudest towards the back & driver's side of the motor, but I can't tell.

- It only happens at idle, giving it even the tiniest bit of gas makes it go away instantly

- Happens with the AC on or off

- Doesn't sound like it's coming from any of the belts... Again, not 100% sure

- Motor is stock and I haven't added/moved anything in the engine bay.
 

Barticus520

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I just noticed a similar noise a few days ago. 2017 civic sport touring with 78000 miles. Just started. The noise seems to be coming from the passenger side dash area. With the ac on or not and really only when starting from park.
 

jcreamer

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I own a 2017 accord, but after searching forums for months trying to solve my own rattling/vibratory noise when at low idle/reverse I noticed that this seemed to be a common issue with many 2015 - 2018 Honda models.

By blind luck I decided to play a hunch and low and behold think I've found the culprit.

For whatever reason (noise reduction?) my radiator and fan assembly are not bolted to the frame on the top corners, but rather loosely held by a plastic peg moulded into the radiator chassis seated in rubber grommet in the engine bay. It is my suspicion that at low idle and reverse the resonate frequency generated is low enough to cause the peg to vibrate in the 1/8" gap around the grommet center.

I ended up jammimg a thin piece of plastic (splice cap cover) around the peg to reduce the gap between it and the grommet then used a bit of clear silicon to semi-permanently attach it.

So far so good. Think I've got one more rattle crossed of the list!

Hopefully this will help someone else save their precious time and energy solving their own rattling/vibration issues.

Honda Civic 10th gen Occasional rattling sound at idle 20201021_222119


Honda Civic 10th gen Occasional rattling sound at idle 20201021_222055
 


 


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