I recently purchased my third Honda, my first two were late 70's CVCC with over 400,000 miles and still going.

I had trouble with the air conditioner, but with help from this site i was able to rebuild the blower resistor and replace the fan motor.

Other than the A/C Blower motor and blower transistor, the 08 civic has a very loud sound at about 1800 rpm.

It sounds like a exhaust resonance from a V8 chevy with 3 inch turn downs. I have checked the exhaust system and it appears to be stock. There are no exhaust leaks. It is completely quiet at idle and under acceleration. However, around 1800 rpm it is so loud that I can not hear the radio.

It resonates so loud that everything rattles.

It makes the sound in park, drive, and while driving.

Any ideas are welcome.

 

This could be about 65 million things. If you ruled out 1 thing per year since the dinosaurs died, you'd be at a resolution.

Have you tried inspecting it? Maybe looking for something causing the noise?

 

Thanks B Serious. I have inspected the exhaust, undercarriage for loose parts, engine pulleys, but I cannot locate it.

I only mention it here because it may be a common issue.

Have you ever sat in a vehicle that has a hopped-up V8 with flow masters? At a specific RPM the exhaust resonates a deep roar that activates alarms on vehicles near by.

This civic has a similar effect, only not as loud.

This is not a broken fan blade or flat spot on one of the pulleys.

 

Can you post a video with sound, so we might hear the issue? It would help steer us in the right direction. If possible, get sound from inside the passenger compartment as well as under the hood.

Thanks, wouldn't want to blame this on some loose muffler bearings now would we?!!

 

https://www.youtube.com/watch?v=Ow8d...ature=youtu.be

Here is the video for the sound. My camera did not pick up the loud sound, only a vibration. The sound is very low and loud. Although the camera did not pick up the sound, it may point to something that is causing the sound.

Just hearing the video makes me think there is a bad cylinder, but there are no engine lights on. The sound is not present at idle or over 2500 rpm.

My gut tells me that it may be a harmonic balancer (or equivalent) or motor mount. What are your thoughts?

 

After reading what others have posted as engine mount problems, I think this is the trouble. I did not see any visible damage, and it does not make noise when shifting in and out of park, so I ruled the engine mount out. However, I will be inspecting it a little closer this weekend.

 

Engine mount on passenger side is a super common failure causing lots of noise and vibration, cheap pos collapse after time.

 

It was the motor mount.

I purchased a new one at Advanced Auto Parts, they had a $50 off entire online order. I picked it up at my local store the next morning.

It took me about 2 hours to replace. I did not have the right tools so I had to improvise. A couple of deep sockets would make the job go much quicker.

Thanks M_Shake for the suggestion. The engine mount did not show visible signs of failure, but after comparing it with the new one it was clearly worn out.

Civic is running great and enjoyable to drive.

I have repaired the motor mount, A/C fan motor, and A/C fan motor relay. Is there any more foreseeable repairs in my future?