8th Generation Honda Civic Forum banner
1 - 10 of 10 Posts

· Registered
Joined
·
8 Posts
Discussion Starter · #1 · (Edited)
Hey y'all! I did a bunch of work on my '07 EX Sedan auto trans (206k miles) recently and since then I've been driving myself crazy trying to find the source of LOUD engine noise in the cabin when the car is parked and idling. Needless to say it was not like this before. The work I did:
  • New engine/trans mounts all around (followed service manual instructions)
  • New link pipe after cat to fix rust holes
  • Replaced crappy CAI c/o prvs owner with OEM ducts and filter (correct orientation)
Before the car was loud because of the exhaust leaks and induction noise through the CAI. But you could tell where the noise was coming from. Also, two of the mounts were completely blown but the car ran smooth.

Now the idle noise reverberates throughout the cabin kind of like when you're driving down the highway and crack a rear window. Low frequency noise you half feel, half hear.

Fyi the car is getting 35mpg highway with fuel trims close to zero after a reset. Starts and runs great.

I plan on putting my borescope down the front air intake/resonator chamber to see if there might be a mouse nest in there. Previous owner left it in place disconnected when they put in the crap CAI. Also checking to see if exhaust gases are escaping past the joints at the front/back of the link pipe.

Am I on the wrong track? Has replacing the mounts exposed some other issue? Surely these cars are not this loud with the stock intake. It's genuinely obnoxious.

Thanks for any $0.02 you might have!
-TA-

EDIT: It was the aftermarket mount (mostly). I replaced the passenger side mount with an OEM Honda unit from a dealership plus new bolts. Followed the service manual tightening order (plus loosening the trans and lower mts) and torque specs. The deep resonating sounds are like 90% gone. I noticed at install that the Honda mount is much more flexible; you can move it around with your bare hands. The aftermarket one I got was really stiff. Probably explains a lot, plus the Honda unit has some kind of oil damper inside. Anyway, hope this info is helpful to someone. -TA-
 

· Registered
Joined
·
8 Posts
Discussion Starter · #3 ·
Thanks FuntanaS. Yes, cheap aftermarket mounts (w/solid rubber) from 1A Auto. Some other threads seem to suggest at least the passenger side OEM Honda mount is hydraulic? If that's the case I'll definitely swap that mofo out for OEM. If not, I'll check my work. Another thread on here mentions the person misaligned one of the brackets for that mount. Once they found and fixed that, the vibes went away.

If either are the cause of this problem I'll be amazed but happy. It's a serious amount of noise and only a little vibration, especially considering there was no noise or vibration coming from the completely broken (non-OEM) mount that was in there before.

Traveling currently but will report back once I'm home and can work on the car in case it helps other people out.
 

· Registered
Joined
·
1,212 Posts
Yeah, the passenger mount is fluid filled. Not 100% sure how that all works.

It's interesting because I have a new to me 2010 Civic and I'm getting a resonance noise when accelerating at less than ~2000 rpm. If I accelerate with the engine over 2000 rpm the sound is totally gone. It also makes noise when stopped in drive. The noise gets quieter after the car has been driven for a while.

But the weird part is the mounts are all OEM and are not collapsed or broken at all.
 

· Registered
Joined
·
8 Posts
Discussion Starter · #5 ·
Huh, wish I could help but this is my first Civic. Are you sure about your mounts being ok? My passenger side mount looked fine but fell apart in two pieces when I removed it. The trans mount I could see visually was shot. The whole engine was sitting at an angle. Good luck!
 

· Registered
Joined
·
158 Posts
Hey y'all! I did a bunch of work on my '07 EX Sedan auto trans (206k miles) recently and since then I've been driving myself crazy trying to find the source of LOUD engine noise in the cabin when the car is parked and idling. Needless to say it was not like this before. The work I did:
  • New engine/trans mounts all around (followed service manual instructions)
  • New link pipe after cat to fix rust holes
  • Replaced crappy CAI c/o prvs owner with OEM ducts and filter (correct orientation)
Before the car was loud because of the exhaust leaks and induction noise through the CAI. But you could tell where the noise was coming from. Also, two of the mounts were completely blown but the car ran smooth.

Now the idle noise reverberates throughout the cabin kind of like when you're driving down the highway and crack a rear window. Low frequency noise you half feel, half hear.

Fyi the car is getting 35mpg highway with fuel trims close to zero after a reset. Starts and runs great.

I plan on putting my borescope down the front air intake/resonator chamber to see if there might be a mouse nest in there. Previous owner left it in place disconnected when they put in the crap CAI. Also checking to see if exhaust gases are escaping past the joints at the front/back of the link pipe.

Am I on the wrong track? Has replacing the mounts exposed some other issue? Surely these cars are not this loud with the stock intake. It's genuinely obnoxious.

Thanks for any $0.02 you might have!
-TA-
Did you replace with genuine OEM Honda Parts? Was it just the motor mounts you did?
 
Joined
·
3 Posts
It's definitely the mounts. I changed my mounts out to some stiffer ones, not the super stiff ones, but just more stiff than stock, and the car gets louder. I also changed my cat for a highflow cat, car got louder. I then swapped it all out for a race header, car got louder. The more things you do to make it faster and improve performance, the louder it gets lol.
 

· Registered
Joined
·
8 Posts
Discussion Starter · #8 ·
OP here: Thanks all! I watched a video on the topic in which the OEM passenger side mount was leaking oil, i.e. is a hydraulic unit. Pretty sure the cheap aftermarket one I got is not. I'll order up a new Honda unit and report back in a week or two. Not going for performance, just daily driving. Maybe if it were a manual transmission.
 
1 - 10 of 10 Posts
Top