Buzzing noise @ 3500 rpm under load

[Rezurexun]

2006 MZ3 2.3 GT
Under hard acceleration and also deceleration there’s a noticeable buzzing/rattling sound heard from within cabin coming from engine bay exactly between 3.5k and 4k rpm. After that it disappears. Checked all engine bay components, connections, etc. no problems found. Any thoughts?


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[Default User]

Check your grounding wires.

Have you installed any electrical components recently?

[Rezurexun]

Check your grounding wires.

Have you installed any electrical components recently?

Nothing new. I have a grounding kit but it's not an electrical type of buzzing. It sounds more like fast mechanical buzzing sound.

[morganc]

Could be a baffle in your exhaust, heatshield, or the exhaust contacting the car due to older rubber exhaust mounts

[jeff7670]

How are all the mounts? I have aftermarket ones and they have that type of buzz.

[pwdunmore]

2006 MZ3 2.3 GT
Under hard acceleration and also deceleration there’s a noticeable buzzing/rattling sound heard from within cabin coming from engine bay exactly between 3.5k and 4k rpm. After that it disappears. Checked all engine bay components, connections, etc. no problems found. Any thoughts?


Sent from my iPhone using Tapatalk

From your description it sounds like a bad motor mount.

If you have an auto, do you hear a louder than normal clunk when going from Park to Drive?

[Rezurexun]

From your description it sounds like a bad motor mount.

If you have an auto, do you hear a louder than normal clunk when going from Park to Drive?

no it doesn't have a louder than normal clunk. there's actually no clunk at all lol. i have a replacement motor mount on-hand from a Ford hybrid that i will be putting in soon -- the stiffer ones.

i also have a new transmission motor mount. let's see if that fixes the problem.

i'm going to order the insert for the passenger motor mount as well. want to make sure all of them are replaced at once :)

[pwdunmore]

no it doesn't have a louder than normal clunk. there's actually no clunk at all lol. i have a replacement motor mount on-hand from a Ford hybrid that i will be putting in soon -- the stiffer ones.

i also have a new transmission motor mount. let's see if that fixes the problem.

i'm going to order the insert for the passenger motor mount as well. want to make sure all of them are replaced at once :)

You can visually inspect the passenger and rear motor mount with a good flash light and a pry bar.

Check for visible cracks in the rubber or membrane, if you find cracks replace the mount. If there are not visible signs of wear check the mount for excessive play with the pry bar.

The transmission mount could be torn and you just need to take the battery box out for that to check it.

[Rezurexun]

You can visually inspect the passenger and rear motor mount with a good flash light and a pry bar.

Check for visible cracks in the rubber or membrane, if you find cracks replace the mount. If there are not visible signs of wear check the mount for excessive play with the pry bar.

The transmission mount could be torn and you just need to take the battery box out for that to check it.

perfect! thanks for the info! i'll start on this as soon as i get some time with the car. i'll keep you all posted! :) cheers!

[Cichlid]

I bet its the mount under the battery I have gone threw 3 of them brand new ones recently and the 3rd is on the way out I have this exact buzzing when they go out they also rattle at low rpm when releasing the clutch I cant figure out whats causing it mines a 2011 2.5L.