Flapping sound when over 5K RPMs

Chuck33079 · 12-19-2015, 11:36 AM

Just going through the options logically, if it wasn't there before the service it's going to be in an area around the serviced items. Roll up under there and start looking around. If something is loose enough to vibrate against something at higher rpm, it should be easy enough to tell. Start tapping on underbody panels, heat shields, etc. My off-the-cuff guess is a slightly bent heat shield that, when the car is at high rpm, vibrates against something.

Trusting the dealer to fix it is asinine. They did it in the first place. Fixing it would be them admitting to a mistake. Get your hands dirty and figure it out. Honestly, do you want to give the dealer your car with instructions to test drive it hanging out in the top of the tach? "Here, go beat the piss out of my car and see if there's something wrong."

Duc_Z09 · 12-19-2015, 11:56 AM

Quote:

Originally Posted by Chuck33079

Trusting the dealer to fix it is asinine. They did it in the first place. Fixing it would be them admitting to a mistake. Get your hands dirty and figure it out. Honestly, do you want to give the dealer your car with instructions to test drive it hanging out in the top of the tach? "Here, go beat the piss out of my car and see if there's something wrong."

This is exactly why I've done 100% of my own maintenance from the day I got the car with 39k on the odometer; I don't trust dealerships to treat my car like I'd treat my car. So far I've done oil/filter changes, a new set of spark plugs, cabin filter ('09 didn't come with one), new battery, transmission fluid, differential fluid, and mounted/balanced a new set of 285/35/19 Potenza Pole Positions for the rear (a buddy has the equipment). I'll replace brake pads and fluid once I decide what I want... I've got about 58k on it now, 2 years this January.

The only thing I didn't do myself was the alignment (rears were at -2.2 camber for some reason

).

Chuck33079 · 12-19-2015, 12:05 PM

Quote:

Originally Posted by Duc_Z09

This is exactly why I've done 100% of my own maintenance from the day I got the car with 39k on the odometer; I don't trust dealerships to treat my car like I'd treat my car. So far I've done oil/filter changes, a new set of spark plugs, cabin filter ('09 didn't come with one), new battery, transmission fluid, differential fluid, and mounted/balanced a new set of 285/35/19 Potenza Pole Positions for the rear (a buddy has the equipment). I'll replace brake pads and fluid once I decide what I want... I've got about 58k on it now, 2 years this January.

The only thing I didn't do myself was the alignment (rears were at -2.2 camber for some reason

).

Exactly. When you ask a dealer to do fluid changes, brakes, etc, you're going to have their most inexperienced tech do those jobs. You keep your good techs for the more complicated stuff. The oil change monkey is the lowest rung on the ladder. DIY or GOOD local independent shop. Unless it's under warranty, F the dealer.

Buying tools is cheaper than paying labor.

Leingod · 12-19-2015, 12:36 PM

Quote:

Originally Posted by Duc_Z09

That would implicate the undertray since you have to remove and replace it to do an oil change. I'd think a loose undertray would react more to speed rather than rpm though.

Correct. But the undertray was tight beforehand. The sound was coming above the undertray.

Quote:

Originally Posted by Bad Boy

Can you look at the video and see if this is still similar to your previous issue?

Same exact sound. It's definitely in relation with RPM and not speed. It hasn't hurt my car at all that I've seen. So don't worry to much about it. It is an annoying sound though. If mine comes back when I pull mine out of storage in the spring, i'll start tearing stuff apart.

Bad Boy · 12-19-2015, 12:51 PM

Quote:

Originally Posted by Leingod

Correct. But the undertray was tight beforehand. The sound was coming above the undertray.

Same exact sound. It's definitely in relation with RPM and not speed. It hasn't hurt my car at all that I've seen. So don't worry to much about it. It is an annoying sound though. If mine comes back when I pull mine out of storage in the spring, i'll start tearing stuff apart.

Yeah I just checked the undertray and it seems nice and tight. Nothing looks loose. And when I rev up to the limit, 5K, no noise.
Since you said it went away on its own, ima stop stressing out with the dealer and just let it be for now.
I guess the only sure way to know what it is, is for something to actually/fully break.

Leingod · 12-19-2015, 01:12 PM

Quote:

Originally Posted by Bad Boy

Yeah I just checked the undertray and it seems nice and tight. Nothing looks loose. And when I rev up to the limit, 5K, no noise.
Since you said it went away on its own, ima stop stressing out with the dealer and just let it be for now.
I guess the only sure way to know what it is, is for something to actually/fully break.

Yea. Don't worry to much about it. About 3-4 months after I drove the car is when it went away. I did a few hard launches and shift changes during those times.

Bad Boy · 12-27-2015, 01:50 AM

Quote:

Originally Posted by Leingod

Yea. Don't worry to much about it. About 3-4 months after I drove the car is when it went away. I did a few hard launches and shift changes during those times.

Looks like you were right... After just about a week of my "normal" driving, it seems that the noise has just gone away.
I feel like there might be something loose behind the dash or something. Oh well. No noise anymore.

Chuck33079 · 12-19-2015, 01:51 PM

Quote:

Originally Posted by Bad Boy

Yeah I just checked the undertray and it seems nice and tight. Nothing looks loose. And when I rev up to the limit, 5K, no noise.
Since you said it went away on its own, ima stop stressing out with the dealer and just let it be for now.
I guess the only sure way to know what it is, is for something to actually/fully break.

Actually, you should take the undertray off and have a look before you assume everything is ok. Just because it doesn't happen when the vehicle is stationary and revving doesn't mean there isn't something contacting when the car is moving and at high rpm.

12-19-2015, 11:36 AM	#1 (permalink)
Chuck33079 A True Z Fanatic Join Date: Nov 2011 Location: Houston Posts: 12,265 Drives: 2011 370ztt Rep Power: 29540	Just going through the options logically, if it wasn't there before the service it's going to be in an area around the serviced items. Roll up under there and start looking around. If something is loose enough to vibrate against something at higher rpm, it should be easy enough to tell. Start tapping on underbody panels, heat shields, etc. My off-the-cuff guess is a slightly bent heat shield that, when the car is at high rpm, vibrates against something. Trusting the dealer to fix it is asinine. They did it in the first place. Fixing it would be them admitting to a mistake. Get your hands dirty and figure it out. Honestly, do you want to give the dealer your car with instructions to test drive it hanging out in the top of the tach? "Here, go beat the piss out of my car and see if there's something wrong." __________________ 2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

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