# CTD Interior Noise



## Robby (Mar 1, 2013)

Regarding the noise at 15mph or so......you are describing the anti lock self test.
This should occur anytime you start the car and begin driving.....the sef test only occurs going forward and is as described, rather noticeable......nothing requiring repair though.

Road noise due to the aggregate used to make roads is gonna be tough.......this is the one bugaboo that comes with unitized construction.
Body on frame designs, in addition to having rubber mounted suspension components at the frame, also enjoy rubber mounts between body and frame.
Any road noise is going to have a heck of a time transfering into the cabin on those designs.

Any unibody will carry harmonics that get past the suspension mount points into the cabin as you describe.
The manufacturers control this with sound absorption pads but yes....there is a weight penalty.....onces equal pounds.

I suspect dynomatting the entire floor and then reainstalling the factory absorption panels would help but keep in mind the whole body isn't much more than a giant tuning fork......you get some of the solidity you are hoping for but you are introducing a fair amount of weight.

If the majority of your driving is highway, there is minimal mileage impact.....but if you are a around towner, you've got to get all that added mass in motion at every stoplight......not unlike having 150lbs. of stuff in the trunk all the time.

Your car came with low rolling resistance tires and these are a somewhat harder compound to achieve the decrease in resistance.....you might end up trying a conventional (read softer) lower design pressure tire but you are playing in uncharted territory.

Or, you can try to get accustumed to it over time.

Good luck!
Rob


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## TX CTD (Oct 24, 2014)

Thanks, I thought the sound was a door lock, but the wife was sure the tranny was about to fall out. :question:

I was was hoping there would be an easier fix to the road noise than taking the complete interior out. Chevy did a good job with the firewall, it amazes me that you can't hear a fairly noisy diesel in the car. I guess I'll just have to figure out when I'll have the time to take things apart.


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## KpaxFAQ (Sep 1, 2013)

My CTD is the quietest interior of any vehicle I've owned...even with my winter tires on now....I can't imagine longing for much more..


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## diesel (Jun 8, 2013)

I have always been impressed with the quietness of mine as well.


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## TX CTD (Oct 24, 2014)

It may just be me, she had a Licoln MKZ before the CTD and my F150 is extremely quite with all the sound dreading I put in it. The other vehicles we spend time in are my folks Lexus', I'm sure it's all relative to what we are used to.

I'm going to work on the trunk and the wheel wells first, the noise seems to come more from the back than the front and those areas should be fairly easy to get to.


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## obermd (Mar 3, 2012)

TX CDT,

I don't know which trunk floor you have but there are two of them. One with sound proofing and one without.


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## Robby (Mar 1, 2013)

The MKZ and the Lexus each have rubber mounted subframes that the suspension parts are attached to.
This design mimics having a full chassis and mitigates some of NVH issues that come with a unibody.
Your F-150, of course, is a full frame and only has to contend with a body half the length of the frame.....so that one should be deadly quiet after your mods.

The rear suspension on the Cruze is attached directly to the unibody structure as are the shocks, so, yes, the rear suspension will be the noisier culprit comparing front to rear.

As obermd said....start in the trunk....there is very little deadener in there once you pull the trim panels off.

Rob


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## Tomko (Jun 1, 2013)

My CTD is very quiet as well. But I have the rare and very heavy OEM trunk mat back there. 

My DTS is definetly quieter and the audio system is better. But that whip cost twice as much and runs on michelins.


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## Su8pack1 (Apr 17, 2014)

KpaxFAQ said:


> My CTD is the quietest interior of any vehicle I've owned...even with my winter tires on now....I can't imagine longing for much more..


:iagree: Ours is very quiet on the inside.


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## money_man (Feb 25, 2014)

Tomko said:


> My CTD is very quiet as well. But I have the rare and very heavy OEM trunk mat back there.
> 
> My DTS is definetly quieter and the audio system is better. But that whip cost twice as much and runs on michelins.


Pictures of this trunk mat?


Sent from the sexy electrician


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## Aussie (Sep 16, 2012)

Don't know if this makes a difference but I have a spare where the US diesel has the fluid tank and mine is very quiet inside.


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## Tomko (Jun 1, 2013)

money_man said:


> Pictures of this trunk mat?


P/N 22990827 Cargo Mat. I paid $68. It is very thick. About 1/2". Sadly it uses up some of the already limited depth of the diesel's trunk.


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## Zenturi (Jan 25, 2014)

I sometimes hear a thump from the back when stopping the car or snapping a right turn. I'm thinking it is the DEF sloshing around, because I'm at 32% - and sometimes hear this thump a brief moment after the car is stopped. That could be a second reverberation, as it settles down.


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## warloc (Dec 10, 2013)

I also had my CTD come with the factory trunk mat which is handy for keeping things where you put them, in the trunk that is. I also feel the my CTD is pretty quiet when compared to other cars I've owned, maybe the trunk mat helps (around $100 bucks). One thing I have noticed now that I'm heading towards 40K miles, as the stock tires wear out the road noise increases inside the car. I don't think the stock tires are good for much more than 40K and IF it ever starts to rain in SO CAL, I will replace my tires ASAP.


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## TX CTD (Oct 24, 2014)

I've got a pile of sound dealing stuff coming this week (Black Friday Sale:grin. I had a originally planned to work mainly on the trunk, but after a half hour trip over the weekend I may open up the doors and have a look at what's in there instead, took some smoother roads that I don't usually drive the car on so the noise was a bit harder to pin point. 

I got a new work truck, completely stripped 15 F350 with a 6.7 and it is just amazing to me that it is almost silent on the inside, it's pretty quite on the outside as well. Took a nice little 300 mile trip today and the only noise inside is the wind going over the mirrors and that's barley noticeable about 80mph. That's my goal for the Cruze.


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