What I did was, opened the sunroof, and located the tabs for the plastic trim surround that holds the headliner around the sunroof hole. You can't miss 'em. I released the tab on the front right and 2 on the side right. This gave me enough play to pull down on the trim and the headliner a bit. When i did this, I noticed a line of glue/silicone material on the inside of the headliner, I wonder if this was making the noise by sticking/releasing while going over bumps? Anyhow, I took a shop rag and slowly and evenly stuffed it in between the roof and the headliner (many have used foam, and I think foam is a better solution, but I didn't have any). I then reattached the tabs, and voila, the sound is gone. Be careful when reattaching the plastic trim surround, the headliner had slipped out a bit on one side and I had to reposition it underneath.

Took me 10 minutes, not tough at all.

Good job.....where's the pics.

Good job.....where's the pics.

Damn, I knew that was coming...I will take some tonight

Damn, I knew that was coming...I will take some tonight

Thanks :thumbsup: :thumbsup:

Is it the rattle sound you get when you go over bumps on the right side (sounds like from the rear) of the car??

LFG: I have a rattle sound from the rear right, even after adding foam and corrrecting the headliner noise. It sounds like it's coming from the trunk and is noticible after hitting depressions or ripples. It is a normal tire thump noise with vibration/rattle sound along with it. I don't hear it on left side. It really bothers me, but so far the dealer has said "no trouble found". I have the 18' tires.
Is your noise similar? And, thanks for the updates during your trip.

Thanks :thumbsup: :thumbsup:

Is it the rattle sound you get when you go over bumps on the right side (sounds like from the rear) of the car??

This is different I think, in my car it's definitely coming from the passenger side front, in the headliner.

LFG: I have a rattle sound from the rear right, even after adding foam and corrrecting the headliner noise. It sounds like it's coming from the trunk and is noticible after hitting depressions or ripples. It is a normal tire thump noise with vibration/rattle sound along with it. I don't hear it on left side. It really bothers me, but so far the dealer has said "no trouble found". I have the 18' tires.
Is your noise similar? And, thanks for the updates during your trip.

I've heard this sound before too, it seems like it comes and goes. Does it almost sound like the license plate rattling? I thought it was this but the plate seems secure...

LFG: I have a rattle sound from the rear right, even after adding foam and corrrecting the headliner noise. It sounds like it's coming from the trunk and is noticible after hitting depressions or ripples. It is a normal tire thump noise with vibration/rattle sound along with it. I don't hear it on left side. It really bothers me, but so far the dealer has said "no trouble found". I have the 18' tires.
Is your noise similar? And, thanks for the updates during your trip.

Same here. I am still waiting for a fix. It seems that a number of people are experiencing the same...

Thanks guys regarding the noise in the rear. I put padding under my license plate, so I don't think it's that.
Also, sorry I got off the topic of the headliner noise.

LFG: I have a rattle sound from the rear right, even after adding foam and corrrecting the headliner noise. It sounds like it's coming from the trunk and is noticible after hitting depressions or ripples. It is a normal tire thump noise with vibration/rattle sound along with it. I don't hear it on left side. It really bothers me, but so far the dealer has said "no trouble found". I have the 18' tires.
Is your noise similar? And, thanks for the updates during your trip.

I had this same rattle and it turned out to be a loose rail for the headrest inside the rear passenger seat. I have the split seats and could replicate the noise by lowering the passenger seat back and tapping on the back of the seat. They had to open up the back seat and do something with the rail to prevent it from rattling. It is quiet now.

LFG: I have a rattle sound from the rear right, even after adding foam and corrrecting the headliner noise. It sounds like it's coming from the trunk and is noticible after hitting depressions or ripples. It is a normal tire thump noise with vibration/rattle sound along with it. I don't hear it on left side. It really bothers me, but so far the dealer has said "no trouble found". I have the 18' tires.
Is your noise similar? And, thanks for the updates during your trip.

Yes, my noise is similar.
I heard on this web site it may be the rear-right headrest.

Thanks for the info. However, I lowered the folding seat on the right side, but still heard the noise, so I don't think my problem is from the headrest on my vehicle. It sounds more like something with the right shock absorber extension and the plastic inner fender. I'm going back to the dealer again on this next week and drive another CTS and also have the service manager hear the noise. I've only have about 800 miles on the car with no other problems, so maybe I should be patient and the noise will disappear.

Think I may know what your problem is. I just found this last night, and haven't fixed it yet, but at least I know what the problem is. The plastic wheel tubs are only attached at the bottoms ,and there is one small screw at the back of the tub. At the top of the tub it slides behind the fender at the outside edge. There are no fasteners in this area, so that when the tub vibrates or flex's (mine does it at about 60-70 mph), it bangs against the metal fender. So I'm going to slide a strip of rubber between the tub and the fender. I went around all four wheel, and unfortunately they all fit differently.

Yes, my noise is similar.
I heard on this web site it may be the rear-right headrest.

I had a smiliar noise that I first thought was the screen for the sunroof. It turned out to be that the entire package tray was slightly loose. I just put my fingers on each side near the pillars and pulled it toward the rear seat. The noise is gone. I don't know if your noise is the same, but it is worth a try. You will know right away if the tray is loose.

I tapped the rear shelf with my hand and was surprised to hear it rattle a bit. I was wondering if thats what is rattling back there. On my list for the next visit. Also noticed that a white cloth or tissue is bunched over my rear passenger side speaker. Cant imagine what it is, but it looks like it could be blocking the sound from the speaker.

I tapped the rear shelf with my hand and was surprised to hear it rattle a bit. I was wondering if thats what is rattling back there. On my list for the next visit. Also noticed that a white cloth or tissue is bunched over my rear passenger side speaker. Cant imagine what it is, but it looks like it could be blocking the sound from the speaker.

That is what mine was like until I pulled it back into place. That was a few weeks ago and thus far there has been no repeat of the noise. If yours is the same, this is an easy fix. It will take you less than five minutes. Once you do it, tap the package tray again and it should not sound loose.

Hey guys, I don't have our CTS yet. What is the package tray ? Thanks

Lewis

Hey guys, I don't have our CTS yet. What is the package tray ? Thanks

Lewis

I think the package shelf is the rear deck that holds the speakers.

I think that I found a source for the rattle. The interior trim piece at the C-pillar (the trapezoidal fabric trim rearwards of the small plastic button labeled airbag) has nothing to support it where it comes to a point at the rear window. On my car it moves about an inch and is very floppy. I stuffed a piece of fabric and it seems to have stopped the rattle. If it works long term, I'll get the dealer to fix this correctly.

Think I may know what your problem is. I just found this last night, and haven't fixed it yet, but at least I know what the problem is. The plastic wheel tubs are only attached at the bottoms ,and there is one small screw at the back of the tub. At the top of the tub it slides behind the fender at the outside edge. There are no fasteners in this area, so that when the tub vibrates or flex's (mine does it at about 60-70 mph), it bangs against the metal fender. So I'm going to slide a strip of rubber between the tub and the fender. I went around all four wheel, and unfortunately they all fit differently.


I just found your post and realized I had also discovered this problem with my car. Seems I am not alone.

http://www.cadillacforums.com/forums/cadillac-cts-forum-2008-beyond/148345-rattle-highway-speeds-fixed.html

Did you solve your rattle? Did you also find there was no foam pad attached to the right side but had one on the left?