Hi, I'm an engineer, tell me about your sunroof
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2008-2013 Cadillac CTS General Discussion Discussion, Hi, I'm an engineer, tell me about your sunroof in Cadillac CTS Second Generation Forum - 2008-2013; I am posting here looking for some information about the kind of sunroof issues that have been discussed in several ...
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    WillK is offline Cadillac Owners Fanatic
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    Hi, I'm an engineer, tell me about your sunroof

    I am posting here looking for some information about the kind of sunroof issues that have been discussed in several of the threads on these forums. Before I get into more detail, I'd like to share some information about the sunroof which might be of interest. I'll forewarn anyone who is reading this, being that I'm an engineer I tend to get wordy - I'm just trying to be complete and precise with the information I provide as background. If you don't want to read the whole thing but have had sunroof wind noise, please skip to my questions at the end of this post.

    So, first off I wanted to state that the sunroof I'm interested in and which I will discuss is the 2nd generation CTS sedan sunroof (2008 model year and to present). This particular sunroof has 2 glass panels, the rear panel is fixed and the front panel articulates. The front panel tilts up at the rear for vent position or moves down and then to the rear for open position. Beneath the glass panels, a powered (as opposed to manually operated) sunshade can be used to block out sunlight.

    I have read some posters describe a center support. In fact, this component is not a structural component at all. This part acts as a water channel for any water that passes through the rubber seal around the edge of the glass panels. The water channel is basicly spring loaded up against the panel, and while operating the sunroof to open the water channel is moved down so the front glass panel can move by.

    Of course, there is also channels around the periphery of the sunroof under the glass seals, the center channel drains into this and from there the water runs into drain hoses at all four corners and our into the wheel wells to drain onto the ground.

    I have read that a service procedure exists for resolving wind noise issues through glass panel adjustment. And I also have read that a simple diagnostic for wind noise which could be fixed at the dealership through glass panel adjustment is that if you can stop the wind noise by pushing up on the center water channel, then it can be fixed by readjustment.

    When you consider the system description above, perhaps it makes a little more sense as to why pushing up on the center water channel can stop wind noise. What is happenning is that air is going through the rubber seal between the two glass panels. Pushing up on the water channel results in the water channel acting to block the air from passing into the passenger compartment.

    Glass adjustment is very significant for proper sunroof function. If the glass position was overcompressing the seal on one side, it would be likely that seal wear could happen on that side (and the other side would probably be undercompressed). Undercompressed seal would result in a leak - which is most likely to be noticed as an air leak, but water might be less likely to be observed because rather than leaking into the passenger compartment, it should just drain out through the water management system (the water channels and drain hoses). Left untreated, an overcompressed seal would be likely to eventually become torn.

    Another piece of information about the sunroof is that it has an anti-pinch operation feature. This is actually something which will be getting to be common on new cars, IIRC it isn't a regulatory requirement in the US but it is in Europe and any vehicle sold in another country where it is required is likely to just carry the feature across offerings in all countries. What anti-pinch means is that the electric motor which opens and closes the glass panels includes electronics which monitors the power consumption of the motor, and if a current draw is detected which corresponds to a certain amount of load the sunroof must stop closing and change to an openning state.

    Those of you reporting that express close sometimes results in the glass openning when it is near closing, this most likely indicates the motor is seeing a current draw which exceeds expected values. This is referred to as a false reversing condition (it wouldn't really be a false reversal if this happenned because of something blocking the sunroof, it's intended to work the same as a garage door openner safety feature.)

    At this point, let me tell a little bit about myself. I am an engineer at GM and my area of responsibility does relate to sunroofs. The information I am sharing and will be able to share are either pieces of general engineering principles or otherwise easily found information about current production vehicles. There is, of course, things which I know about vehicles under development or development processes which I can not and will not be able to discuss. I am also not to make any commitments about any particular actions. What I can offer is that whatever concerns I learn about here will be heard, and I can tell you that when a car is repaired by a dealership under warranty that engineering is involved.

    In this case, I am looking for information that goes a little beyond the kind of information that can be found through the warranty process.

    My questions:

    For those who have had or are having a wind noise issue with a CTS sedan sunroof, I'm interested in hearing about what the conditions are when you hear this. Is it only at or above a particular speed or after a particular operation? (Do you hear it after closing the sunroof from vent position or from closing it from the open position, or do you hear it from eather position) When (how many vehicle miles) did you first notice? Has an attempt been made to fix it and what can you tell to describe it? Have you noticed any other noises during the operation of the sunroof, or if you have had it fixed have you noticed any other change to noises made during sunroof operation?

    I am also interested in hearing about anyone with the wind noise issue, did you also have false reversal issues? Or if you had the sunroof readjusted, did it also resolve (or cause) a false reversal issue?

    And also, I'd like to hear if anybody might have had any other issues where glass adjustment resolved their issue.

    A part of the reason for my questions that I can share is this: In general, wind noise issues are observed in pre-production testing can only be tested in full vehicle testing. The sunroof module can be tested outside of a vehicle earlier, but this kind of testing doesn't involve air moving over the vehicle. The sooner an issue is identified in testing, the greater the ability of engineering to improve the design. The answers to this question are about getting data for studying whether some wind noise issues are related to other indicators that can be detected earlier in the product development process.

    If you are able to send me a PM you are welcome to do so, particularly if you'd like to discuss over the phone or by e-mail, but I'll take info any way that anyone is comfortable sharing it. And feel free to ask other questions, but bear in mind that there are some things I may not be able to answer.

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    12 CTS Touring's Avatar
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    Thumbs up Re: Hi, I'm an engineer, tell me about your sunroof

    WoW! No answers for questions, because I'm waiting for my CTS to be built.

    Profound gratitude for taking the time to make this so clear. Your commitment is apparent and your contribution to GM is obvious. Thank you WillK.

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    MoFex's Avatar
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    Re: Hi, I'm an engineer, tell me about your sunroof

    Wow! So GM really is trying to change. Good to see first the Customer Service personnel gets involved on this forum and now GM engineers. It is encouraging. As you said warranty data does not give you the full picture, you need to reach to real people to learn more.
    And receiving a handwritten post card from a Cadillac Engineer it is something! And yes, it did happen to me
    WillK,
    To answer some of your questions. In my case the noise was audible at highway speeds. Pushing the center water channel would stop the noise. It took three visits to the dealership to solve this problem, first visit was the usual “could not hear anything”, “they all do that”, second visit had a similar outcome but I had a serious discussion with the Service Manager so finally they fixed it. The work order states replacement of seals on both stationary and articulating glass panels. Since then the sunroof has been flawless.
    Hope, it helps you with future design changes.

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    Megathumper is offline Cadillac Owners Member
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    Re: Hi, I'm an engineer, tell me about your sunroof

    I have a 2008 AWD sedan.

    The noise is so bad at highway speeds that I can not use either a cell phone or the car phone.
    I do not have the problem with the sunroof closing and reopening in error.
    I have had it at the dealer several times and they say that they have 'realigned' the sunroof. But they also say that no adjustment was necessary.
    The problem is less noticeable for a few miles after leaving the dealer, but once highway speeds are reached, it comes back soon.
    Once you open the sunroof and close it, it is really bad.
    If you open the roof in vent mode and close it, it will sometimes get a little less noisy.
    If you push up on the center, the noise is greatly reduced but still some noise.
    Not sure what speed the noise get noticeable but it is there at 40-50 for sure, just not as bad as at 70.
    I have to keep the radio volume high to over come the wind noise. And turn it way down at stop lights etc.
    I have not noticed any water leaks but I have not looked for them either.
    I got the car this year, and it has been like this since I drove it home, I did not notice it on the test drives but I was talking with sales man and etc. It now has about 53k miles.

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    Re: Hi, I'm an engineer, tell me about your sunroof

    Hi Will,

    Here's some answers as they pertain to mine:

    I hear the noise above approximately 45mph and it does get worse with increased speed. I do have the auto-reversing issue and have not had the TSB pertaining to that issue done (replace both roof and shade motors). The noise is worse if I close the sunroof from open; it's reduced if I close it from the vent position. The noise seems to vary with temperature as well as ambient wind speeds, louder when it's colder outside and louder when it's windy. I purchased the car at 48k miles in Mar. 2010 and have always had the noise. It has not gotten any worse and by the time I noticed the abnormality of it I was out of bumper to bumper so I have not taken it in to a dealer

    Though I have not taken it in, there are a few observations I have about the roof on the car right now:
    1. The glass is perfectly level both with the roof and with itself (front and back panes). It also appears to have perfect alignment along the sides as well; no part of the glass seal is more compressed or worn than another either on the front, back or sides so this does not seem like it is the issue with mine.
    2. The drip channel does not appear to be formed to the curvature of the roof. The seals on the drip channel do not touch the roof panels in the middle unless pulled partially out of the drip channel. When looking at the drip channel seals, they appear to be permanently compressed and are not rebounding back to what looks to be their natural position.
    3. If I close the roof from open, all of the noise I hear comes from the middle where the front glass meets the rear glass. If I close it from vent position, I seem to get some noise from the front of the front glass as well as some from the middle, however this combo of noise is quieter than the noise from the middle when closing from open.+

    I've talked a little bit with a Cadillac Technician on here and after consulting with him I am considering replacing all seals (front and back glass, both drip channel seals) as well as the drip channel itself (he has had good luck going this route on cars with the issue). It's a bit costly to do it all just for parts and it is something I would attempt myself. Just not sure if it's worth spending the $$ yet because I usually just turn the radio up. Any thoughts or help you could provide would be greatly appreciated.

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    Re: Hi, I'm an engineer, tell me about your sunroof

    As far as I've been able to tell then wind noise is due to the sunroof seals and center drain seals drying up and getting hard which causes them not to seal to the body or glass respectively. It could easily be fixed by replacement of the seals and drain, but it seems like most techs don't know about it.

    The real problem is they're really hard to adjust correctly so after the tech attempts to adjust for 2 hours with only slight progress they just give up (they're losing money at that point). Which causes a comeback and another tech gets it and messes it up farther and it goes on and on.

    I think the noise can be fixed pretty easily, but the techs need to be educated and they need to be really paid for the adjustment, because it can take a very long time, so they dont just say F it and ship the car.

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    Re: Hi, I'm an engineer, tell me about your sunroof

    I had a 2008 CTS 3.6DI for 39 months and have had a 2011 CTS Premium for the last 3 months. I've never had any problems with the CTS's sunroof or with noise cause by it it. But then I don't use the sunroof, even though I live at the beach in Southern California.

    To tell you the truth, I think sunroofs are one of the silliest features of modern cars -- I've had one on every car I've owned for the last 30 years (three Toyotas, an Acura, two Infinitis, four Mercedes, and now two Caddies) only because they were part of the premium packages I always opt for. In those 30 years, I've probably opened the damn things fewer than 50 times, and always closed them within a few minutes due to the noise, wind, sun, heat, cold, exhaust, etc., etc. Nearly every person I know feels the same -- sun roofs are silly!

    So here's how I'd fix the problem: offer sun roofs as a separate option only. I'll bet 95% of buyers would opt not to have them.

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    Joe
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    Re: Hi, I'm an engineer, tell me about your sunroof

    First I would like to thank you for your help. In the past 2 months I have experienced sunroof water leaks, wind noise and a full repair from Long Cadillac here in MA. The entire liner was taken down, seals replaced and drainage tubes cleaned or replaced. The dealer replaced all the rugs and paid for my loaner vehicle. I did notice wind noise after the repair. I brought it back, they made a slight adjustment because they did not want the roof to leak again. The noise was most noticeable at speeds above 50 and it got progressively louder as I went faster. I could visibly see the front glass was slightly higher than the rear glass. I brought the vehicle back again and after it was road tested by a team they adjusted the glass and the noise is gone. I might add I did push up on the center member and the noise would go away prior to the repair. Thank you again for your help.

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    Re: Hi, I'm an engineer, tell me about your sunroof

    Quote Originally Posted by tonyfort View Post
    I've talked a little bit with a Cadillac Technician on here and after consulting with him I am considering replacing all seals (front and back glass, both drip channel seals) as well as the drip channel itself (he has had good luck going this route on cars with the issue). It's a bit costly to do it all just for parts and it is something I would attempt myself. Just not sure if it's worth spending the $$ yet because I usually just turn the radio up. Any thoughts or help you could provide would be greatly appreciated.
    I wouldn't be fortunate enough that you live in the Detroit metro area to take a look?

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    Re: Hi, I'm an engineer, tell me about your sunroof

    Quote Originally Posted by The_Judge View Post
    So here's how I'd fix the problem: offer sun roofs as a separate option only. I'll bet 95% of buyers would opt not to have them.
    It's a tricky game that really falls more under the marketting and financing people than the engineering people. I understand what you mean, I've been through new car buying and seen the encouragement of sunroof due to increased resale - and for my part it's part of the sales shell game.

    The downside of less sales on an option is that the tooling dollars get spread out across less units, so either the capital expenditure is being paid out of the car price even when it's not being bought or the option gets more expensive.

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    Re: Hi, I'm an engineer, tell me about your sunroof

    Quote Originally Posted by Joe View Post
    First I would like to thank you for your help. In the past 2 months I have experienced sunroof water leaks, wind noise and a full repair from Long Cadillac here in MA. The entire liner was taken down, seals replaced and drainage tubes cleaned or replaced. The dealer replaced all the rugs and paid for my loaner vehicle. I did notice wind noise after the repair. I brought it back, they made a slight adjustment because they did not want the roof to leak again. The noise was most noticeable at speeds above 50 and it got progressively louder as I went faster. I could visibly see the front glass was slightly higher than the rear glass. I brought the vehicle back again and after it was road tested by a team they adjusted the glass and the noise is gone. I might add I did push up on the center member and the noise would go away prior to the repair. Thank you again for your help.
    See, they're very hard to adjust properly. No noise before the repair, but as soon as they remove the glass for a repair, a noise comes along (improperly adjusted).

    I think replacement seals and gutter, plus a good technician fixing it would resolve 95% of wind noises (quite a few rattles too).

    Water leaks, squeaks and rattles from the sunroof are a whole 'nother story though. Don't get started.

    What kind of engineer are you?

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    Re: Hi, I'm an engineer, tell me about your sunroof

    Quote Originally Posted by Delta View Post
    As far as I've been able to tell then wind noise is due to the sunroof seals and center drain seals drying up and getting hard which causes them not to seal to the body or glass respectively. It could easily be fixed by replacement of the seals and drain, but it seems like most techs don't know about it.

    The real problem is they're really hard to adjust correctly so after the tech attempts to adjust for 2 hours with only slight progress they just give up (they're losing money at that point). Which causes a comeback and another tech gets it and messes it up farther and it goes on and on.

    I think the noise can be fixed pretty easily, but the techs need to be educated and they need to be really paid for the adjustment, because it can take a very long time, so they dont just say F it and ship the car.
    Quote Originally Posted by tonyfort View Post
    I've talked a little bit with a Cadillac Technician on here and after consulting with him I am considering replacing all seals (front and back glass, both drip channel seals) as well as the drip channel itself (he has had good luck going this route on cars with the issue). It's a bit costly to do it all just for parts and it is something I would attempt myself. Just not sure if it's worth spending the $$ yet because I usually just turn the radio up. Any thoughts or help you could provide would be greatly appreciated.



    You would think this WOULD fix the issue but it does not. I had to fight with the dealer after their 5th time trying to fix the air noise. This last time the seals and entire sunroof system minus glass was replaced and the noise is still their. Plus I just noticed that plastic tray that moves up when roof is open was never put back, the roof shutters when open/closing, my headliner hard backing is ripped allong with the fabric on the A pillar covers. SO now not only do I STILL have the wind noise at highway speeds 60+, now when the roof is open I have turbulant air coming in which was taken care of with that plastic windage tray or whatever its called. I will take pictures of the sloppy seal job (thank God its not leaking) and post tomorrow.

    I have had it with Cadillac!

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    Re: Hi, I'm an engineer, tell me about your sunroof

    UPDATE.

    The noise is back!
    We took an advantage of gorgeous weather and made our yearly “pilgrimage” to Blue Ridge Parkway to watch fall color (absolutely stunning!). One of the first thing I noticed in the morning was wind noise coming from the center of the sun roof. Gently pushing the gutter made it disappear. So I am back to square one!

    Back home I looked around and it seems everything is aligned properly. So I decided to do a simple test. I took a sheet of paper from my printer and tried to insert it between front and back glasses – it went in very easily!
    I believe the culprit of the noise issue is incorrect seal design or seal material. It either looses the elasticity (or what ever the technical term is) or simply is bad design.
    It is my third car with a sunroof and the first one with problems. Then again the previous ones were not GM cars.

    WillK,
    I hope you are working on a solution to this problem. If you find one I volunteer to donate my time and car so you can test it. In the meantime I will try to clean the seals and treat them with restoring oil. Maybe this will help. There is always the super glue but it would be a shame to resort to such a drastic measure.

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    Re: Hi, I'm an engineer, tell me about your sunroof

    Quote Originally Posted by TeamZambo View Post
    You would think this WOULD fix the issue but it does not. I had to fight with the dealer after their 5th time trying to fix the air noise. This last time the seals and entire sunroof system minus glass was replaced and the noise is still their. Plus I just noticed that plastic tray that moves up when roof is open was never put back, the roof shutters when open/closing, my headliner hard backing is ripped allong with the fabric on the A pillar covers. SO now not only do I STILL have the wind noise at highway speeds 60+, now when the roof is open I have turbulant air coming in which was taken care of with that plastic windage tray or whatever its called. I will take pictures of the sloppy seal job (thank God its not leaking) and post tomorrow.

    I have had it with Cadillac!
    lol, that sucks

    a bad design + a bad technician = no chance at the noise being fixed

    Quote Originally Posted by MoFex View Post
    UPDATE.

    The noise is back!
    We took an advantage of gorgeous weather and made our yearly “pilgrimage” to Blue Ridge Parkway to watch fall color (absolutely stunning!). One of the first thing I noticed in the morning was wind noise coming from the center of the sun roof. Gently pushing the gutter made it disappear. So I am back to square one!

    Back home I looked around and it seems everything is aligned properly. So I decided to do a simple test. I took a sheet of paper from my printer and tried to insert it between front and back glasses – it went in very easily!
    I believe the culprit of the noise issue is incorrect seal design or seal material. It either looses the elasticity (or what ever the technical term is) or simply is bad design.
    It is my third car with a sunroof and the first one with problems. Then again the previous ones were not GM cars.

    WillK,
    I hope you are working on a solution to this problem. If you find one I volunteer to donate my time and car so you can test it. In the meantime I will try to clean the seals and treat them with restoring oil. Maybe this will help. There is always the super glue but it would be a shame to resort to such a drastic measure.
    a piece of paper might be a little too thin. i would use a credit card or an id badge and jam it between the body and the seals. youll be able to see where some places it's really easy to insert and some places there's quite a bit of resistance

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    Re: Hi, I'm an engineer, tell me about your sunroof

    Quote Originally Posted by WillK View Post
    I wouldn't be fortunate enough that you live in the Detroit metro area to take a look?
    No, unfortunately I'm in North Carolina. Anyone down here you could have look at it for you? If not I can probably take a few photos if you'd like; PM me if you are interested.

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