Interior Teardown - Chasing Down the Rattles
10-11-2012, 09:49 AM
#1
Drifting
Thread Starter
Interior Teardown - Chasing Down the Rattles
The interior on my 94 looks pretty good, but it rattles pretty bad. Before anyone says that it’s not a Cadillac, etc – understand that it rattles BAD. I’m abandoning my Magnaflow exhaust in the near future in favor of a stock system and I fear that all these rattles will make me insane. Honestly, it so bad that I’m embarrassed to give anyone a ride when the roof is on (roof off, wind, engine noise masks the rattles pretty good).
I know the C4 is known for its squeaks and rattles but during my own stereo system install I found evidence of a prior stereo system install and likely hasty removal along with the tell tale signs of wire splices in the audio system wires, etc. I think that is the cause for my extreme condition. I’m willing to bet the car had large subwoofers at some point as well that taxed the aging C4 interior. I don’t have subwoofers in the car – just replaced the aging Bose system for an aftermarket unit and ran speaker wire to new speakers – no plans for big bass or anything like that.
The rattles I’ve identified thusfar:
-Both door panels, which also sag.
-Possibly the window glass when rolled down – it needs new felt guides
-The dashboard where it meets/comes close the drivers door – possible contact squeak
-All the a/c vents are loose (some have broken mounting tabs)
-The clear plastic window over the gauges
-Something in the center console/shifter area
-Something over towards the passenger side dash (can’t pinpoint)
-The plastics in the hatch area
-The hatch shade when in the retracted position
And, I’m sure a dozen or more things that I just haven’t identified YET.
Is it too far gone? I don’t mind investing the time to tear it all down but I’m not sure if I can identify the squeaks and/or fix them? A major hurdle I have is that it obviously only squeaks when the car is running and things like rough roads make it worse. So it’s really tough to identify problem areas when the car is in the garage.
At minimum I want to remove/repair the door paneals and felt guides, the rear plastic parts in the hatch area, the center console and remove the dashboard to identify anything broken/loose. I think those areas are probably at least 85% of the annoying sounds.
I definitely want to add some kind of sound barrier –but not decided on brand yet, been reading/comparing. Can these Dynamat-style sound barriers be applied to the inside of the door panels or underside of the dash? Or are they strictly meant to be bonded to BODY panels only to block out road noise?
The one part that has me worried is the dash. My FSMs are buried in storage (trying to sell the house so most of my tools/stuff is in storage). Is there an easy plan of attack to get the upper dash pad off? What about removing the seats?
Looking for any advice/been there done that’s, etc.
I'll be happy to post pics of the teardown as I go if anyone is interested.
I know the C4 is known for its squeaks and rattles but during my own stereo system install I found evidence of a prior stereo system install and likely hasty removal along with the tell tale signs of wire splices in the audio system wires, etc. I think that is the cause for my extreme condition. I’m willing to bet the car had large subwoofers at some point as well that taxed the aging C4 interior. I don’t have subwoofers in the car – just replaced the aging Bose system for an aftermarket unit and ran speaker wire to new speakers – no plans for big bass or anything like that.
The rattles I’ve identified thusfar:
-Both door panels, which also sag.
-Possibly the window glass when rolled down – it needs new felt guides
-The dashboard where it meets/comes close the drivers door – possible contact squeak
-All the a/c vents are loose (some have broken mounting tabs)
-The clear plastic window over the gauges
-Something in the center console/shifter area
-Something over towards the passenger side dash (can’t pinpoint)
-The plastics in the hatch area
-The hatch shade when in the retracted position
And, I’m sure a dozen or more things that I just haven’t identified YET.
Is it too far gone? I don’t mind investing the time to tear it all down but I’m not sure if I can identify the squeaks and/or fix them? A major hurdle I have is that it obviously only squeaks when the car is running and things like rough roads make it worse. So it’s really tough to identify problem areas when the car is in the garage.
At minimum I want to remove/repair the door paneals and felt guides, the rear plastic parts in the hatch area, the center console and remove the dashboard to identify anything broken/loose. I think those areas are probably at least 85% of the annoying sounds.
I definitely want to add some kind of sound barrier –but not decided on brand yet, been reading/comparing. Can these Dynamat-style sound barriers be applied to the inside of the door panels or underside of the dash? Or are they strictly meant to be bonded to BODY panels only to block out road noise?
The one part that has me worried is the dash. My FSMs are buried in storage (trying to sell the house so most of my tools/stuff is in storage). Is there an easy plan of attack to get the upper dash pad off? What about removing the seats?
Looking for any advice/been there done that’s, etc.
I'll be happy to post pics of the teardown as I go if anyone is interested.
10-11-2012, 07:46 PM
#4
Instructor
Not that I have done this yet but my recommendation would be to go slow. Start with the doors replace all the seals and the glides tighten everything up and lubricate what needs it. Then take it for a ride. Move on to the next part after that, I have a lot of squeaks and rattles also but I found just tightening up the screws in the plastic and greasing the rear hatch made a huge improvement. It seems that just replacing the seals made a big difference in rattles because the doors and hatch tightened up. Good luck and post what you find...
Art
Art
10-14-2012, 03:08 PM
#5
Drifting
Thread Starter
Pics, progress and questions.
I've so far remove all the interior plastic trim except for around the halo. I got the dash pad and gauge cluster out as well. Haven't touched the doors. Along the way I've found plenty of signs that someone has been in here before and didn't take as much care as me. Broken plastic tabs, loose screws, etc.
So I have a few questions...
First, the below is a pic of the clear plastic facing that overlays the gauges. I've had this cloudyness since I've bought it. What can I do to clear it up? I was thinking one of those headlight restore products might do it.
Second, the bulbs in the gauges. Now, I don't have any out but with my luck right after I get this all back together I'll have one burn up. I can get these bulbs in LEDs which should last the life of the car. The bulbs are easy to remove from the cluster, just twist/pull. But they are sorta attached to this plastic piece that says 'replace entire asm.' Anyone deal with this before? Can you get a new bulb into this weird plastic piece or are these bulb/housing units a dealer piece? I especially want to change the signal bulbs for a brighter LED as I feel they are so dim I can barely see them during the day. Toying with the idea of using red LED bulbs to change color to RED for the tach and gauge lighting.
Third, this connector is under the dashpad. It's a 2 pin female and didn't have anything plugged into it. Its mounted on the right side of the hood that goes over the gauge cluster. What is this for?
Around the rear glass there are 2 seals. A thick rubber one which has been removed and then a thinner hard rubber seal that I left on. It has this yellow goop all over it that feels like old grease. What is this greasy gunk?
the dash pad off:
So I have a few questions...
First, the below is a pic of the clear plastic facing that overlays the gauges. I've had this cloudyness since I've bought it. What can I do to clear it up? I was thinking one of those headlight restore products might do it.
Second, the bulbs in the gauges. Now, I don't have any out but with my luck right after I get this all back together I'll have one burn up. I can get these bulbs in LEDs which should last the life of the car. The bulbs are easy to remove from the cluster, just twist/pull. But they are sorta attached to this plastic piece that says 'replace entire asm.' Anyone deal with this before? Can you get a new bulb into this weird plastic piece or are these bulb/housing units a dealer piece? I especially want to change the signal bulbs for a brighter LED as I feel they are so dim I can barely see them during the day. Toying with the idea of using red LED bulbs to change color to RED for the tach and gauge lighting.
Third, this connector is under the dashpad. It's a 2 pin female and didn't have anything plugged into it. Its mounted on the right side of the hood that goes over the gauge cluster. What is this for?
Around the rear glass there are 2 seals. A thick rubber one which has been removed and then a thinner hard rubber seal that I left on. It has this yellow goop all over it that feels like old grease. What is this greasy gunk?
the dash pad off:
10-14-2012, 09:04 PM
#7
Melting Slicks
I have a 96 and recently tore into the interior, which at this point has involved mostly taking out the console trim plate (shifter surround) and the actual console itself; this is what I found, and I don't think it is all that unusual for these cars, especially older, or high mileage ones:
the two after mounting tabs for the console trim plate were broken off and missing in action;
the mid mount for the console trim plate, a recess in the bottom of the forward cup holder (or astray, your choice) was completely broken away from the mounting screw;
half of the lip that holds the hatch release button in the console trim plate was broken away and missing;
The console trim plate itself had cracked through in 3 places (not surprisingly, where it narrows down to almost nothing around the shifter boot);
On the console lid, the spring which holds the button closed, securing the lid in the closed position, was broken so while the lid was in the down position, it never was truly "closed";
On the underside of the console lid, the heat of the console light bulb, had softened and broken away the lid;
The console itself had no real failures, but the four hold down screws which are little sheet metal jobs seemed loose and were replaced with 1/4 inch machine screws, washers and U nuts;
I found that the locking mechanism for the console wasn't broken, it was from another vehicle and had to be rekeyed.;
lastly, the insulation / sound deadner on the tunnel iself had numerous areas that the factory had neglected to cover, and each of these (I suspect) acted like a little loudspeaker / hot plate.
Long story short, any one, or all of these, made for a squeeky ride.
the two after mounting tabs for the console trim plate were broken off and missing in action;
the mid mount for the console trim plate, a recess in the bottom of the forward cup holder (or astray, your choice) was completely broken away from the mounting screw;
half of the lip that holds the hatch release button in the console trim plate was broken away and missing;
The console trim plate itself had cracked through in 3 places (not surprisingly, where it narrows down to almost nothing around the shifter boot);
On the console lid, the spring which holds the button closed, securing the lid in the closed position, was broken so while the lid was in the down position, it never was truly "closed";
On the underside of the console lid, the heat of the console light bulb, had softened and broken away the lid;
The console itself had no real failures, but the four hold down screws which are little sheet metal jobs seemed loose and were replaced with 1/4 inch machine screws, washers and U nuts;
I found that the locking mechanism for the console wasn't broken, it was from another vehicle and had to be rekeyed.;
lastly, the insulation / sound deadner on the tunnel iself had numerous areas that the factory had neglected to cover, and each of these (I suspect) acted like a little loudspeaker / hot plate.
Long story short, any one, or all of these, made for a squeeky ride.
10-16-2012, 11:10 PM
#8
Intermediate
A small way to reduce or remove some rattles: Take a small piece of the carpet side of velcro, cut it to size to go over the location where the screw or fastener attaches. Drive the screw through it when attaching whatever piece or panel it is.. this builds a cushion and can go a long way to silencing rattles and squeeks. Also put strips of it on stretches of panels where possible, between the fasteners...
10-17-2012, 01:15 AM
#9
Le Mans Master
A small way to reduce or remove some rattles: Take a small piece of the carpet side of velcro, cut it to size to go over the location where the screw or fastener attaches. Drive the screw through it when attaching whatever piece or panel it is.. this builds a cushion and can go a long way to silencing rattles and squeeks. Also put strips of it on stretches of panels where possible, between the fasteners...
I feel lucky. My main culprit is the rear hatch panel, and of course I am on need of weatherstrip everywhere. But I find to simply take a phillips and tighten the screws helps. It's suprising how they back out just from vibration.
10-17-2012, 03:27 AM
#10
Race Director
I have a 93 and its pretty tight. Minimal rattles.
One area that took me 10 yrs to figure out was a squeak in the upper right dash.
I thought it was something behind the glovebox.
In actuality, the hood right side was squeaking (bird like chirp). Adjusting the bump stops to bring the hood tighter against the car solved this
One area that took me 10 yrs to figure out was a squeak in the upper right dash.
I thought it was something behind the glovebox.
In actuality, the hood right side was squeaking (bird like chirp). Adjusting the bump stops to bring the hood tighter against the car solved this
10-17-2012, 11:12 PM
#11
Melting Slicks
Second, the bulbs in the gauges. Now, I don't have any out but with my luck right after I get this all back together I'll have one burn up. I can get these bulbs in LEDs which should last the life of the car. The bulbs are easy to remove from the cluster, just twist/pull. But they are sorta attached to this plastic piece that says 'replace entire asm.' Anyone deal with this before? Can you get a new bulb into this weird plastic piece or are these bulb/housing units a dealer piece?
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10-17-2012, 11:35 PM
#12
Tech Contributor
"Around the rear glass there are 2 seals. A thick rubber one which has been removed and then a thinner hard rubber seal that I left on. It has this yellow goop all over it that feels like old grease. What is this greasy gunk?"
It helps the weatherstrip move when the rear window closes on it and compresses it. The intent is to keep the weatherstrip from tearing as well as ease installation.
It helps the weatherstrip move when the rear window closes on it and compresses it. The intent is to keep the weatherstrip from tearing as well as ease installation.
10-17-2012, 11:37 PM
#13
Tech Contributor
A small way to reduce or remove some rattles: Take a small piece of the carpet side of velcro, cut it to size to go over the location where the screw or fastener attaches. Drive the screw through it when attaching whatever piece or panel it is.. this builds a cushion and can go a long way to silencing rattles and squeeks. Also put strips of it on stretches of panels where possible, between the fasteners...
GM used this tact as well during assembly of the later C4s.
10-18-2012, 02:12 AM
#14
I'm getting ready to dive into my interior, replacing the carpet and installing a heat/sound barrier before I do. I purchased a interior screw kit so I know I have all the right fasteners. I'm excited to do the job because I know it will reduce a lot of my rattles! I just took a drive in my dad's unmolested 87 and was simply amazed at how tight the car was and how whisper quiet the interior was! (And it has over 100k on the odo!) Made me jealous and ready to get working on mine. 
10-18-2012, 06:16 PM
#15
Le Mans Master
Member Since: Oct 2004
Location: South-central Missouri
Posts: 6,314
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My 90 ZR-1 is rattle and squeak free. I've noticed a number of panels with a strip of tape on them where the piece comes in contact with another piece. Velcro is used in several places too. The theme seems to be to avoid hard plastic to rub against hard plastic (or rubber) w/o some barrier.
Good luck. We all are
to see how ya fare on this endeavor!
P
Good luck. We all are
to see how ya fare on this endeavor!P
10-18-2012, 07:08 PM
#16
Safety Car
10-21-2012, 12:30 PM
#18
Race Director
There are little pieces of felt, etc. everywhere ! on my 93. They must have been factory installed.
Some examples of places they were installed at include the top of the instrument cluster (rectangle strips in 3 places on the left, center, and right side).
Also big strips where the hood meets the cowl. These pieces are on the hood-side of the interface.
In fact, my 93 factory service manual has many pages devoted to squeaks, rattles, and how to eliminate them (even how to listen to the rattle and determine where its coming from. lol. much like if you were reading a book about bird calls or something).
Some examples of places they were installed at include the top of the instrument cluster (rectangle strips in 3 places on the left, center, and right side).
Also big strips where the hood meets the cowl. These pieces are on the hood-side of the interface.
In fact, my 93 factory service manual has many pages devoted to squeaks, rattles, and how to eliminate them (even how to listen to the rattle and determine where its coming from. lol. much like if you were reading a book about bird calls or something).
10-21-2012, 01:24 PM
#19
Team Owner
Member Since: Sep 2003
Location: Freedom is never more than one generation away from extinction.
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St. Jude '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-‘19-'20-'21-'22-'23-'24
One good suggestion for eliminating squeaks is to attach a small piece of velcro (Loops) to the locations at obvious wear/contact points.
I also dip (sparingly) the ends of the attaching screws in black RTV to secure the screws.
Don't need much and its very easy to remove them when needed.
I also dip (sparingly) the ends of the attaching screws in black RTV to secure the screws.
Don't need much and its very easy to remove them when needed.
10-21-2012, 06:58 PM
#20
Drifting
Thread Starter
Been busy working on this...
I have a all of the interior panels off including the dash - but still haven't touched the doors.
I bought a hot glue gun and many sheets of felt. Cost... $15.
I have been adding felt all over the place. Anywhere there is plastic on plastic contact felt was added. I'm in the process of putting it back together and already found that I've eliminated many squeaks that I was able to identify before tearing it down.
I also managed was to find some very bright LED lights for the dash gauges. In red.. and WOW what a difference. My camera (iPhone) hasn't been able to capture the brilliance of the gauge color so no pic yet. If I can get my hands on a better camera I'll share a pic because the red led lit gauges made my dash look like something you'd find in showrooms today. Even the LCD screen lights up red now instead of orange.
I've also replaced the aging (in looks at least) shift **** with a delrin one made for a C5 (same threads as C4 shifter). I'm waiting on a new shift boot I ordered from redlinegoods. Once the boot arrives and I get the console back together I'll show off the new setup and hopefully get a good shot of the red backlit gauges.
I have a all of the interior panels off including the dash - but still haven't touched the doors.
I bought a hot glue gun and many sheets of felt. Cost... $15.
I have been adding felt all over the place. Anywhere there is plastic on plastic contact felt was added. I'm in the process of putting it back together and already found that I've eliminated many squeaks that I was able to identify before tearing it down.
I also managed was to find some very bright LED lights for the dash gauges. In red.. and WOW what a difference. My camera (iPhone) hasn't been able to capture the brilliance of the gauge color so no pic yet. If I can get my hands on a better camera I'll share a pic because the red led lit gauges made my dash look like something you'd find in showrooms today. Even the LCD screen lights up red now instead of orange.
I've also replaced the aging (in looks at least) shift **** with a delrin one made for a C5 (same threads as C4 shifter). I'm waiting on a new shift boot I ordered from redlinegoods. Once the boot arrives and I get the console back together I'll show off the new setup and hopefully get a good shot of the red backlit gauges.