E46 Fanatics Forum banner
1 - 3 of 3 Posts

515 Posts
Discussion Starter · #1 · (Edited)
For the select few who are dealing with the sunroof cassette "chatter" or plastic cracking, this thread covers a possible alternative to purchasing a brand new sunroof cassette for at least $600 in parts alone. This guide will hopefully help a few people understand and go through a few steps to fix the sunroof cassette.

First let's start with the ever common Sunshade Clip Issues:

So you have played with your clips/sunshade. Maybe luckily it should have been a 1 Hr Fix and a few bucks to replace the clips. (They are cheap via RMEuropean). However there is a chance you have the following noise issues as seen in both youtube videos:



There can be a number of problems:
- the sunroof cassette in the front side of the housing ruptures causing the cable to fall out
- the cables are misaligned/kinked
- the cable tracks are lodged/dirty causing an inconsistent track
- one or more parts of sunroof mechanism is faulty causing cables to wreck havoc on the cassette & entire sunroof mechanism.

I ultimately had the worm cable come out of my housing which destroyed my sunroof system. The next best step would be to drop the headliner with the following guides:


My suggestions for dropping your headliner is either to do it fully or just drop the A/B Pillars and the few clips near the driver's side. At that point you should be able to tell if your housing is broken and if the cable is breached. My cable had breached and I could see it literally drop down the headliner. :facepalm:

515 Posts
Discussion Starter · #2 · (Edited)
1) So with Full Headliner Removal you should be able to see the entire cassette and the extent of the cable/cassette damage. For me I could see the cable dropping in & out by manually moving the sunroof motor.

2) At this point examine what needs to be fixed. Most likely it is your sunroof cassette fracturing causing the cable to leach out. To repair the housing it was suggested by both fellow E46fanatics jvidamins/figjam911 that epoxying the housing would work.

3) So with removal of the sunroof cassette with this guide:

You should be here:

You can epoxy the housing, it is pretty obvious where the plastic breaks.

Here is where my situation is unique. Upon removal of the cassette I noticed on the backside (interior facing into the steelframe of the car) there are 2 metal strips that cover the cables. These are held in by probably 6-8 T10 Torx screws. Instead of leaving them and epoxying the common plastic break areas, I removed the metal strips to see whether my cables were beyond repair.

As seen in blue, this area on the opposite side breaks usually. There are obvious cable marks near the edge of the housing. After inspecting the 2 metal covers and analyzing how the sunroof cassette is designed, BMW really did a horrible design. The 2 metal covers don't completely hide the cables even with all the Torx screws in.

So having reseated the cables I manually operated the sunroof, however I was constantly having tension at certain closing/opening positions in the cassette. With some tinkering & my partner's observation, we noticed 2 things.

1) the sunroof "rear rain wiper" mechanism was seriouslly destroyed and non symmetical unlike the proper OEM design:

2) Removing the rear wiper allowed the cables to move back and forth until both sides were flush. This enabled a perfectly moving sunroof when manually closing/opening with the allen wrench on the sunroof motor.

At this point I was in a happier mood, however to make sure the sunroof was perfectly in good order I made sure both "driver" sides were completely flush and in sync with each other. This is somewhat hard to explain so I tried to illustrate it:

The drivers (in green) that ultimately move the sunroof need to be at the same point of travel on each side:

To do this, I simply removed the original 2 metal covers and manually moved the cable till both sides were at the same points. Be sure to reseat the cable so its in the track. For me, the driver's side was lagging compared to the passenger side driver. I moved the cable closest to me to the right. (Meaning the cable closest to the edge of the cassette)

Now test the sunroof mechanism. Close the 2 metal covers, manually operate the sunroof motor. Everything should be even and clean moving without any tension.

Be sure to LUBRICATE like mad with white lithium grease. Get all the channels, cables, tracks. Everything needs to be moving again. Clean what you can.

Test the sunroof in the car with the sunroof motor running off the battery. Hopefully nothing sounds faulty. Your cable, sunshade, drivers, and etc should be perfectly lubed and running smoothly.

- The sunroof is really a bad design with how the cable tracks don't completely enclose everything. If 1 part of the sunroof breaks, it causes strain on all sorts of areas. I may just use it for the tilt function.
- It is my belief the entire reason the cables dislodge is due to strain from the many faulty sunshade clips, no greased tracks, arm drivers misaligning, etc.
- Like many people, consider just removing the sunshade so nothing constricts the movement of the sunroof.
- The sunroof motor is pretty strong, so if you have plastic cracking/grinding, STOP and diagnose what is occurring.
- I've concluded most of the time the reason sunroofs go haywire is due to the weak sunshade clips and overexerting the sunroof via the driver/lifting arms. Somehow my sunroof cables went out of sync which led to my sunshade rear wiper twisting and locking the entire mechanism.
- You can totally bend the rear wiper back to original spec! It may seem like it is welded, but my partner was able to use pliers to slowly mold it back into symmetric shape. HOWEVER, after a few days of testing I've noticed the rear wiper is out of funk with each guide and its much safer to remove it.
- Lube everything with white lithium grease, it greatly prevents any future sunroof problems
- Don't let the dealer tell you to purchase an entirely new sunroof cassette. I didn't notice any specific housings breaking. For me it was simply reseating the cable and making sure the drivers on each side were in sync.

-When removing the sunroof cassette, do not remove the bolts out of the housing. They have washers on the opposing side so you can unscrew them and leave them as is. This helps when reinstalling.
- Have patience and some good tools. My letter opener was great for plastic panels. Quality torx sets help when removing the many few in the car.


I hope this helps anyone with the same issues. Personally it took me 3 weekends of tinkering around. It helps to have a helper when removing the cassette. PATIENCE is the biggest key. That and knowing you don't have to spend $600+ just to replace a few minor parts.

Special thanks to:
demarlco/lincomatic for initial write ups
jvidamins/figjam911 for the PM/Email help regarding epoxying.

I will continue to update this thread with any tips or suggestions. Personally I'm dead tired and need a break!
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.