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Discussion Starter #1 (Edited)
EDITS IN BOLD BLACK TYPE (wanted to make some updates to the OP)

Some of this may be known to some old farts (e46 tenure, not age) on the forum, but I haven't heard anyone talk about it so I thought I would start a (rare for me) thread on my window regulator issues, and what I think most people are missing with regard to why they fail.

My window regulator issues started the day I bought my used 2003 325i Sedan with a failure of the driver rear window. Most of the problems are with sedans which I will talk more about later. In the few years since I bought it, I have replaced all but the passenger rear (which is making some clicking noise so I think it is soon to be replaced), and the front driver I have replaced 3 times. This is unacceptable to me. For the record, I had window regulator issues with my wife's Honda Odyssey (both passenger side) also, which is a similar design to the e46: cable/pulley/track system rather than the older scissor jack style (which works still without issue on my son's '98 Olds Cutlass). The scissor jack style and the old gear/crank lever style are far superior to the cable/pulley/track system but is probably more difficult and expensive to implement on a production vehicle hence our burden.

The theory I see most often posted on here are

1: That aftermarket regulators are junk (and I agree SOME of them are),

2: That the sedan is just a bad design, and

3: That the fur lined rubber window tracks lose their fur as they age and become high dynamic friction systems. (For those of you who don't know what dynamic friction is, it is the moving friction. Static friction is the friction that must be overcome in order to get the system moving. I am not trying to be condescending with any explanations, just want to make sure my terms aren't confusing to some).

I offer an alternate theory based on my several years of observation: Failure of window regulators in a cable/pulley/track system is due to extensive static friction during initial roll-down, not increased dynamic friction (though it is prudent to keep dynamic friction to a minimum). Also - poor quality window regulators do not have enough tension in the cables, and therefore slack can accumulate either in the main spool or near the pulleys. This can cause the cable to come off the pulley or spool and become wrapped around the motor drive spline.

Finding root cause of failure is my business. What I mean by that is that my profession to do so. I work for a major supplier to the aviation industry and my company counts on me to determine why $hit fails. Not blowing wind up my own azz, just trying to add some credence to my theory. I'm not just some joker off the street with a theory, though there are plenty of people off the street with good knowledge and significant things to offer, just as there are plenty of professionals that don't know squat.

My observations that led me to this conclusion are both direct observation, as well as comments from people on this forum.

Let's start with my first observation: when I roll my windows down after not doing so for a while (days), there is a significant "pop" as the static friction breaks loose, as if the window was glued in place at the upper rubber seal and the motor had to break it free. Also if I roll my windows back up and do it again, no "pop." So let's think about what happens when the window is stuck due to high static friction and we roll it down. The first thing is the motor moves but the window doesn't. This is possible because of the spring loaded tensioners in the cable system. The next thing that happens is the springs compress then bottom out which gives the motor drive the ability to overcome the static friction of the top window/seal area and the window breaks free. Suddenly the spring and all the tension in the system releases which can result in slack in the cable briefly. Depending on where the cable slack ends up can determine if the unit fails or not (cable jumping off the pulleys or spool). The last three regulator failures that I have had are because the cable jumped its spool (the thing the motor engages to, a nylon spool that the cable wraps around). The cable then becomes wrapped around the motor drive spline and boom: the system binds up and stops. All of my failures occur when I roll the window down, it sounds slow, then when I go to roll them up it binds and stops. I have noticed that some of the cheap aftermarket units (Hamburg Technic for one) have a significant gap between the spool and the galvanized steel plate (see next picture) which is undesirable as it does not contain the briefly loose cable as good as one with no gap or a small gap. This allows room for the cable to come out of its enclosure. The latest one I put in was a Uro Premium and it seems to be much better in that area with little to no gap. The Uro Premium is the one with ball bearings to reduce dynamic friction, but this isn't why I bought it. I bought it because of the warranty and because the gap looked to be much smaller in the picture (and I can verify that it is significantly smaller, see the second picture below). I have since learned that the design concept for the ball bearing was so that the cable can be tighter to help to keep the cables from jumping the pulleys and spool, and that the pulley design has a deeper groove to keep the cable from jumping off. This in itself are good changes, but have not led to a failure free design as you will read later in this thread.There has been two iterations of the Uro Premium Regulator, the first had tighter cables but still had some failures, the second the cables were tightened more... we will see if they hold up. These features are probably what sets the OE regulators apart from the aftermarket ones. Hopefully the newest iteration of the Uro Premium can perform like the OE unit, if not I will be switching to OE next go-around.

Hamburg Technic:
<a href="http://s1090.photobucket.com/user/yewzer/media/bad%20gap%20reg.jpg.html" target="_blank"><img src="http://i1090.photobucket.com/albums/i370/yewzer/bad%20gap%20reg.jpg" border="0" alt="Hamburg Technic photo bad gap reg.jpg"/></a>

Uro Premium:
<a href="http://s1090.photobucket.com/user/yewzer/media/good%20gap%20reg.jpg.html" target="_blank"><img src="http://i1090.photobucket.com/albums/i370/yewzer/good%20gap%20reg.jpg" border="0" alt="Uro Premium photo good gap reg.jpg"/></a>

My second observation involves why coupe's and verts suffer far less from this problem. My theory is two-fold. 1, the rubber seal may be different (I don't have a coupe handy to look at closely) and not as tight. (and I have learned that the whole regulator and track system is very different) 2, the coupe (and vert) roll the windows down slightly every time you open the door. This along with opening the door breaks the static friction daily while it is low, and doesn't give it days to allow the window to adhere to the rubber seal.

My third observation is that I have window tint. The window tint is cut very high on the glass which allows the tint material to go into the window seal area. I believe this window tint material makes the static friction issue worse. I am even more convinced of this after a couple of weeks with them trimmed down as outlined later in this post.

So what can we do about it...? I don't know all the answers but I have some ideas.

The first thing I did was cut the window tint down lower on the glass so it is outside of the seal, which I have done very recently (about 2-3 days before I started this thread). This can be done at a height that will not allow light in the top when closed but low enough to keep it out of the seal. What I did is use the witness mark from the seal on the window tint and cut a few mm's below that. If you are a perfectionist don't do this yourself, it is very difficult to get that line straight and clean on a fully cured tint. I will need new tint sometime soon so I took a chance in order to perform this test. The glass on the top edge of the window needs to be clean and free of any build-up. I think the build-up that I had was residue from window tint adhesive and plain and simple grime. When I say build-up I'm not talking about a giant glob of goo, just a thin line of something right where the window seal touches on the inside of the window. See the next two pictures for before and after cutting the tint down. When I get new tint I will request the tint be cut to a specific spot as well.

Tint before cutting. Note that you can see the build up, or witness mark where the window curves down (sorry for the bad pics):
<a href="http://s1090.photobucket.com/user/yewzer/media/tint%20before%20cut.jpg.html" target="_blank"><img src="http://i1090.photobucket.com/albums/i370/yewzer/tint%20before%20cut.jpg" border="0" alt="Tint Before Cut photo tint before cut.jpg"/></a>

Tint after cutting:
<a href="http://s1090.photobucket.com/user/yewzer/media/tint%20after%20cut.jpg.html" target="_blank"><img src="http://i1090.photobucket.com/albums/i370/yewzer/tint%20after%20cut.jpg" border="0" alt="Tint After Cut photo tint after cut.jpg"/></a>

Third the top seal of the windows must be lubricated and cleaned to keep them from becoming sticky. B'laster the Dry Lube is the best we have found. Shin Etsu Grease can be used in the rubber tracks on the sides of the windows.

I did all of these steps to my windows only a few days ago and so far the pop noise is greatly reduced. And still is a few months later

This thread is not intended to be a final answer, but a living document that I will update from time-to-time. At the moment, I have a new regulator in the driver door, and regulators that are about 1-2 years old in the driver rear and passenger front doors, and an unknown in the passenger rear. My intent is to keep the static friction to a minimum through cleaning and regular conditioning of the rubber seal (probably every time I wash my car) and see how long I can make the regulators last.

Wish me luck and bump this thread if you are wondering if my regulators are holding up.

Feedback, alternate theories, rubber conditioner tips, "duh," and middle fingers welcome. :thumbsup:

Future additions to this original post will be in post number 190 as there is a limited number of edits one can do
 

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I agree that the coupes and convertibles have far fewer problems and likely fewer possibilities for problems.

I have 2 convertibles, a 2006 E46 330cic and a 2003 VW Beetle.

Both cars drop the glass each time the door is opened. The VW has updated window regulators that actually drop the window with the keyfob, but will also drop the window with the door pull.

Addition the convertible and coupe windows are much longer/larger and heavier.

The coupe and convertible windows DO NOT have fur lined guide gaskets. Typically the coupe and convertible windows have 1 or 2 guide rods inside the door that the glass glides on. So the heavier glass, the lack of fur lined guide gaskets and the fact the glass drops every time the door is opened are probably the main reasons these window regulator hold up better. I also think the coupe and convertible window regulators are more robust for the heavier glass and the fact the windows get a lot of side to side tweaking when people open and close the door by the glass rather than the door.

But also for the record, it is not just BMW window regulators that are problems. Honda and GM have issues as well. Many of these have the cable and pulley system and the plastic pulleys crack and break. Often the problem is with the rear windows because they are not used often enough. As you said, part of the problem may be the glass sticking to the gasket over time, the other part is the pastic pulleys get stressed and sometimes crack from the tension of the cable.

I also just today replaced the plastic slides with rollers in a rear window on my sons 1996 Impala SS. The original nylon/plastic slide were kind of a rectangular shape, for some reason these break quite often, not sure if the problem is age or the design. I replaced the rectangular slides with round wheels, very easy to just press the ball of the window regulator into the new wheel.

As for the gaskets sticking, for years I have been using spray silicon that does not have petroleum in it. For example the Gunk/Liquid Wrench silicon spray smells like it has petroleum in it. Also a product called Gigaloo which seems to be very much like a silicon spray.

I spray a paper towel or rag down with the silicon and while the gaskets until they are clean and lubed. Then I spray the fur lined window channels down a as well. Also agree about keeping the top edge of the window clean, seems that there is always crud building up on the top edge of the glass.

So far I have not had any window regulators fail in any of my cars other than the '96 Impala SS, but we are talking about a 20 year old car. Hell the original Urethane front sway bar end link bushings just slit and cracked. I just replaced them because they were hard and brittle, but after 20 years, what do you expect!

Hopefully some forum members can chime in and add pictures of their failed window regulators. Please also include the regulator age, vendor name, where you are located, if the car is garaged and if it is a daily driver or a seasonal garage queen. I assume most Sedans and Touring will be daily drivers or maybe put away during the Winter in some locations.

This may help others figure out what regulators will fail quickly, which regulators to avoid and what PM steps have been taken on Sedan and Touring windows. This way we can all learn what steps other members take, what products they use and what actually seems to extend the life of the regulators.
 

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I agree with your observations.
I have a sedan and have been through many regulators...mostly fronts because I rarely lower the back windows. I was going through so many that I have become an expert in changing them out.
My car also made the same 'pop' from a gummed up top of the window.

About 2 years ago I was getting ready to go on a trip and loading up my car when I accidently ripped the tint on one of my windows. Since I didn't think I had time to make an appointment to have the window re-done I figured I'd just take off all my tint. (Big mistake! But that's a story for another thread)

When taking the tint off I noticed how much the tint had 'shrunk' (Cheap tint?) and it was almost like sticky glue along the top edge.
Long story short...since removing the tint and keeping the top edge clean I haven't had any more failures and the pop is very minimized.

Edit: Florida car, always outside in the heat, 2 vehicles 1 driver.
 

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Discussion Starter #4
...since removing the tint and keeping the top edge clean I haven't had any more failures and the pop is very minimized.

That's encouraging. By the way, I have found that 409 dissolves the tint adhesive that is left behind after removal.

Thanks for your (and jfoj) reply.
 

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That's encouraging. By the way, I have found that 409 dissolves the tint adhesive that is left behind after removal.

Thanks for your (and jfoj) reply.
Now you tell me!!!:bawling:

I used razor blades and lots of window cleaner.
(And trust me, removing tint isn't something I ever want to do again!)

EDIT: I just noticed someone over in the DIY section that tried one of the new URO 'premium' regulators just had one of those fail after less than a month.
 

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Just to add, the convertible (and by extension the coupe because they share the same part) have more robust regulators because they have windows that are meant for cantilevered operation.

I cruise regularly on the freeway going 90 with the top down and the windows up to cut down on noise and the windows are incredibly stable considering the lateral load and vibrations they're subjected to. Potholes rough them up too with the inherent side to side motion but they hold up well.
 

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Discussion Starter #7
EDIT: I just noticed someone over in the DIY section that tried one of the new URO 'premium' regulators just had one of those fail after less than a month.

Did they mention how it failed? Link?

If the sticking glass is the problem the ball bearings won't help, but I was hoping the gap issue would.
 

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Every one of my sedan windows make a pop noise which sounds like the window is sticking to the rubber, just as you mentioned. I also have a suspicion that this continuous pop and friction has somehow loosened the bolts holding the window and that's why they rattle going over a bump. I plan on tightening the bolts, but at this point my window regulators have not failed YET. The car has 127k on it and I've only had it for about 9 months so I'm not sure if they had been replaced before or not.
 

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Completely agree. The place that did my window tint had to refund me to cover a new regulator. They have tools to slide between the window and seal after the adhesive has dried to keep that very thing from happening on all cars. They never used it on mine and sure enough the cable popped off and got wound up around the motor.
 

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Good to know the coupes/convertibles have less issues (to be selfish since I have a coupe).

Regarding this point of the OP's "2, the coupe (and vert) roll the windows down slightly every time you open the door. This breaks the static friction daily while it is low, and doesn’t give it days to allow the window to adhere to the rubber seal" I don't drive my car everyday so I don't know about static friction in my situation. Sometimes I just drive once or twice a week and sometimes it can sit for a week. Then sometimes I drive everyday for a week. This daily lowering of the friction seems like a valid point to me but I just thought I would toss that out for discussion.

I use Aero 303 on the gasket and I keep the windows clean. I am almost certain that I have read on this forum that clean windows make things easier on the regulators and this would be consistent with the issue caused by window tint.

I am not sure if this helps, but unless I am going to drive around with the windows/sunroof open I do not lower it all the way when I am talking to someone or swiping the card at the gate going to my parents. Or, when I used to eat fast food I also wouldn't lower it all of the way.

The original owner of my car had the dealer resecure the cable to the regulator and had them replace the cable holder in January 2006 at 28,000 miles. No issues since that time.

I have never had a regulator issue on either 330Ci and the first one did have tint. Both sat outside all the time.

Great original post.
 

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Now you tell me!!!:bawling:

I used razor blades and lots of window cleaner.
(And trust me, removing tint isn't something I ever want to do again!)

EDIT: I just noticed someone over in the DIY section that tried one of the new URO 'premium' regulators just had one of those fail after less than a month.
Get a heat gun. They are cheap, and they are great for all manner of sticker removal.
 

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I agree with your observations.
I have a sedan and have been through many regulators...mostly fronts because I rarely lower the back windows. I was going through so many that I have become an expert in changing them out.
My car also made the same 'pop' from a gummed up top of the window.

About 2 years ago I was getting ready to go on a trip and loading up my car when I accidently ripped the tint on one of my windows. Since I didn't think I had time to make an appointment to have the window re-done I figured I'd just take off all my tint. (Big mistake! But that's a story for another thread)

When taking the tint off I noticed how much the tint had 'shrunk' (Cheap tint?) and it was almost like sticky glue along the top edge.
Long story short...since removing the tint and keeping the top edge clean I haven't had any more failures and the pop is very minimized.

Edit: Florida car, always outside in the heat, 2 vehicles 1 driver.

This will make you feel worse. I've used this method myself and on friends cars.

http://www.youtube.com/watch?v=GC3Y1wuB3VY&sns=em

Steamer for the win ;)
 

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Discussion Starter #16
My driver side window made that 'pop' noise this weekend after opening it from sitting in the sun after a thunder storm. The regulator is on its way out. That's 2 regulators I will soon need to replace :(.

To be clear, I think the pop sound is the stuck window not a failing regulator. The source of the pop sound is what is causing the failure.
 

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