Z3 Solution Window Blanket

Pros: Works much better than the BMW window blanket. On new cars it will prevent formation of the dreaded wave. On older cars it helps prolong rear window life.
Cons: Slightly bulkier than the BMW version. Not free.
Cost: $37.95 from Z3Solution

This article reviews the Z3 Solution alternative to the free BMW window blanket. The Z3 Solution product has been designed to minimize or eliminate the dreaded “wave” whcih forms when you leave the top down on your Z3. It does this by providing extra padding in critical areas. The blanket sells for $37.95 from Z3 Solution.

I’ll preface this article with a couple of comments:

* If you are leasing your Z3 and you plan on turning it back in, this article is probably not for you.

* If you plan on keeping your Z3 for a couple of years and are worried about it looking good, especially for resale, this is one of the products you should seriously consider.

The picture above shows two window-blankets. The one of the top is the Z3 Solution version, The one on the bottom is the standard BMW version. They are both made of just about the same type of flannel material, the BMW version is gray, the Z3 Solution version is beige. You can see from the picture that the Z3 Solution version is a bit smaller than the BMW version. There is one critical difference between the two of them: The blanket on the top can prevent the dreaded “wave” in the Z3 plastic windows.

The wave is the effect you see when you put your top down for an extended period of time. When you put the roof back up there is a slight wave which goes horizontally across the window. It’s caused by one of the roof supports hitting the window and creating pressure. Since the Z3 first came out, people have been trying to get rid of the wave by stuffing various things into the fold of the roof. There used to be round pillows you could buy and many people also used pipe insullation material in an attempt to get rid of the wave. None of these approaches worked very well.

Keith, of Z3 Solution, studied the folding of his roof and determined that many of the earlier attempts to combat the wave were really addressing the wrong part of the window. The actual culprit is not the place where the window folds, instead he determined that the second support from the back actually rubs along the window with a lot of pressure creating both the wave and the associated scratch marks.

Keith determined that some padding in the window blanket would be the perfect way to protect the window from the damage caused by the roof support. The problem was that padding the whole thing would mean that the blanket would be bulky in areas where the bulk wasn’t needed. The first think Keith did was to cut down the size of the blanket to just the critical window area. In this way the padded blanket places no extra strain on the roof which might lead to premature wear. The next thing was to pad only the lower two thirds of the blanket, eliminating the bulk at the critical bend in the window.

Keith was also concerned about the quality of the unit. He tested out various materials to simulate the BMW quality. The result is a product which might have come from BMW. Keith uses the same quality fabric, the same connectors and the same quality of fit and finish as the BMW unit. The only obvious difference is the longer loops on the BMW I mentioned that the longer loops and slightly shorter elastics on the BMW model do make it easier to handle and Keith said he would look into addressing this in production versions of the blanket. I have a ’97 2.8 with a hard top. In the fall I had the soft-top completely replaced by BMW, so I got a new window. The window has spent the winter crushed under the hard top, so when I took the top off for the spring I had a significant wave. Keith told me that the Z3 Solution blanket will not remove the wave, but it would keep newer cars from acquiring one. Based on experience, I have found if you hit the window with a hairdryer it will straighten out the plastic.

In several weeks of use, the blanket has practically eliminated the wave from my window. I’m very impressed and would recommend this highly to anyone who intends on keeping their car for a while. Using the Z3 Solution window blanket will definately prolong the life of your rear window and give you a much clearer view. With window replacement running anywhere from $150 and up, the $37.95 Z3 Solution Blanket seems like cheap insurance against a hefty repair bill.

HMS Window Blanket for BMW Convertibles

Pros: Provides additional protection for the delicate and expensive rear plastic window.
Cons: Harder to fold and store because of the bulkier design
Cost: 39.95

BMW created a device we owners quickly named the “window blanket”, it was a simple yet functional blanket that draped across the rear window and protected the window from scratches when the top was folded down. But the one thing the BMW blanket didn’t do was stop the window from creasing when the rear window folded incorrectly (with a wrinkle). HMS improved the BMW design and took it one step further by adding a bulky area to middle of the blanket which makes the window fold in a more rounded way in order to keep the window from creasing. It also appears HMS used a heavier fabric so there is some additional padding associated for the entire area that the blanket covers.

The bulky area appears to be filled with beans or something similar. The added weight from this bulky area forces the top to fold correctly and keeps it from folding to sharply (which can cause creasing). The improved design works better than the original design in protecting the top from these creases but there are some trade-offs. The HMS design is harder to fold and store because of the extra padding. The padded area is divided into three sections so folding it width wise is limited to three three sections. With the original BMW blanket I kept it tightly folded up and stored in one of the pockets of the trunk organizer. However with the bulkier HMS design this was no longer possible. I end up rolling it lengthwise and laying it in the area behind the center console. This might actually be a better location since it helps remind me to use the blanket when I want to put the top down.

I’m trying to get in the habit of using the boot cover and HMS blanket more often since I was starting to see some wear and tear on the plastic window. For this reason I like the HMS blanket more so than the BMW blanket. It keeps the top folded correctly and provides additional protection for the delicate and expensive rear plastic window.

Sold By:

HMS Motorsport


(888) HMS-3BMW

Cleaning the Plastic Rear Window

To say my rear window was dirty was an understatement. Honestly, I can’t remember ever washing it in the time I’ve owned the MZ3. It had gotten to the point that rear visibility, especially with the windscreen, was zero. With the homecoming approaching, I figured it was time to clean this window. Turned out to also be a good time to try out the Meguiar’s window cleaner and polish to see just how good this stuff is.

In the graphic below, the top picture is of the window before I did anything (except remove the windscreen). The middle picture is after I used Meguiar’s #17 Clear Plastic Cleaner on both the inside and the outside. The cleaner was difficult to use, especially on the inside. This stuff coats on then dries to a paste just like car wax does. Rubbing off that dried pasty/wax was difficult especially when trying to work on the inside of the window. It took me about 30 minutes but the results were simply amazing. Except for a harsh black line of buildup in a fold mark, it removed everything.

The next step was to use the Meguiar’s #10 Clear Plastic Polish, I had already decided I was not going to mess with the inside window since my back was aching from the cleaner. But honestly it wouldn’t have been very hard since the polish doesn’t dry to a paste like the cleaner. The polish took the buildup in the fold line off with very little effort. The very bottom picture in the graphic below was after the cleaner and the polish. Looks like a practically brand new window as far as I am concerned. I’m very pleased with the Meguiar’s cleaner and polish, however I think I’ll clean and polish the window a little more regularly from now on.

I’ve seen BMW dealerships sell some of the Meguiar’s products in their parts department. But if you are having a hard time finding them you can always purchase directly from Meguiar’s. Meguiar’s has a web site with a dealer locator, but you have to call the number below to actually place an order.

To Order Call: 1 (800) 545 3321

Fax: 1 (949) 752-6659

Or Write: 17991 Mitchell South, Irvine, CA 92614