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Stiff or Slow Window Fix

Almost every Miata will eventually develop windows that are difficult to wind up and down or travel very slowly if they are power windows. The usual fix is to remove the door panel and spray the cables and rollers with white lithium grease. Although this often provides some improvement, many people report it helping very little or not at all.

Because I’ve experienced the exact same symptoms, and eventually broke a cable end off a particularly stiff manual window, decided to try and figure out why this was happening to begin with.

The cause of those stiff windows is actually its travel through the upper channel in the “vent” window area (for those not old enough to remember vent windows, it’s the little triangular shaped window in the front of the door). While it doesn’t seem like that little channel could create slow or stiff windows, there is actually a logical reason why it happens.
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Everyone has noticed that when riding with the top down, there is a back draft of wind created, thus the development of windblockers. Well, that same back draft that is blowing your hair backwards (and isn’t that a great look) is also blowing dust and dirt directly into that little channel. Over time, it builds up on the felt in there, causing increased resistance to the window traveling through. Most people think the answer is to then spray the same white lithium grease into the channel. This gives very temporary relief and then the problem quickly returns, often worse than before. That’s because the spray grease attracts and holds dirt very quickly.

The good news is that this is one of easiest fixes ever for an inherent Miata problem. For years, Honda has used a grease called Shin-Etsu for lubricating rubber/felt/silicone parts with great success. I had previously used it on a very noisy targa top on a Corvette and figured it couldn’t hurt to try.

I paid $15.80 for the tube you see pictured which should last the normal Miata owner a lifetime. If you have some need to have multiple Miatas like me, you may need to replenish your supply every ten years.

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I first thoroughly cleaned that channel with a large q-tip (got about two dozen of them from my doctor) using denatured alcohol. Once all the old lithium grease and its imbedded gunk was gone, then applied a very light coat of the Shin-Etsu grease with the same large q-tip, distributing it evening throughout that channel. The improvement was immediate and dramatic and this on a car with power windows where I had already done the relay upgrade without the relays helping the speed at all.

It’s been six months of top down, bad weather, cold weather and even some snow thrown in for good measure and the windows continue to operate as new. On my one manual window car, I can roll the windows up with one finger now, much as I remember them when new.

I believe if you get in the habit of cleaning the channels and reapply the Shin-Etsu once a year, the incidence of broken cables and regulators will plummet. The cables become frayed because of constantly applying so much pressure to overcome the friction, same with regulators. Better one $15 tube of grease over a lifetime than several hundred dollars of cables/regulators. I believe it will also keep the switch on power windows from failing or burning the contacts because there won’t be the increased pull over the contacts from trying to overcome too much drag.

It’s also probably a good idea to periodically lube the cables and rollers themselves by removing the door panels and using your spray grease there, where the areas are protected from the wind and perform a much different function than the alignment channel. I’ve put this particular task on my 30,000 mile maintenance interval.