eNate
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Joined: Mon Sep 09, 2019 5:33 pm

Windshield Wipers "Thumping" Windshield...

Thu Jan 16, 2020 10:08 pm

Any ideas on the cause / solution to this one?

While stopped or at slow speeds, the wipers make a thumping noise right as they begin the upward strike -- almost as if they were beginning lifted off the glass, and being dropped onto it.

This isn't the dry rubber dragging noise. It's a single, loud "Thump" each time.

I've been noticing this usually during intermittent operating, and it doesn't happen 100% of the time.

Once I begin moving at normal speeds, the noise goes away. It's definitely speed dependent.
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eNate
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Re: Windshield Wipers "Thumping" Windshield...

Mon Jan 27, 2020 7:55 pm

I haven't figured this one out yet and am wondering if I should proactively change my wiper blades before taking it to BMW to look at. The wiper blades don't have any obvious damage and they're giving me a clean wipe.

But poking around, I noticed that the outboard end of my long wiper blade dips below the windshield glass. It's just barely over the edge in the photos, but you can see from the dark area on the plastic that it continues another 3/4 inch. I don't know yet if this is the source of the thumping noise, or if this is normal. And even IF this is a factor, how/why is the noise related to vehicle speed? You can see from the wipe marks on the black plastic about how far below the glass this tip goes. Is there a "wiper park" position? Does yours do this?

Image


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MKH
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Re: Windshield Wipers "Thumping" Windshield...

Tue Jan 28, 2020 6:23 am

The end of my wiper in the wiper park position has an inch or more of glass remaining between the wiper end, and the black plastic. Wrong wiper size maybe? Mine are 30" and 21".
wiper 1.jpg
wiper 1.jpg (58.15 KiB) Viewed 1346 times
wiper 2.jpg
wiper 2.jpg (47.64 KiB) Viewed 1346 times
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

eNate
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Re: Windshield Wipers "Thumping" Windshield...

Tue Jan 28, 2020 9:03 am

Thanks for confirming this and sharing photos, Mark. My wiper blade is the correct length, so there must be an alignment issue with the arm.

I ought to try to for a way to replicate this noise using a spray bottle so I can demonstrate it to the service writer when I take it in.
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vreihen
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Re: Windshield Wipers "Thumping" Windshield...

Tue Jan 28, 2020 10:04 am

eNate wrote:
Mon Jan 27, 2020 7:55 pm
And even IF this is a factor, how/why is the noise related to vehicle speed?
The base of a windshield on most vehicles is a *high* pressure area. That's why manufacturers put the cabin air intakes there, and why the frunk fills up with leaves every autumn. The faster you go, the more wind force pushing the floppy/spineless blades down.....
2015 BMW i3 BEV, Giga World, Tech and Driving Assistant packages, 15K miles

eNate
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Re: Windshield Wipers "Thumping" Windshield...

Sun Mar 15, 2020 5:23 pm

As a follow-up to a follow-up that I didn't post in this thread...

In February, I took my i3 in for some warranty work (viewtopic.php?f=10&t=16665). One of my squawks was this wiper thumping problem.

The tech's response was "recommend replacing wiper blades." Honestly, my blades are fine, and that wouldn't have cause the issue I was experiencing. Plus, we're at the tail end of rainy season in California so I'd wait until next fall to install new blades.

Well... after an historically dry February we've finally had a few days of rain, and guess what? The thumping noise is gone.

What's also gone is the long wiper blade parking itself south of the windshield trim strip, as I showed in the photo I posted.

So what bugs me is it seems likely that the BMW tech did something to realign my wiper and address this complaint, but purposely didn't document it. Does that mean he just "applied some english" to the wiper arm as an "attitude adjustment," or was it something else? Any guesses?
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vreihen
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Re: Windshield Wipers "Thumping" Windshield...

Mon Mar 16, 2020 3:53 am

Maybe the i3 is smart enough to spring the wiper alignment forward for daylight savings time????? :lol:
2015 BMW i3 BEV, Giga World, Tech and Driving Assistant packages, 15K miles

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