Water Ingress, Roof Alarms and Windscreen Bovva

[TeeMac]

I posted a wrap up on a thread I'd started previously regarding some recent problems I've had with water ingress. Unfortunately, both the wrap up and the original thread has disappeared off the blog altogether, which is a pity as there was (I hope) some worthwhile info in amongst my otherwise drivelling guff.

Anyway, here's a summary:

Got a low mileage 2011 35is recently to replace my E86, and shortly after noticed water sitting in the near-side storage compartment in the boot. Turns out the water was leaking in via the drainage channel between the body and the n/s rear light cluster. Issue was resolved by replacing the rear light cluster, which (after Dealership pressure) BMW accepted under the AUC warranty.

Shortly after, the car roof started whistling like a maniacal mynah bird at any speed over 40mph. Let's call that a pretty effective speed limiter...

Simultaneously, the car started intermittently giving a fault alarm for the roof closure. As the whistling only occured with the roof closed, and given the alarms, I figured it was an issue with the roof seals or the closing position of the roof.

Try as did, I couldn't sort the problem, and things turned shortly after for the worse when the roof sprung a leak above the windscreen, the water dripping along the interior roof moulding, and onto the dash/steering/seats.

Curiously, on checking it out there was no water sitting in the roof seals - both the vertical seal behind the windscreen at the roof line and the horizontal seal behind it were completely dry.

Further inspection found the problem to be the windscreen, and a problem I've never come across before in 30-odd years of driving: The windscreen was becoming unbonded from the frame along the top of the frame, directly above the rear view/rain sensor. Note, it was not delaminating, as can happen, but unbonding altogether from the frame.

Given the water seemed to pooling in the interior light cluster, I guessed that the roof alarm issue was being caused by water interferring with some roof sensor or another.

Turns out the alarm was being caused by an entirely unrelated failure of a microswitch in the folding mechanism in the boot.

The dealership (Park's) persuaded BMW to replace the windscreen (plus rain sensor unit) on Goodwill, while the microswitch was replaced under AUC. Neither the dealership nor BMW could explain how or why the windscreen would fail in such a manner, and given its safety-critical role, seems a topic worth sharing.

[Wondermike]

It was moved into E89 Problems

https://z4-forum.com/forum/viewforum.php?f=45

[TeeMac]

A-ha!

[greg1953]

I had a bonded windscreen leak on a Rover SD1 back in the '80s and on a Golf Mk5 4yrs ago.

[djstan]

I have had this very problem with my windscreen. BMW weren't interested in the slightest, which resulted in me having a massive rant at the guy on the phone, so I'm glad you got a better response than I did.

In the end, I paid Auto Windscreens to take the old windscreen out (carefully) and put back in again with new glue stuff - car never felt better! I'm still feeling very bitter that BMW didn't want to help at all....