New problem - help!
06-13-2008, 08:04 AM
#1
Racer
Thread Starter
New problem - help!
Hello everyone, would be grateful for your thoughts on the following:
my windscreen creaks like mad and having tried all the usual fixes of ice wax, teflon tape, rubber cord, I finally decided to replace the rubber seal with a new one and apply the compound Porsche recommends in a TSB. I removed the old seal which did not come out easily, but required some pulling and cutting. Anyway, having removed it and cleaned the channel in the windscreen surround, I taped off the body and screen and applied the mastic. I left it to dry overnight and fitted the new rubber seal. All went well except the seal was a bugger to fit as it kept falling into the mastic which has the consistency (and stickiness) of hot bubblegum. So having fitted it I drove up the road and turned the radio down with some trepidation. Still creaking but now I'm sure it's the back screen. Now to my problem, when I drive at over 40mph the front screen now "howls". I have checked the screen rubber, ensured that it's fully seated in the channel but it still sounds like it's not seated. Any clues? Its driving me nuts and I hate it when I end up worse than I started out!
Any help would be much appreciated!
my windscreen creaks like mad and having tried all the usual fixes of ice wax, teflon tape, rubber cord, I finally decided to replace the rubber seal with a new one and apply the compound Porsche recommends in a TSB. I removed the old seal which did not come out easily, but required some pulling and cutting. Anyway, having removed it and cleaned the channel in the windscreen surround, I taped off the body and screen and applied the mastic. I left it to dry overnight and fitted the new rubber seal. All went well except the seal was a bugger to fit as it kept falling into the mastic which has the consistency (and stickiness) of hot bubblegum. So having fitted it I drove up the road and turned the radio down with some trepidation. Still creaking but now I'm sure it's the back screen. Now to my problem, when I drive at over 40mph the front screen now "howls". I have checked the screen rubber, ensured that it's fully seated in the channel but it still sounds like it's not seated. Any clues? Its driving me nuts and I hate it when I end up worse than I started out!
Any help would be much appreciated!
06-13-2008, 08:57 AM
#2
Rennlist Member
In all probability there is a small gap causing the howling. It doesn't take much of a gap at all to produce wind noise at 40 MPH (Think about how much noise you can make lightly blowing across the top of a beer bottle).
First, be sure the gasket is seated properly around the glass and that the edges are seated smoothly against the bodywork and not protruding in a manner that would interfere with airflow and cause the howling. If the gasket is properly seating then, there are two possible causes:
1. There is a gap somewhere that you can't easily see that is quiet at low speeds, becoming noisy only when your speed reaches a certain point (More likely).
or
2. Everything may look fine when the car is stationary, but then "flex" or "give" when the car gets to a certain speed, thus opening a small gap that causes the howling (Less likely).
You can locate the gap by:
1. Smoothly taping all the way around the windshield where the gasket meets the body.
2. Drive the car and determine if the howling is gone. If it is, then you know the gap is around the outside edge of the gasket.
3. If you drive the car and the howling continues, proceed to tape the area where the gasket meets the windshield and drive again to confirm that the howling is gone, thus indicating a gap where the glass fits the gasket.
4. Assuming that taping eliminates the howling, , sucessively remove short sections of tape, driving between each removal until the howling returns, thus indicating the area where the gap is.
I have to be honest here and say that if, at the point where I have taped the entire perimeter of the windshield, the howling continues, I would take the car to a shop and let them deal with it.
I hope this is useful.
Terry
First, be sure the gasket is seated properly around the glass and that the edges are seated smoothly against the bodywork and not protruding in a manner that would interfere with airflow and cause the howling. If the gasket is properly seating then, there are two possible causes:
1. There is a gap somewhere that you can't easily see that is quiet at low speeds, becoming noisy only when your speed reaches a certain point (More likely).
or
2. Everything may look fine when the car is stationary, but then "flex" or "give" when the car gets to a certain speed, thus opening a small gap that causes the howling (Less likely).
You can locate the gap by:
1. Smoothly taping all the way around the windshield where the gasket meets the body.
2. Drive the car and determine if the howling is gone. If it is, then you know the gap is around the outside edge of the gasket.
3. If you drive the car and the howling continues, proceed to tape the area where the gasket meets the windshield and drive again to confirm that the howling is gone, thus indicating a gap where the glass fits the gasket.
4. Assuming that taping eliminates the howling, , sucessively remove short sections of tape, driving between each removal until the howling returns, thus indicating the area where the gap is.
I have to be honest here and say that if, at the point where I have taped the entire perimeter of the windshield, the howling continues, I would take the car to a shop and let them deal with it.
I hope this is useful.
Terry
06-13-2008, 01:38 PM
#3
Racer
Thread Starter
Thanks Terry,
Sounds like a plan. Hopefully the first round of taping will indicate where the leak is otherwise I'm in danger of lots of speeding as most of the roads around here have 30 mph speed limits. Still gives me an excuse to drive around with no particular place to go.
Many thanks
Tal
Sounds like a plan. Hopefully the first round of taping will indicate where the leak is otherwise I'm in danger of lots of speeding as most of the roads around here have 30 mph speed limits. Still gives me an excuse to drive around with no particular place to go.
Many thanks
Tal