Does anyone know if there is common leak on a 96 Bonneville that will cause water leak in the trunk. I had the back glass tested and nothing was found. Trunk seal seems to be fine. Anything else?
The modern brushless car washes have powerful water sprays that go SIDEWAYS against the car. My wife’s car has a trunk lid that has an exposed seal, which is no problem in the rain, but lets water in when using this water pressure car wash.
I would start by checking the seal around the trunk lid and then washing the car carefuly by hand and see what happens.
Also check under the trunk mat and in the wheel wells if there are any wet or rust spots indicating water is finding its way up from the road spray.
This is not water coming from the wheel well. I REALLY noticed it after we had a very long rain. So much water…it filled the spare tire area and overflowed into the rear floor board.
Sunroof? if so check the drains.
Tail lights are another possibility.
Fuel fill area?
How claustrophobic are you? I once solved a problem like this by taking a flashlight, crawling in to the trunk with the lid closed, and having an “assistant” blast the trunk area with a garden hose. The perimeter seal was fine, but the seal around one of the tail lights was not. The aerodynamics of the car were such that water was forced in around the tail light and trickled covertly in to the spare tire well.
Edit: Looks like mcparadise suggests tail lights, too!
I have already had one of the tail lights fixed…getting inside is my next thing to do. Someone suggested maybe around the spoiler holes. Does the fuel fill lead into the truck though?
It might, just depends on the car. Usually it does but I think most auto makers put it behind a wall.
I have solved a few of these. As Mr_Josh noted, I often had to resort to getting someone with a flashlight to get inside the trunk while a 2nd person sprayed the car/trunk/window with a hose. Doing it that way never failed me.