r53matt
Member
Hey guys,
After a long, enduring search for what was causing my passenger floorboard sound insulation mat (underneath carpet) to get wet, I have finally located the leak.
This is what the leak looked like:
I initially started my search by completely re-doing my sunroof drains (when I had my headliner redone). Definitely solved the sunroof drain issue, but my passenger floor pan was still collecting water from somewhere. I eventually took out the carpet and sound deadening mat and did several water tests. Flooding just the "undercowl" area (where the cabin air filter, ECU, wiper motors are), I could not get it to leak - I also cleaned this area pretty well and ensured the side exit drains were not clogged with leaves and mice nests. This told me that my cabin air filter housing was not the culprit (which I understood to be a common issue). However, when I would douse the lower passenger side of the windshield with water, I could get a water stream to run down the inside of my firewall, where it would collect in the floor pan. This initially led me to believe perhaps a leak was coming from underneath the windshield, through the glue... So I had the windshield replaced. When the tech had the windshield removed from the car, I did a few more water tests, squirting water around that area of the body (where the windshield glue adheres to) and needless to say, the water streams from this test were not consistent with the water stream down the firewall that I was searching for. Here's what windshield glue area I tested looked like:
Ok, so back to the drawing board...
I spent more time dousing the windshield with water and attempting to follow its path from outside the car to inside. Well, eventually I noticed that water, when sprayed hard enough, or during a heavy rain, would run down the side of the engine bay and collect on the rear side of the strut tower. Here's a pic showing you the path:
And obviously, rain can get into this area just by coming through the gap between the hood and the fender. But the important thing happening here is that water is running behind the top of the strut, and from there it runs down the engine-side of the fire wall. I've pulled the fire wall insulation mat (engine bay side) away from the firewall and can see the wetness, and what appears to be some degrading butyl cord seal. The part number of the fire wall is 1J1721039AF and the ErWin repair manual refers to it as the Engine Compartment Partition Panel. Looking at how the firewall is fastened to the body (with a butyl cord seal in between), I can see exactly how this could develop into a leak like what I'm seeing. Additionally, I ran water directly behind the top of the strut, ensuring all of it ran down the engine side of the firewall and voila, leaks inside just as I expect.
So, the leak must either be coming from the firewall seal, or perhaps a firewall bolt.
How would you guys go about attempting to stop this leak? I've considered an RTV dam around the strut tower to keep water from even having the chance to flow back to the firewall (but this would just look tacky), to adding some RTV to the fire wall, etc. Problem is, it's a bit of a PITA to get your hands back there, especially with the insulation mat in the way. Thanks for the thoughts!
After a long, enduring search for what was causing my passenger floorboard sound insulation mat (underneath carpet) to get wet, I have finally located the leak.
This is what the leak looked like:
I initially started my search by completely re-doing my sunroof drains (when I had my headliner redone). Definitely solved the sunroof drain issue, but my passenger floor pan was still collecting water from somewhere. I eventually took out the carpet and sound deadening mat and did several water tests. Flooding just the "undercowl" area (where the cabin air filter, ECU, wiper motors are), I could not get it to leak - I also cleaned this area pretty well and ensured the side exit drains were not clogged with leaves and mice nests. This told me that my cabin air filter housing was not the culprit (which I understood to be a common issue). However, when I would douse the lower passenger side of the windshield with water, I could get a water stream to run down the inside of my firewall, where it would collect in the floor pan. This initially led me to believe perhaps a leak was coming from underneath the windshield, through the glue... So I had the windshield replaced. When the tech had the windshield removed from the car, I did a few more water tests, squirting water around that area of the body (where the windshield glue adheres to) and needless to say, the water streams from this test were not consistent with the water stream down the firewall that I was searching for. Here's what windshield glue area I tested looked like:
Ok, so back to the drawing board...
I spent more time dousing the windshield with water and attempting to follow its path from outside the car to inside. Well, eventually I noticed that water, when sprayed hard enough, or during a heavy rain, would run down the side of the engine bay and collect on the rear side of the strut tower. Here's a pic showing you the path:
And obviously, rain can get into this area just by coming through the gap between the hood and the fender. But the important thing happening here is that water is running behind the top of the strut, and from there it runs down the engine-side of the fire wall. I've pulled the fire wall insulation mat (engine bay side) away from the firewall and can see the wetness, and what appears to be some degrading butyl cord seal. The part number of the fire wall is 1J1721039AF and the ErWin repair manual refers to it as the Engine Compartment Partition Panel. Looking at how the firewall is fastened to the body (with a butyl cord seal in between), I can see exactly how this could develop into a leak like what I'm seeing. Additionally, I ran water directly behind the top of the strut, ensuring all of it ran down the engine side of the firewall and voila, leaks inside just as I expect.
So, the leak must either be coming from the firewall seal, or perhaps a firewall bolt.
How would you guys go about attempting to stop this leak? I've considered an RTV dam around the strut tower to keep water from even having the chance to flow back to the firewall (but this would just look tacky), to adding some RTV to the fire wall, etc. Problem is, it's a bit of a PITA to get your hands back there, especially with the insulation mat in the way. Thanks for the thoughts!
That being said, I'm ready to stop needing to dry my sound insulation out every time it rains 