Pass Footwell leak/ Firewall cowl reseal

DJ3Guns

Member
Car
2015 QX70S
Name
DJ
We Purchased a 15 Qx70 Sport with 65k a few months ago on a suggestion from my stepson who is an Infiniti Shop Foreman. It is a great car and compliments our 370z convertible.
A few weeks ago it developed the Pass Footwell leak and I confirmed that it was the firewall cowl by duct taping the cowl to windshield junction and stopping the leak. Since I have never seen a definitive fix for the seal replacement I just figured out my own.
After taking the cowl off I looked at the smashed and wet seal and realized it looks alot like a foam backer rod used in construction.
20200322_112219_tn1.jpg
I then measured the slot that the glass fits in and it is approx 1/4" so I think there is something that will fit that groove that is better than foam backer...
20200322_112227_tn1.jpg
This is what I pulled out.
20200322_130602_tn1.jpg
I had some 3/8 foam weather strip that is auto and marine ready but I knew there was something better out there. So off to Lowes I went.
I've always been a fan of bulb seals as the put constant pressure on the sealing surface and I found this seal in rubber.
20200322_124943_tn1.jpg
It is bulb shaped but is a double bulb.
20200322_124955_tn1.jpg

I bet I can cut them apart and use just one part of it and it is just over 1/4".
20200322_125002(0)_tn1.jpg

Installing the seal was easy using a flat blade screw driver to push it in. Also it is a touch wide once it is started I pulled it, stretching it a bit and making it thinner. It went right in.

20200322_125440_tn1.jpg

Final shot if what it looks like at the end of the channel. I then cut it to just the right length.

20200322_125456_tn1.jpg

It works perfectly.
A little snug when pushing the cowl back onto the windshield but that's what I want.
And, I'm sure the seal is not one time use if you have to remove the cowl again. This rubber is way more resilient than the open cell oem foam rod.
Hope you all find this helpful. We won't have to worry if the car is left out int he pouring rain now.

Jenny Loves her Car since it's really like driving her 370z in suv format.....
Resized_20191114_153408.jpeg
 
Last edited:
Very informative and instructive; thanks for sharing it with the group as it is an area I will keep an eye on as the car gets older.
 
We Purchased a 15 Qx70 Sport with 65k a few months ago on a suggestion from my stepson who is an Infiniti Shop Foreman. It is a great car and compliments our 370z convertible.
A few weeks ago it developed the Pass Footwell leak and I confirmed that it was the firewall cowl by duct taping the cowl to windshield junction and stopping the leak. Since I have never seen a definitive fix for the seal replacement I just figured out my own.
After taking the cowl off I looked at the smashed and wet seal and realized it looks alot like a foam backer rod used in construction.
View attachment 604930
I then measured the slot that the glass fits in and it is approx 1/4" so I think there is something that will fit that groove that is better than foam backer...
View attachment 604931
This is what I pulled out.
View attachment 604939
I had some 3/8 foam weather strip that is auto and marine ready but I knew there was something better out there. So off to Lowes I went.
I've always been a fan of bulb seals as the put constant pressure on the sealing surface and I found this seal in rubber.
View attachment 604934
It is bulb shaped but is a double bulb.
View attachment 604935

I bet I can cut them apart and use just one part of it and it is just over 1/4".
View attachment 604936

Installing the seal was easy using a flat blade screw driver to push it in. Also it is a touch wide once it is started I pulled it, stretching it a bit and making it thinner. It went right in.

View attachment 604937

Final shot if what it looks like at the end of the channel. I then cut it to just the right length.

View attachment 604938

It works perfectly.
A little snug when pushing the cowl back onto the windshield but that's what I want.
And, I'm sure the seal is not one time use if you have to remove the cowl again. This rubber is way more resilient than the open cell oem foam rod.
Hope you all find this helpful. We won't have to worry if the car is left out int he pouring rain now.

Jenny Loves her Car since it's really like driving her 370z in suv format.....
View attachment 604940
How do you get the cowl off ?
 
Its held in with a bunch of plastic push pins. remove the battery cover then the cowl on that side.

Update: It's been a year now and not a drop of leakage.
 
My hero! Luckily someone else posted this in my blower motor thread. Question, when you did the duct tape test, was that with a bucket / water hose or you left it on for a while while driving?

I have a passenger footwall small water intrusion but I cant recreate it. I only find out by the surprise of shorted electronics like my blower motor and illumination control module =/
 
Left the tape on and drove it in the rain plus left it outside all night in the rain.
 
Hey dj when you did this fix did you do anything for the bits on the underside of the cowl that press against the top of the fender and where the split point is?
 
We Purchased a 15 Qx70 Sport with 65k a few months ago on a suggestion from my stepson who is an Infiniti Shop Foreman. It is a great car and compliments our 370z convertible.
A few weeks ago it developed the Pass Footwell leak and I confirmed that it was the firewall cowl by duct taping the cowl to windshield junction and stopping the leak. Since I have never seen a definitive fix for the seal replacement I just figured out my own.
After taking the cowl off I looked at the smashed and wet seal and realized it looks alot like a foam backer rod used in construction.
View attachment 604930
I then measured the slot that the glass fits in and it is approx 1/4" so I think there is something that will fit that groove that is better than foam backer...
View attachment 604931
This is what I pulled out.
View attachment 604939
I had some 3/8 foam weather strip that is auto and marine ready but I knew there was something better out there. So off to Lowes I went.
I've always been a fan of bulb seals as the put constant pressure on the sealing surface and I found this seal in rubber.
View attachment 604934
It is bulb shaped but is a double bulb.
View attachment 604935

I bet I can cut them apart and use just one part of it and it is just over 1/4".
View attachment 604936

Installing the seal was easy using a flat blade screw driver to push it in. Also it is a touch wide once it is started I pulled it, stretching it a bit and making it thinner. It went right in.

View attachment 604937

Final shot if what it looks like at the end of the channel. I then cut it to just the right length.

View attachment 604938

It works perfectly.
A little snug when pushing the cowl back onto the windshield but that's what I want.
And, I'm sure the seal is not one time use if you have to remove the cowl again. This rubber is way more resilient than the open cell oem foam rod.
Hope you all find this helpful. We won't have to worry if the car is left out int he pouring rain now.

Jenny Loves her Car since it's really like driving her 370z in suv format.....
View attachment 604940
Great write up, my 2015 QX50 has developed a wisling noise and I have isolated it to be the front cowl, apparently Infinite does not sell just the piece an open cell fome they want the whole front cowl for approx $800 Canadian. And I have found your write-up that will definitively not cost me $800 Canadian roupies. Again Thank you, you saved my sanity from going crazy.
 
We Purchased a 15 Qx70 Sport with 65k a few months ago on a suggestion from my stepson who is an Infiniti Shop Foreman. It is a great car and compliments our 370z convertible.
A few weeks ago it developed the Pass Footwell leak and I confirmed that it was the firewall cowl by duct taping the cowl to windshield junction and stopping the leak. Since I have never seen a definitive fix for the seal replacement I just figured out my own.
After taking the cowl off I looked at the smashed and wet seal and realized it looks alot like a foam backer rod used in construction.
View attachment 604930
I then measured the slot that the glass fits in and it is approx 1/4" so I think there is something that will fit that groove that is better than foam backer...
View attachment 604931
This is what I pulled out.
View attachment 604939
I had some 3/8 foam weather strip that is auto and marine ready but I knew there was something better out there. So off to Lowes I went.
I've always been a fan of bulb seals as the put constant pressure on the sealing surface and I found this seal in rubber.
View attachment 604934
It is bulb shaped but is a double bulb.
View attachment 604935

I bet I can cut them apart and use just one part of it and it is just over 1/4".
View attachment 604936

Installing the seal was easy using a flat blade screw driver to push it in. Also it is a touch wide once it is started I pulled it, stretching it a bit and making it thinner. It went right in.

View attachment 604937

Final shot if what it looks like at the end of the channel. I then cut it to just the right length.

View attachment 604938

It works perfectly.
A little snug when pushing the cowl back onto the windshield but that's what I want.
And, I'm sure the seal is not one time use if you have to remove the cowl again. This rubber is way more resilient than the open cell oem foam rod.
Hope you all find this helpful. We won't have to worry if the car is left out int he pouring rain now.

Jenny Loves her Car since it's really like driving her 370z in suv format.....
View attachment 604940

DJ, thank you so much for this write up. It’s been driving me crazy the last few months trying to figure out all the issues I’ve had with water in the floorboards and electrical issues and I’m pretty sure it’s all related to this cowl issue. I’ll be going to Lowes tomorrow to try this out. Also in Nashville…. We get so much rain that if this works, will be a game changer for me. Thanks again bud.
 
So I did this, this afternoon and also replaced the two upper fender caps for the ends of the cowl overlay. Going to dry everything out tomorrow with the nice weather and then have the true test later this week with rain.
 
Super helpful post. This same issue just recently became a thing for me. I look forward to knocking it out over the weekend. Thank you!
 
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