Passenger floorpan leak

[GNICETRY]

Had some water leaking onto passenger floor. Found 1 leak which was coming from wire loom/grommet. Sealed up the A/C box pretty good everywhere we could reach. Windshield is not leaking. It only leaks when base of cowl is hit with water. The leak is coming from side of passenger footwell area. Can not see where. Doing some research and it seems that possibly where the floorpan and firewall meet is a source of leaks. A/C box trap was cleared out from debris- it was clogged. What next? Take off inner fender or the whole fender? We have to see in. Neighbor is helping me, he's pretty resourceful with cars.

 

[Buick Mark]

Pretty common for leaks in that area.
Start at the seams down low with a water hose and work your way up

 

[GNICETRY]

Thanks but I went as far as we could go with the fender/inner fender on. No way to 'see' the bottom or side of HVAC seal or body seems. Just wondering what next, fender removal or can you see/access it with just inner fender removed?

 

[GNICETRY]

Anyone???

Should I remove the inner fender? Or the whole fender? What would be the best way to access those seems and the A/C box?

 

[Blacky]

My leak in that area came from the roof rail

 

[John Larkin]

I would pull the fender. You will have to remove the header panel and the bumper filler also. Take your time. Might be a good time to service the power antenna if you have not already.

 

[GNICETRY]

Remove the header panel or just loosen it up?
How long would this take a person who knows what they are doing?

 

[Buick Mark]

Remove the header panel or just loosen it up?

Just remove the nuts where the fender attaches