Cab Water leak - what I found - 2006 Silverado ext

[indyjps]

Lot of threads on this wanted to share what I found if it helps anyone out.

2006 silverado ext cab, 4wd, 5.3 flex fuel.  73K miles.  I had other daily drivers in past and rarely dove this truck in winters unless needed - so its low mileage. 

 

Started getting wet carpet in drivers foot well after rains when parked outside,  water was collecting in wiring trough under the sill plate, and soaking across the drivers carpet pad.  I assumed a firewall or cowl leak,  IT WAS NOT.

 

Stripped the interior out of the truck, while im there im laying kilmat. Alternate dynamat brand, ive used it on other project with success.  

[diyer2]

Did I miss something?

Wheres the leak?

 

[indyjps]

Third brake light.  Flooded the area with hose no leak.  I ordered a new gasket anyway.  

Door seals - flooded a section at a time,   no leak.  I did pull the door seals, cleaned underneath and straightened the clamping channel for a tight fit

Door to door frame - i saw videos of water getting into area between door frame and firewall, theres a recess behind the kick plate that can leak.  Usually gets into the door wirng grommet.  No leak,  i did add black rtv to the wiring door seal seal, it was a loose fit. 

Cowl,  i pulled the cowl vent and wipers,  not clogged,  I did clean it well, wax what I could reach to prevent corrosion.  I flooded this heavily, 10 min of garden hose, trying to fill it up and mimick a heavy rain.  No leak here.  I exected this to be the source. 

A/C LINE ran a/c and watched the rain the find it,  no blockage. 

Rear window.  This is the source of my leak, kind of.  

As i flooded each area of rear window,  top edge, side edge i saw leakage into the bare cab.  

The water is sheeting down the back of the cab,  running around and thru the rear cab fresh air flapper vent.  The seal is not tight,  the vent rattles around when you grab it, the rubber is pulled away. 

[indyjps]

Water gets in around this vent.   Drains down the inside back cab wall,  the gooey factory seam sealer actually directs it to the right in this photo and theres a seam seal ridge that directs it into the channel under the sill plate where the seat wiring runs. 

Since the truck has a little rake to the body,  the front of the sill plate area sits lower than the rear and the water collects near drivers foot, in the channel and soaks across the jute padding into driver floorboard. 

[indyjps]

Heres the damage.   Ground down with wire wheel,  etched with phosphoric acid,  neutralized with baking soda multiple times, brushed on PPG epoxy primer, brushed on some random red emanel from a past project. 

The wiring brackets hold the sill plate, theyre pretty wasted.   Need to figure that out.   

[indyjps]

I plan to remove the cab vents completely, block them off with a plate.  The hole for the cab vent has an inward facing flange,  not sure if ill grind that off or leave it.   Seal it all up with seam sealer.  

 

I would prefer to weld the plate on from the outside,  but I dont want to pull the bed at this time.   Need the truck running soon and already have the interior destroyed. 

[indyjps]

Kilmat Install.  I ordered 80mil 36 sq ft.  36sq ft is not enough.  Ordered more.  Pic shows how far 36 sq ft got me. 

 

Theres a black plastic cover behind the pedals that runs across the firewall on both sides.  It has yellow open cell foam behind it.  Im removing that foam, zip tying the plastic cover up, and putting kilmat as far up the firewall as I can reach.   I will also use klimat on the back of the cab wall, with the jute.   Ill probably use some jutte on high areas of the cab. Trans tunnel, seat risers for additional sound insulation,  but there will be no jutte padding on low areas of the floor that could hold any water in the future. 

 

I did not order a roller,  I'm using rubber mallets to pound it down and set it along the ribs as I lay it.  Works great. 

[NARDA1]

I had the same issue with an 06 crew cab I had. My issue was caused by the floor liner mats I installed and the area where the door perimeter weather strip ends are butted together at the bottom rear of the drivers door. Melted snow and ice would pool in the mat and flow to the groove in the door weatherstrip and back to the butted ends, and then flow threw the butted ends of the weatherstrip into the channel under the sill plate, then when the brakes were applied the water was forced to the front and overflowed into the foot well.  The bad part of this was the water contained salt. I removed the door weatherstrip and replaced it so the butted ends were in the area between the fuse panel access and the floor. I also replaced the floor mats with ones that had a lip on them to stop the water from draining to the door area.

[indyjps]

Heres the cab vent removed,  inward facing flange ground down,  sharpie shows 10x4" cover plate.  11x5 would have been better if youre replicating this. Cover plate made from old school heavy duty filing cabinet.  

Take time to clean the edges well,  I hand filed to ensure they were smooth,  consider reaching up from the backside to smooth the seam sealer.

Dipped a gloved finger into epoxy primer and smeared the backside and brushed it on the front side. 

[NARDA1]

You might consider this or something similar to adhere that panel.   https://www.oreillyauto.com/detail/b/3m-4307/paint---body-repair-16614/sealers---adhesives-25204/panel-bonding-adhesive-25320/3e6756f6e8a0/3m-200ml-adhesive/08116/4462061/2011/chevrolet/silverado-1500?q=panel+bonding+adhesive&pos=0

[indyjps]

Ive used panel bond before, it is very permanant.   I want the option to remove this and weld a permanamet plate on from the backside / outside when I pull the bed.   The fuel pump will eventually go bad - ill pull the bed then.  Weld a plate fully on the backside of the cab.  

Panel Bond would be ideal if this was never to be removed. 

[indyjps]

Heres the plate installed.  Seam sealer i found locally after 3 stops, was pretty old / stiff once I popped it open.  Decided to forge ahead, look pretty shitty though.    Smoothed out the backside well.  I used self tappers to draw down the plate and compress the seam sealer, once it sets ill replace the screws with rivets to avoid screws hanging out the back end. 

 

 

[indyjps]

Kilmat installed

Reflectix bubble foil installed.   i have used this style of insulation in the past from specialty auto suppliers lobucrod.com but the website was dead 

First time using home improvement store version.  Reflectix sounds very crinkly, we'll se how it acts under the carpet.  I like the lobucrod version better.  I will glue the heel pads from the jute to this before putting carpet back in.  50 sq ft roll just did it.