So im sure plenty of us bypass the heater core in our trucks when it leaks, or replace the weatherstripping on the doors when our floors get wet.... That's what i thought my leak was, although when i had an inch of water on my passenger floor(enough to make my weather tech mat float) i figured something was up, so i pulled the trim and carpet to find this little guy...





Yes that is the tread on my tire your seeing...

Wouldn't have though id have that there, considering my blazer has almost no rust otherwise, definelty worth checking this before bypassing a heater or changing seals.

 

Whoa!!!! Nasty. Seeing rust always makes me cry.

 

Where did your Blazer/Jimmy spend its formative years ?

 

As far as i know its been a florida truck its whole life( or at least a lot of it).

 

What year is that Blazer?

My 1994 has the exact same spot rusting. Amazing that it held 25 years in Switzerland with all the salt they throw on the roads during winter.

Seems that there is a weak point in the way it is assembled and once the sealant starts do dry it cracks and water can seep in.
I'll have to repair mine within the next two years or so. Probably once the engine is ready to be swapped.

Also have a closer look at the floor just ahead of the seat rails. This is where the cab supports tend to rust through the bottom from below.
Not much to see underneath but under the carpet the perimeter of the support is gone.

 

[QUOTE=error_401;713843]What year is that Blazer?

Its a 2001, honestly seemed like it shouldn't have been that bad yet, but i see what you mean by the caulk joint going bad being cause for this. Thankfully rust is minimal otherwise.