I seem to be having bad cab rust even thou im in the northern states. I am trying to protect my truck but it seems like the most of it is in the front and rear corners of the cab. Could it be caused by water running down the windshield down into the bottom of the cab likewise with the rear window.

 

hhmm, i dont see how water just running by could cause rust unless it is sitting water. most of the time rust in northern vehicles is from salt they use on the roads during the winter..i know its not winter but rust does take time to form

 

My rear window had a leak, rusted out the corners of the cab in the rear. Took the headliner out, pumped silicone sealer around the top of the window where the gasket is, problem solved.

 

Seems right cuz middle of the bottom of the cab is fairly in good shape. But rust seems to be working up the rear of the cab behind the plastic trim behind the rear door didn't seem like my rear window leaks but how exactly did you notice the leak.

 

During a bad rain storm, my headliner was wet in the rear. But thats not to say it cant leak from the bottom of window.

 

Mine doesn't leak from the top except from the front windshield