Rain leaking into cab

[CarbonBowtie]

I have the same leak 1999 NBS Ext Cab.

It leaks on the floor in the Passenger side front and travels down the
sill to the back floor and soaks that too. Not Antifreeze it is just plain water.



I do not know what to do about it either. It just started doing it one day when it rained real heavy for hours.

It screwed up my amp rack (blew all the fuses and destroyed one of my Signal cables) got lucky as my rack is raised and the amps were saved by 1"

PLEASE SOMEONE HELP US!

[speedjunkie]

Add me to the list on my 98. Had the water in the header motor and I thought that it ruined it but when it dried its ok. So is there a fix to this yet?

[rmckee1]

Success!!! I have been chasing the same leak on the passenger's side floor. It happens worse after just sitting in the rain for a few hours. Just had the windshield replaced but it had leaked before for two years. This is a '94 1500 Ext Cab. I removed the two small cowl grates and the center grate that goes all the way across and siliconed all the screw holes and replaced all before it set up. Then siliconed the top of the screws on the side grates after being screwed down. Then for good measure I siliconed all the way across the top of the windshield. This works best if two strips of masking tape are used at the top of the windshield with just a small slit so that the silicone doesn't get everywhere. I did this twice with a couple of days in between to set up. No more leaks and I have had two rains! Don't know which did the trick but one way to tell would be to run some tape across the windshield top seal and see if it leaks. If so, then just do the cowl grates. I got impatient and did both.

[Tasty]

Hmmm, I can't see how that would fix it as those screws just go into the superficial upper part of the metal there near the bottom of the windshield. None of those holes penetrate through to the cab. Weird fix, but glad it worked for you. I think mine is coming in somewhere else though. It seems to drip right from the bottom of the blower motor onto the floor mats.

[rmckee1]

Tasty, mine was leaking exactly as you describe. It seemed to drip from the bottom of the blower motor. You could tape up the top of the windshield and see if that stops the leak. If so, then seal it. If not, then you could try the cowl grate screws. Not much trouble and only a few bucks for the silicone.

rmckee1

[RJMech]

My 98 ext cab has the passenger floor leak as well. Ill try the silicone trick. thanx

[blazenlo95]

Add me to the list! Mine don't leak on the floor mat though. Mines wet under the mat. Running down the firewall or something. I'll work on it after winter.

[Tasty]

Yeah, the ONLY thing I am grateful about in my leak situation is that it is on TOP of the mat so I don't have a stinky interior. I hate mildew.

[kawamatt2]

I have a very slight leak in a hard rain, but it gets like ten times worse when i turn on the defroster. Could this mean that the condenser drain hose is clogged?

[Tasty]

Well, check it and see. It is on your fire wall in the engine bay and looks like a little black down spout. Examine it and see if it is fouled.

[speedjunkie]

No the water is leaking into the blower motor and when you turn it on it spills out on to the floor.

[Whifflebat]

I had a leak there on mine when I got it, I sealed up those screws and no problem since.

[RJMech]

I RTVed those screw holes and waited for the rains to come--success. Thanx for the help everyone. Nothing chaffes me more than interior water leaks, especially because I traded my monte ss for this truck because I was sick of the t-top leaks it had.

[Z71Nutty]

Anyone have pics of these screws to RTV them? Got a 97 it rains hard all day get in truck to drive home then it leaks out some on the pass. side and stops.

[CKTA]

Read the whole thread There are pics in it.

[BLACKJACK5810]

yea my 1999 tahoe does the same thing. since i already had half the interior pulled i took up the carpet and the kick panels and all the stuff on the passenger side near the floor. there is a slow leak down the seam wear the kick panel and floorboard meet. i've looked and looked with a hose squirting and still can't find the source.

[buckslayer]

I did this fix and it worked. All but one of the screws - either far left (passenger side) or sencond from left DOES go into the blower motor area. The rest, as stated somewhere, just go through the sheet metal. It takes about 5 minutes to do.

[kenman1717]

Originally Posted by blazenlo95

Add me to the list! Mine don't leak on the floor mat though. Mines wet under the mat. Running down the firewall or something. I'll work on it after winter.

funny you mention that, i didn't realize mine was leaking until you said yours is only wet under the floor mat, mine too, i just thought i spilt something, but everytime i take them out after it rains the floors always wet.

[CKTA]

OK guys.....by dumb luck I found out i have a leak too. On the drivers side tho. Checked the pass. side and it's fine. Here in Jersey we have gotten HUGE ammounts of rain and flooding in the last month. I origanlly thought my wet carpet was from boggin' through 2' of water, but after leaving towels on the floor I noticed they were still getting wet after yesterdays rain.

I really looked into this last night and have come up w/ a few things.....

1. Putting silicone on the cowl screws will do NOTHING. Those screws go into the cowl area which is a huge open area.

2. "Eric G" siliconed area makes sense and I looked into that, but mine appeared in very good shape.

So what i did was pull the truck back out side and let the hose run for a while as i was inside. Took a while, but I finially saw a small amount of water starting to run OUT of the seam sealer where the floor, firewall and kickpanel sheetmetal meet. I can only assume from this that it's leaking from the cowl area being I CAN NOT see water running into the cab only out of the seam sealer. Back to the cowl area I went. I cleaned the area (not that dirty) and found something that could be the problem....

When the cowl area fills w/ water it drains out of a "tube" on the drivers side. (pop the hood and look for a black plastic housing under and to the right of the cruise box and under the washer tube.) I took that off (the bottom screw is a PITA) hoping that was clogged. No dice, nice and clean. I cleaned out the cowl area going into that plastic peice and noticed that there was what looked to be a void in the seam sealer there. I cleaned that out siliconed it up and reinstalled everything.

As I made my way back into the cab to silicone up the area where the water was leaking out from I also noticed that there was a void in the seam sealer where the firewall, inner floor and outter floor come together.

Only time will tell, it's still raining and the silicone was still wet so i left the truck in the garage last night. I have the carpet spaced up so it will dry and so i can keep an eye on this. I'll keep you guys updated.

[matt trakker]

I had a leak in my 93, I found the top of my windshield was letting water in, and it was running across the top of the windshield frame, then down the a-pillar trim, to the floor. I had a chip in it so I got a new one put in because my insurance covered it.

When I went to the glass shop, I was told that on the 88-98 style trucks, there is a pinch weld under where the top of the windshield seals. This pinch weld gets surface rust on it, and as soon as it gets bad enough, it pops the adhesive away from the metal, I was told that next time I get a chip, to take my truck to a body shop, have them blast, then prime and paint the top of my windshield frame, then have the new glass put in.

In my experience I won't use silicone on my glass seals anymore, it just causes more problems, expecially when you try to fix it correctly...