Leak under dash

[clemsonteg]

I have noticed a few times in the rain that I appear to have a leak under the dash on the driver side. I believe it may be coming through the windshield gasket, but I'm not sure. I noticed a small weep hole in the dash and the water looks like it may be coming in through the seam to the left of it. I looked under the cowl and all over the gasket and couldn't find any obvious holes on the outside. My only though was that it is somehow getting behind the gasket and I am guessing that the windshield frame is welded together and the water is finding its way through a seam once it gets behind the gasket.

I will have to have the windshield replaced when I have the truck painted due to a crack.I am trying to find out where the leak is so that I make sure it is sealed before all that happens. Has anyone else experienced this before?

[firedemon]

ya mine leaks on the passenger side somewhere I didn't find out till I replaced my glovebox first rainstorm hit a corner a gallon of water comes out the seams of the door still don't see where its coming from exactly but my gasket is fairly dry rotted . need another glove box now

[9teen69]

Generally comes in top corners of window seal. I had a new Precision seal installed and still leaked when going down highway because the installer didn't use Butyl sealant.

Insist on them using Butyl sealant. NAPA sells it.

I tapped around my gasket, pulled it back and squeezed in the Butyl sealant with a popsicle stick...no more leaks

[firedemon]

Originally Posted by 9teen69

Generally comes in top corners of window seal. I had a new Precision seal installed and still leaked when going down highway because the installer didn't use Butyl sealant.

Insist on them using Butyl sealant. NAPA sells it.

I tapped around my gasket, pulled it back and squeezed in the Butyl sealant with a popsicle stick...no more leaks

outside , inside or both?

[swamp rat]

I'd suggest you pull the cowel and have a good look at the body seams underneith on each side of the windshield.

[9teen69]

I just did the outside

[LockDoc]

Originally Posted by clemsonteg

I have noticed a few times in the rain that I appear to have a leak under the dash on the driver side. I believe it may be coming through the windshield gasket, but I'm not sure. I noticed a small weep hole in the dash and the water looks like it may be coming in through the seam to the left of it. I looked under the cowl and all over the gasket and couldn't find any obvious holes on the outside. My only though was that it is somehow getting behind the gasket and I am guessing that the windshield frame is welded together and the water is finding its way through a seam once it gets behind the gasket.

I will have to have the windshield replaced when I have the truck painted due to a crack.I am trying to find out where the leak is so that I make sure it is sealed before all that happens. Has anyone else experienced this before?

Try running a bead of sealant from the top corners outside, 6" each direction, horizontal and vertical. Also check what swamp rat suggested.

Originally Posted by firedemon

ya mine leaks on the passenger side somewhere I didn't find out till I replaced my glovebox first rainstorm hit a corner a gallon of water comes out the seams of the door still don't see where its coming from exactly but my gasket is fairly dry rotted . need another glove box now

Before you put your new glove box liner in be sure and run a bead of sealer along the seam on the side of the liner. That way if you do have a leak the water will not run into the inside of the glove box....

Originally Posted by swamp rat

I'd suggest you pull the cowel and have a good look at the body seams underneith on each side of the windshield.

A good idea....

LockDoc

[Andy4639]

Hard rain with wind + gasket leak. Water gets behind gasket and seeps into the truck and down the hole to floor. A little clear sealer will fix it most of the time.

[firedemon]

ive had the cowl off it looks real good I do see water stains coming down from both upper corners of the windshield on the inside and I hope I'm not stealing your thread

[Jurassic-1]

How does the glass fit in the rubber seal. The newer glass is thinner than the factory glass I found my rubber seal is not very tight. When I wash the truck if I spray directly on the glass it will leak around the glass on to the dash. You could seal the lower portion and stop it but I keep mine inside and decided not to bother.

[71CHEVYSHORTBED402]

Originally Posted by 9teen69

Generally comes in top corners of window seal. I had a new Precision seal installed and still leaked when going down highway because the installer didn't use Butyl sealant.

Insist on them using Butyl sealant. NAPA sells it.

I tapped around my gasket, pulled it back and squeezed in the Butyl sealant with a popsicle stick...no more leaks

Know if this Butyl sealant is recommended for those with stainless steel frames?

[cdowns]

sometimes if the gutter sealant is shot will cause a leak coming down the winshield post corners

[dirtyjim]

the body seam is probably leaking to but it is covered by sheet metal so you really can't see how bad it is without cutting a window. pull your cowl and run a water hose any where it could leak. then check under the dash to see exactly where it's coming through. mine was leaking at the seam in your picture and to fix it I has to cut windows on each side to get to it.

[clemsonteg]

Originally Posted by cdowns

sometimes if the gutter sealant is shot will cause a leak coming down the winshield post corners

Like te drip rail? That's possible for me since I think mine is shot and cracked in a place or two.

[9teen69]

Originally Posted by 71CHEVYSHORTBED402

Know if this Butyl sealant is recommended for those with stainless steel frames?

Yes, I have SS trim. A quick mock up with tape shows how you would tape (but a lot neater) and work the butyl in between the gasket and frame across and down the sides.

Dirtyjim is referring to the body seal under cowl. Also see my photo with the grey body sealer. The black paint is POR15.
I didn't cut holes, just squeezed a bunch of sealant on disposable gloves and reached down and worked over the seams.

Definitely check the drip rails.

Take the cowl off and it will take a lot of guess work out. Besides if you don't get it back on right away you can still drive around without it

[71CHEVYSHORTBED402]

Originally Posted by 9teen69

Yes, I have SS trim. A quick mock up with tape shows how you would tape (but a lot neater) and work the butyl in between the gasket and frame across and down the sides.

Dirtyjim is referring to the body seal under cowl. Also see my photo with the grey body sealer. The black paint is POR15.
I didn't cut holes, just squeezed a bunch of sealant on disposable gloves and reached down and worked over the seams.

Definitely check the drip rails.

Take the cowl off and it will take a lot of guess work out. Besides if you don't get it back on right away you can still drive around without it

All good information, thank you. By chance can you provide a high level description for the steps involved for installing the window? I imagine it applies to both front & rear. I've seen the rope business. I believe the seal fits into the SS trim.

[jcis4me]

I had the same problem...
Did all the glass fixes replaced the windshield new gasket and all, still leaked. Took a look at the area between the drip rail on the top of the cab and where it meets, cracks and such, repaired the cracks in the sealer the factory put on it,viola no more leaks! Apparently water was coming in at the cracks and running down the posts and into the cab in the corner on the passenger side.
Hope this helps!
Marty

[clemsonteg]

And the winner is …

Drip rail. The sealant is dries and cracked along with the paint and it appears that water is dripping along the inside of the pillar and coming into the cab in the very corner of the dash. Next step is to clean out all the old sealer and figure out what to put in its place. Any suggestions?

[dirtyjim]

Originally Posted by 9teen69

I didn't cut holes, just squeezed a bunch of sealant on disposable gloves and reached down and worked over the seams.

I tried that first but I wasn't able to do a good job on it without cutting windows to get my big Viking hands in there and it really needed to be cleaned up and the rust removed from the seam. it was rusted through in several places and was just much easier to fix from above than below.

like most trucks it was run without a screen on the cowl and had years of debris that retained moisture. after cleaning 15 pounds of old leaves out it has a screen now

[dirtyjim]

Originally Posted by clemsonteg

And the winner is …

Drip rail. The sealant is dries and cracked along with the paint and it appears that water is dripping along the inside of the pillar and coming into the cab in the very corner of the dash. Next step is to clean out all the old sealer and figure out what to put in its place. Any suggestions?

most auto parts stores sell body seam sealer. autozone and oriely's local to me have it for around $15 a tube, i think the local napa carries it too