Got a leak i cant find - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HvyChevy454 · 08-06-2002, 11:12 AM

got a leak somewhere from under the dash on the passenger side.i originally thought it was the antenna but i fixed that and her is still a leak it looks like it might be from the rubber around the windsheild b/c the dash will be wet and sometimes around a hard right turn my feet will get wet. it also appears that where the metal in the front of the cab it pressed together then spot welded it lloks liek there is an epxpandable foam sealer and that will have water on it. i know ther is no rust anywhere in that area b/c i had it apart. has anybody else had a problem like this?

**1970 CST Short Wide** · 08-06-2002, 12:45 PM

I had the same deal. Had a new windshield installed. Problem solved. Good luck

da-burb · 08-06-2002, 01:07 PM

It is probably the upper corners of your windshield. The factory manual shows 12" of sealant running both directions. I had a windshield and gasket replaced and it still leaked. I asked the shop what they put in and they said nothing should go in there, so I think it is a case of the truck being 10 years older than the technician.

If this is a driver kind of truck I would go to the loacal auto parts store and check the sealants isle. I used a product called flowable silicone. It is made for this type problem. You squeeze it in under the gasket and it will flow within the gasket and seal it up. I have used it and it was easy to do. Sealed it up perfect.

Southpa · 08-06-2002, 01:19 PM

We had a hard rain last night, I guess. Your post prompted me to go check out that very same corner and sure enough the new carpet is damp. Before I installed the carpet I can remember water collecting there after a rain. I guess I will take the glovebox out and see what there is to see. I suspect the drip rails on either end of the cowl (waaayyy inside) are not doing their thing. Water is supposed to flow to the back and drop down the rear part of the fender, I think.

jku72 · 08-06-2002, 02:39 PM

I bet more trucks do leak here than dont. All three of my trucks leak a little, some worse than others. Common problem.

Woody · 08-06-2002, 03:57 PM

There are 4 seams that the seam sealer dries up and cracks allowing this to happen. The 4 seams are 2 on top about 2-3" in from the sides and across the bottom in the same area. The rain gutter will cause problems also. Silicone sealer may help, but to do it right ......you need to reseal the rain gutter, remove windshield and repair the seams , then new gasket (with sealer) and reinstall the windshield. A lot more work than you probably were expecting, but worth it in the long run. Keeps the floors from rusting as bad.

If you want a quick/cheap/low labor fix, get a chalking tube of silicone and seal the gasket (glass to rubber and rubber to metal) and check along the top of the gasket for the seams be sure to seal them well. Remove the cowl and seal the lower seams, might also seal around the wiper motor.

HvyChevy454 · 08-06-2002, 11:19 PM

the thing is though i just put new rubber in and followed the directions to the t. i put 12'' of silicone sealant on the top corners. so i guess its the deal under the cowl. i guess ill pull the ac vent hoses and the cowl off and see what i can find. what really bothers me i think it leaked into the cab ran behind the dash and shorted out my instrument panel lights

08-06-2002, 11:12 AM	#1
HvyChevy454 Slowly getting CRSS... Join Date: Jul 2001 Location: Lutz, Florida Posts: 656	Got a leak i cant find got a leak somewhere from under the dash on the passenger side.i originally thought it was the antenna but i fixed that and her is still a leak it looks like it might be from the rubber around the windsheild b/c the dash will be wet and sometimes around a hard right turn my feet will get wet. it also appears that where the metal in the front of the cab it pressed together then spot welded it lloks liek there is an epxpandable foam sealer and that will have water on it. i know ther is no rust anywhere in that area b/c i had it apart. has anybody else had a problem like this? __________________ -Nic Lutz, Fl My Team Website The Heavy Chevy Website ------------------ 72 Cheyenne 10 LWB GM 12-bolt 3.08 w/ Auburn Posi 91 454 Edel Performer RPM Intake 750 cfm carb Comp Cam 268/.495 Hedman Headers Dual 3'' Exhaust 71 Cheyenne 20 4x4 Fact. A/C PS PB Tilt Currently in the works... Speak Softly and Carry A Big Block... There is No replacement for Displacement... "If everything seems under control, you're just not going fast enough." - Mario Andretti

08-06-2002, 12:45 PM	#2
1970 CST Short Wide Senior Moment Join Date: Mar 2002 Location: Pittsburg Ca Posts: 4,185	I had the same deal. Had a new windshield installed. Problem solved. Good luck __________________ 1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565

08-06-2002, 01:07 PM	#3
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	It is probably the upper corners of your windshield. The factory manual shows 12" of sealant running both directions. I had a windshield and gasket replaced and it still leaked. I asked the shop what they put in and they said nothing should go in there, so I think it is a case of the truck being 10 years older than the technician. If this is a driver kind of truck I would go to the loacal auto parts store and check the sealants isle. I used a product called flowable silicone. It is made for this type problem. You squeeze it in under the gasket and it will flow within the gasket and seal it up. I have used it and it was easy to do. Sealed it up perfect. __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

08-06-2002, 01:19 PM	#4
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,409	We had a hard rain last night, I guess. Your post prompted me to go check out that very same corner and sure enough the new carpet is damp. Before I installed the carpet I can remember water collecting there after a rain. I guess I will take the glovebox out and see what there is to see. I suspect the drip rails on either end of the cowl (waaayyy inside) are not doing their thing. Water is supposed to flow to the back and drop down the rear part of the fender, I think. __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.

08-06-2002, 02:39 PM	#5
jku72 Registered User Join Date: Jan 2002 Location: cornville, maine Posts: 659	I bet more trucks do leak here than dont. All three of my trucks leak a little, some worse than others. Common problem. __________________ jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers

08-06-2002, 03:57 PM	#6
Woody Registered User Join Date: Feb 2000 Location: Georgetown, KY, USA Posts: 631	There are 4 seams that the seam sealer dries up and cracks allowing this to happen. The 4 seams are 2 on top about 2-3" in from the sides and across the bottom in the same area. The rain gutter will cause problems also. Silicone sealer may help, but to do it right ......you need to reseal the rain gutter, remove windshield and repair the seams , then new gasket (with sealer) and reinstall the windshield. A lot more work than you probably were expecting, but worth it in the long run. Keeps the floors from rusting as bad. If you want a quick/cheap/low labor fix, get a chalking tube of silicone and seal the gasket (glass to rubber and rubber to metal) and check along the top of the gasket for the seams be sure to seal them well. Remove the cowl and seal the lower seams, might also seal around the wiper motor.

08-06-2002, 11:19 PM	#7
HvyChevy454 Slowly getting CRSS... Join Date: Jul 2001 Location: Lutz, Florida Posts: 656	the thing is though i just put new rubber in and followed the directions to the t. i put 12'' of silicone sealant on the top corners. so i guess its the deal under the cowl. i guess ill pull the ac vent hoses and the cowl off and see what i can find. what really bothers me i think it leaked into the cab ran behind the dash and shorted out my instrument panel lights __________________ -Nic Lutz, Fl My Team Website The Heavy Chevy Website ------------------ 72 Cheyenne 10 LWB GM 12-bolt 3.08 w/ Auburn Posi 91 454 Edel Performer RPM Intake 750 cfm carb Comp Cam 268/.495 Hedman Headers Dual 3'' Exhaust 71 Cheyenne 20 4x4 Fact. A/C PS PB Tilt Currently in the works... Speak Softly and Carry A Big Block... There is No replacement for Displacement... "If everything seems under control, you're just not going fast enough." - Mario Andretti



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