Water leaking under dash when raining

[jklonowski]

I have a pretty good water drip under the dash on the driver's side by the fuse box. Trying to see if anyone has had the same problem before I tare apart the dash. Thanks guys for the help.
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[Altec]

Look inside the cowl. This is a common issue when trash collects in the cowl, and holds moisture. Mine rusted like this, but luck for me it rusted toward the engine bay.

[Hiluxxulih]

Ditto my 86 has rust holes big enough to pour golf balls into the cab .

[dmartin1]

check the windshield seal too,and for rust holes around the area....

note- mine actually had a small crack i the window from a pebble in the corner,and the water seeped through the glass,down behind the dash and to the floor by the fuse box.it had also ran in the crack of the glass to the metal of the cab where the glass sits and started to rust it.good thing i caught it.

[justpball]

windshield seal on mine leaked too

[blackbeaSSt]

im still chasing mine. although i think mine is the heater core on the passenger side

http://67-72chevytrucks.com/vboard/s...d.php?t=423766

[RandyP]

If it's rainwater/normal water, you have a leak from the outside. If it is sweet smelling like antifreeze, it's your heater core. Pretty darn easy to tell the difference there.

I've been lucky so far and had no leaks on a square, but had one in a early 80's El Camino once that drove me batty. I finally ended up gutting the interior, removing the front sheet metal and going crazy with seam sealer on the firewall after getting a new windshield urethaned in place (vs the butyl tape install).

[blackbeaSSt]

Originally Posted by RandyP

If it's rainwater/normal water, you have a leak from the outside. If it is sweet smelling like antifreeze, it's your heater core. Pretty darn easy to tell the difference there.

I've been lucky so far and had no leaks on a square, but had one in a early 80's El Camino once that drove me batty. I finally ended up gutting the interior, removing the front sheet metal and going crazy with seam sealer on the firewall after getting a new windshield urethaned in place (vs the butyl tape install).

but would the heater core leak with no outside water coming in like rain?

[RandyP]

If your heater core is bad and leaking, yes. Are you saying the housing is not sealed up correctly on the firewall and causing a leak, or your heater core is leaking? A leak on the passenger side in the floorboard is generally a good sign your heater core is doing something bad. But you should be able to smell the antifreeze pretty easy, assuming you actually have antifreeze in your cooling system and not just running straight water for some odd reason. You would also notice a drop in your coolant level, depending on the size of the leak.

[blackbeaSSt]

Originally Posted by RandyP

If your heater core is bad and leaking, yes. Are you saying the housing is not sealed up correctly on the firewall and causing a leak, or your heater core is leaking? A leak on the passenger side in the floorboard is generally a good sign your heater core is doing something bad. But you should be able to smell the antifreeze pretty easy, assuming you actually have antifreeze in your cooling system and not just running straight water for some odd reason. You would also notice a drop in your coolant level, depending on the size of the leak.

yeah i got a leak on the passenger side but only when it heavily rains or i am washing it. i haven't noticed the smell of antifreeze and in no way running straight water

[TDS-MN]

Windshield seal leaks on mine, bottom driver's side. Runs down to the same area as the Original Poster. Leak is much worse if I leave the kick-panel vent open accidentally. So far I have not bothered to try and solve this, though.

[tucsonjwt]

Of the three squares I have owned, all 3 leaked. One, rust around windshield seal, one due to bad crimp from factory on upper right corner sheet metal (raised up metal caused seal not to seal correctly), one just a bad windshield seal. If your vehicle is in a rust prone part of the country, then I would look for a rusty cowl or rust around the windshield first.

[RandyP]

Originally Posted by blackbeaSSt

yeah i got a leak on the passenger side but only when it heavily rains or i am washing it. i haven't noticed the smell of antifreeze and in no way running straight water

I'd get the carpet peeled back and get in there (upside down works, so your head is under the dash) with the doors shut while someone starts running water over the firewall. Start at the bottom and work your way up with the water until you see the leak start. At least that would tell you the general area it is coming from. Could be a leak at the top of the glass and it is traveling all the way down. Water leaks are a &%*#$* to track down sometimes.

[blackbeaSSt]

Originally Posted by RandyP

I'd get the carpet peeled back and get in there (upside down works, so your head is under the dash) with the doors shut while someone starts running water over the firewall. Start at the bottom and work your way up with the water until you see the leak start. At least that would tell you the general area it is coming from. Could be a leak at the top of the glass and it is traveling all the way down. Water leaks are a &%*#$* to track down sometimes.

fortunately i don't have any carpet so that isn't a problem! crazy thing is unless its POURING down, it doesn't leak. if its just a steady rain, no leaks