Water through firewall - I’ve got rainwater coming through the firewall of my 1973 Plymouth Scamp. For disclosure, am investigating tomorrow but wondering what might be the cause of it. When driving in heavy rain it’s actually dripping through the firewall under the steering column, behind the dash (no doubt past/over electrics) and into footwell near pedals. Any ideas on where it might be coming from and how to fix?
Water dripping through firewall behind the dash
- Thread starter Tuesday
- Start date
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It's very likely coming from the wiper post seals and gaskets.
Not terribly complicated with just heater, but if you have AC it's not going to be fun
Wiper Pivot R&R and Zerk Install
Wiper Pivot R&R and Zerk Install
Professor Fate
Push the button, Max...
1.) Failed wiper pivot seals
2.) Plugged cowl drains
3.) Rotted out lower (inner) cowl
4.) Windshield gasket/seal leaking or incorrectly installed
2.) Plugged cowl drains
3.) Rotted out lower (inner) cowl
4.) Windshield gasket/seal leaking or incorrectly installed
Thank you for the link. I’ve got AC !! Is the install problem just lack of space? Doesn’t look much fun either way, presuming there’s no ‘temporary’ fix from above if it’s the wipers?
That's a hellava nice how to!
In my dart with heat only, everything was easy to access
With AC the under dash space will be tighter.
REMOVE THE FRONT SEATS!
Big guys like me really benefit from the front seat removal and it only takes minutes, yet people will do everything in their power not to have to do it. lol
harrisonm
Well-Known Member
In a way, you covered it, but I was also thinking "rust holes under the Windshield gasket.
Hell and here I was trying to be optimistic. lol
Nailed it!
Would have to have been a pretty impressive heater core leak for the firewall on the passenger side under the heater core to be so rotted it’s sending water all the way to the opposite side at the steering column and pedal box.
I mean sure, a long standing heater core leak can rust out the firewall.
But given the OP’s description of where the water is and the fact that it’s a ‘73 Duster, well, I think @Professor Fate covered it.
On my ‘74 Duster I had 3 out of 4, the wiper pivots leaked, the cowl drains were plugged and there was a windshield seal leak too. All of which put water exactly where the OP described.
The cowl drains are big one, all the stuff on the floor in this picture came out of the cowl on my car…
Fortunately being a California car all that junk didn’t rust out the lower cowl.
My experience has been a bit different.
I zerked my pivots because my leak was worse if the wipers were on.
My leak was more or less directly over the fuse box.
The pivot is more over the steering column.
On mine I can see water wick around my windshield gasket and glass and build a small pool of water in the 2 lower corners.
My thinking was if it did not come from the pivots (I don't think it was in hind sight) at least after 56 years my pivots got lubed.
My next thought as to why worse with wipers on... Wiper drags water up to the left edge of the windshield, that water adds to the load on the leaking gasket.
After I discovered the leak (on my way to Bandamere speedway last year) I took all the exterior chrome off (convertible)from around the windshield and cleaned up the goop and old foam. No rust in sight but the gasket was not so playable any more.
I know the windshield was replaced once in the late 79s early 80s and the gasket MAY. have been reused.
I can see where sealer had been applied to various places but not on the outside along the sides or along the bottom to the body.
I have a new seal but put off having it installed (not sure why)
Not sure if this helps
Professor Fate
Push the button, Max...
Don't forget, Bewy's in Australia- his heater core IS on the left hand side! (RHD)
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Don't forget, Bewy's in Australia- his heater core IS on the left hand side! (RHD)
The thought definitely occurred to me but even if it is he should know that the vast majority of cars discussed on this forum are LHD and there are quite a few fairly significant differences
Professor Fate
Push the button, Max...
I'm sure... just trying to keep things on the lighter side!
Here is where they rust through the cowl. There is no paint under there. So spraying Cavity wax in the cowl on all Mopars is a good idea.
Great pictures, definitely shows the spot they rust out in the lower cowl.
Pretty sure on a '73 AC car though there isn't a cowl vent on the driver's side, it'll just be a flat section of sheet metal. The passenger side will be the same though.
el5dart
Well-Known Member
my leak turned out to be coming from a screw hole where a junction for the windshield washer hoses plug into right on top of the cowl under the back edge of the hood. it was leaking in to the drivers fresh air box from there and into the floorboard. so look to see if your missing that hose splitter and there is an exposed screw hole
Update: again thanks folks, your advice is ‘always’ golden. I managed to clean out the cowl drain holes with a flexible drain unblocking pipe. Miracle of miracles there is an odd cover for something on the cowl wall - seen picture here with arrow pointing at it - I was able to remove this and then get a decent blast of water down there to both sides. Loads of gunk came out - leaves, pine needles, even earth. Not sure how much is left but hopefully will make a difference. If it still leaks with the wipers on, will tackle the gaskets. Also found a couple of leaks along the join of the cowl cover to the firewall when flushing (not a problem a problem for dash, but looks like water is leaking into engine bay, so fixing that), have ordered some Butyl Rubber sealant tape to shape and press into those spots - hope that helps stop water getting into engine bay. Fingers crossed for a drier drive to work this week - being my daily driver and with storms forecast most of the week, expect she’ll get a decent road test!
JDMopar
Well-Known Member
A few more places to check if it still leaks. Make sure there is a foam seal between the hole in the firewall and the plate around the steering column, where the column goes thru the firewall. You should be able to see it best from the engine compartment side. Also, look in the door jambs, right above where the door hinges bolt to the jamb, you will see the seam where the upper and lower cowl joins. There should be drain holes in those seams, to allow water to run out of the cowl. If those holes are stopped up, it could cause the water to pond up and find a way out elsewhere. A coat hanger, shop vac and an air hose with a blow nozzle on it can get a lot of junk out of a cowl. Good luck to you. Cary traffic is bad enough without water drippin on your feet!
Thanks JD - I spotted that steering column hole the other day when I was trying to fix the bust link in my wiper transmission, a pivot bushing had broken - new problem!! Hopefully leak is sorted - but can’t tell until I’m stuck in the rain and now can’t even test that now without wipers !! Will foam steering column hole for sure!! Definitely in this for the love of cars and not practicality.
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