rare70cat

iTrader: (2)

Hey guys, Today while running a new wire for the new fuel pump,I discovered my drivers side carpet was WET! 81 GSL. I have a rubber floor mat so I didn't notice. Any ideas? Previous owner said he cleared the sunroof drains. I took my cowl off and pressure washed all that mess out.

Davin

iTrader: (14)

you said 'wet carpet'!

Aerodynamic Pants

I haven't had my FB long so I'm not exactly sure where the heater core is,but that might be a possibility. Or perhaps the door weatherstrip?
Maybe a grommet rotted in the firewall and is letting in water?
What about the cowl vents between the glass and hood, is the metal in there solid?

cawcawcacaw

i have the same problem, haven't found out where the water is coming from yet in my 83 gs driver side floorboard.

farberio

iTrader: (7)

Also check your clutch master cylinder.

Crit

iTrader: (6)

'If the rear seal on your brake master cylinder fails, the fluid will get through the booster and run down the firewall, right in the footwell. If it's closer to the tranny, then it's likely a failure of the heater core or the coolant hoses that feed it.

Is your brake fluid low?

rxtasy3

iTrader: (2)

what's it smell like? then and only then will u know where to start looking.

10yearrx7

iTrader: (2)

I had this same problem in my fc. it was raining and after I drove only the driver side carpet was wet(and it was soaked). I looked under the car and discovered there was a plug missing. I dont know if 1st gens are the same but it's something I would check out.

ZoominFD

Smell? Could be a leaky heater core, or water is getting in there. Are there any holes in the firewall where the water could be getting in from?

rxtasy3

iTrader: (2)

not that i know of unless rain water that gets into the cowl doesn't drain out and has rusted out the firewall. or it leaks in around the vent that passes thru the firewall into the cowl area.

djs2571

The metal a-pillar cover can channel water to the front part of the door seal. The cover has a little plastic edging around it that can keep the door seal from sealing, which can track water to the interior.
Look carefully when driving in the rain, I had water drops forming on the inside edge of the window frame due to water blowing in - and yes, finding the floorboards wet as well.
One fix is to silicone the front side of that a-pillar cover to the windshield. This cuts down on wind noise as well as the path for water ingress.