Another driver's side water intrusion question.

[4th4]

First time I noticed water pooling on the driver's floor mat was after I washed the car.
Second time I noticed was the morning after a heavy rain earlier this week.

Tore the kick panels out last night trying to find the leak and noticed the flimsy insulated-plastic tray that slides in under the dash was completely saturated.
I've ringed it out and its currently inside drying but I'm still no closer to finding the source of the leak.

I checked the sunroof drains. The PO has already cut the nubbin's off the drain grommets below the A-pillar, and can both run a weedwacker line through it as well.

I've checked the gutter below the windshield for debris and it appears very clear (I think this car was garaged in it's life before me).
I have a wiper blade puller arriving in the mail today and I intend to examine that area a little closer, but from below the dash I can't see where water would be coming through.

Any advice as to where else I should be looking?

 

[oilhammer]

The pass-through for all the electrical bits in the plenum chamber maybe. If the chamber drains get clogged, the water builds up and will find its way through there.

 

[4th4]

The pass-through for all the electrical bits in the plenum chamber maybe. If the chamber drains get clogged, the water builds up and will find its way through there.

Thanks for the reply.
What/where exactly is the plenum chamber? Is this part of the gutter below the windshield and wipers or under the hood?

 

[oilhammer]

The space where the wiper motor, engine controller, glow plug controller, and if so cursed, the transmission controller live.

 

[4th4]

The space where the wiper motor, engine controller, glow plug controller, and if so cursed, the transmission controller live.

Copy that. Thank you.
I’ll check that area once I can remove my seized-on wiper blade arms.

 

[4th4]

I was able to gain access to the plenum chamber (thank god for the $10 wiper arm puller!).
There was a bit of debris built up. I cleaned it out the best I could but should I be worried about a deteriorated gasket underneath the electrical passthrough cover?

Some before and after:

 

[DivineChaos]

I was able to gain access to the plenum chamber (thank god for the $10 wiper arm puller!).
There was a bit of debris built up. I cleaned it out the best I could but should I be worried about a deteriorated gasket underneath the electrical passthrough cover?

Some before and after:

Snake the drain and make sure it's clear.

 

[tgray]

I have found it best to just pull this unit up and reseal the gasket. Sealing with it bolted down will only stop the leak for a while and then it will return. I have had to do quite a few of these. It is not that hard of a job compared to the frustration of smelling molding carpet and trying to dry everything out.. Even if that is not all your problem it is a job that doesn't hurt to do on an older car. Clearing the drains can and may work in some areas but where I live the rain can fall so hard it will flood the area and water will leak in the car.

 

[ToxicDoc]

Can the drain be seen in these photos?

 

[dhangejr]

My car had a bunch of crud in there causing problems. Clean it out and flush it with water and air if you can

do the same to the sunroof no matter what you think. Mk4 is notorious for leaking in the sunroof in multiple ways.

Different car but my brothers Nissan has to have the sun roof flushed 2x a year cuz of where he parks. That’s extream but even The seemingly invisible pollen can get in those drains and cause backups under heavy rain, so just cuz it’s been looked at once donot mean to overlook It.

 

[oilhammer]

The big hole in your pic off to the side, right past where the hood cable passes through, is where the water drains. You had a nice big debris dam before (beavers would be proud), and it was clearly letting water pool up right at that pass through cover.

Take the two nuts off, lift the cover up, clean and reseal or whatever you need to do under there. I am pretty confident that was your problem.

The opposite side of that chamber, but potentially having the same problem, is the lower housing that the cabin filter tray snaps into. Once the cabin filter is out, it too can easily be removed/cleaned/resealed.

Once you get everything squeaky clean in there (use some elbow grease and some spray cleaner and a rag...get it down to the paint, and don't forget around and behind the ECU in the middle), then some good spray wax in a squirt bottle will put a nice slick coating on the metal in there making it less prone for things to stick. And it will make cleaning it the next time much easier.

 

[turbocharged798]

Those covers warp and start letting water in over time. The early cars that use the 2 piece cover don't seem to have that problem as the cover is much stronger.

 

[oilhammer]

And just remember, it could be worse:

 

[csstevej]

Ive had the hood release cable grommet there in your photo bet deteriorated and cause a leak for me too.