Paddling in the footwells yet again.

[spannerrash]

Three years ago I spent a lot of time and effort drying out the interior of my car and fixing (or so I thought) all the possible causes of water ingress. I had the interior and carpet completely out to dry everything off and clean the seats. It took me ages (see photo). The car lives outside as I don't have a garage but she has been dry as a bone, up until now.

I check the drains regularly and in fact, just have again. They are not blocked. Yet water in the front footwells. The only thing I can think of, as I believe I have cured all the usual suspects, is that the plenum chamber drains are partially blocked and the amount of rain we have had lately has overwhelmed them.

So to my point.

1, Has anyone ever totally removed the plastic diverter thing from under the plenum chamber? In effect, just leaving one big hole.

2, Can anyone see any disadvantage to doing this?

3, If I can reach it, can it simply be pulled off from underneath?

Thanks all, Frank

[MikkiJayne]

Its been removed on a couple I've seen. If you have skinny arms it can just about be reached from the passenger side wheel arch with the headlight level arm disconnected and the inner CV heat shield removed, although its still quite a stretch. Easier with the driveshaft out. The disadvantage is that it may allow the AC to pull in fumes from the engine bay.

If the plenum drain is full though, it should run through the AC drains. If those are clear it shouldn't be getting in to the cabin. It should be fairly obvious if its getting in that way.

Have you done Botang's hole? That drips on to the relay panel and makes the passenger side front carpet wet.

A missing boot cable grommet can allow water in above the battery and if the car is parked nose-down it can run along the chassis legs, under the back seat and in to the rear passenger footwells.

[spannerrash]

Botang hole plugged and sealed (see pic). No water in rear footwells but I also replaced the boot gromet three years ago as the battery box was half full of water when I bought the car.

[MikkiJayne]

That does suggest the AC drains then. Any water in the centre console vent?

[spannerrash]

No water in the centre console I can see or hear gluging with the fan on high output.

I have just quickly removed the drivers side transmission tunnel cover, where the acc red connector is and it does feel wet behind the sound insulation. I have blown through the acc pipe though, upwards and downwards and it seems clear.

It looks like I'm gonna have to remove the insulation tomorrow and run a hose pipe over the wind screen. See if I can find anything. It's a real pain though as I'm trying to use this good weather to get the rear end Re-built.

It's a good job these cars are made of aluminium otherwise with all the water ingres issues there wouldn't be any left. They'd av all rusted away by now.

[HPsauce]

MJ is right in that an overflowing (maybe just partly-blocked) plenum drain will run into the condenser tray. But that won't cope for long.
The problem is that the condenser drains are much smaller as in theory the condenser tray only ever has completely clean water condensed from the air, no debris, and at a slow flow rate.

Of course, in reality, as the tray isn't sealed some dust etc. finds it's way in so occasionally unblocking of the infamous "orange drains" is recommended.
BUT the plenum is inevitably filthy so any overflow has a high chance of bringing bigger debris that will quickly block the aircon drains.

The end result in my case is that the plenum overflow is usually polluted with small seeds (birch for me) which apart from blocking the aircon drains also come blowing out of the air vents when they've had a chance to dry out!
Trimming the tips of the orange drains to improve flow is definitely beneficial.

[Audifan]

Originally Posted by spannerrash

plenum chamber drains

Where is this plenum chamber located?

Last year I had water leaking into the cabin that I eventually fixed. I checked my sunroof drains and they were draining but the rear ones were a bit slow to drain. I need to fix that. I had to clear out the two orange drains at the transmission tunnel. I also had to clear out the black rubber drains for the front wheel wells.

Since joining this forum I've learned a new area where water leak can happen called Botang's hole and air con drains. How many Botang's holes are there? And where are the air con drains located?

[MikkiJayne]

Plenum is the rain tray - from the base of the windscreen to the engine bay bulkhead. The main drain for this is almost inaccessible in an auto car, underneath the AC housing, but in a manual you should be able to reach it from underneath.

There's only one Botang's hole on the left side (same for both RHD and LHD). Aircon drains are the orange ones.

[Audifan]

Is the plenum/rain tray area where the windshield wiper linkage is installed?

I'll take a look at the Botang's hole when I get time to and inspect the condition of it. Good to know that I already took care of the air con drains.

Is there any other areas to inspect for possible water to leak inside these cars?

[HPsauce]

Originally Posted by Audifan

Is the plenum/rain tray area where the windshield wiper linkage is installed?

Yes, but the water runs to the centre underneath the cabin air intake unit and down through a container with two large drain holes, one each side of the transmission.
The lowest part is number 26 on the attached diagram, the rubber tips can get blocked, as can the two holes in the plate above it.