[Mk4 Golf] Nearside rear foot well leak - Interiors - uk-mkivs

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Nearside rear foot well leak



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#1 ttg4l

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Posted 08 December 2020 - 11:08 PM

Usually with a leak I'm pretty confident it'll be the door panel seal, but for this instance I've put a bead of silicone around the panel and around the speaker but there's still water ingress.

Intially it appeared to keep the carpet dry, but we had a heavy downpour last week and the carpet was wet again. Lifted the carpet and dried it out, and then we had some lighter rain the next day while the carpet was still up, and there was no additional water in the car.

My confusion is about a pollen filter leak, would a pollen filter housing leak cause the front nearside footwell to be wet as well (99% sure it's dry)? And am I right in saying that there could also be a leak from the tray that sits on top of the pollen filter when it's installed? And if so, would that make the front or rear wet? In my mind it'll overflow from that tray because of the angle of the car, then flow straight into the pollen filter and down to the rear footwell (rear offside is lowest corner of the car, so the tray above the pollen filter does collect water and not drain into the nearside scuttle drain hole until I move the car).

All 3 other footwells, boot and spare tyre well are dry. I've ruled out a rear light seal, bumper vent seal and boot seal because of this.

There is of course a chance my silicone sealant has failed/not set properly. Anyone got a good suggestion for a particular sealant to use if I were to re-do it? I used bathroom sealant for around the metal door panels around 2-3 years ago (worked great back then), and just all purpose clear silicone for the speaker.

If anyone could shed light onto where to go next with this, it would be much appreciated.


#2 mur3633

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Posted 09 December 2020 - 08:20 AM

Did you check rubber caps on floor?

#3 ttg4l

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Posted 09 December 2020 - 08:30 AM

You mean underneath? Not yet, but I didn't think to because the water comes in when the car is parked, not driving, unless that would make a difference?

#4 Blitzerman

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Posted 13 December 2020 - 11:27 PM

Its very unlikely to be coming from under the floor, ive never experienced any relatively modern car doing this.

 

Did you remove the bolts from the metal door panel and seal under it? or just around it without removing the bolts?

 

Did you pull the rubber under the door forward to see if it released water? theres also a few holes running under there to allow water to escape, may be blocked.

 

Rear lights could possibly leak and find its way forward if you park facing slightly downhill.

 

Even the air vents in behind the rear bumper could leak and also make water go forward if facing downhill. (if you want to see one, the drivers side (RHD) can be viewed easily, remove the little hatch thing in the RHS of the boot, and look down to your right there will be a plastic square with 3x rubber flaps in it)

 

Oh and for the pollen filter housing to leak, usually that little piece that has to be removed on top to replace the filter, has to be damaged meaning water drops directly onto the pollen filter itself.

 

Off the top of my head i cant remember if the lower housing is a sealed piece of plastic, or the metal work of the car moulded upwards to stop water entering :/



#5 ttg4l

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Posted 14 December 2020 - 12:37 PM

Its very unlikely to be coming from under the floor, ive never experienced any relatively modern car doing this.

Did you remove the bolts from the metal door panel and seal under it? or just around it without removing the bolts?

Did you pull the rubber under the door forward to see if it released water? theres also a few holes running under there to allow water to escape, may be blocked.

Rear lights could possibly leak and find its way forward if you park facing slightly downhill.

Even the air vents in behind the rear bumper could leak and also make water go forward if facing downhill. (if you want to see one, the drivers side (RHD) can be viewed easily, remove the little hatch thing in the RHS of the boot, and look down to your right there will be a plastic square with 3x rubber flaps in it)

Oh and for the pollen filter housing to leak, usually that little piece that has to be removed on top to replace the filter, has to be damaged meaning water drops directly onto the pollen filter itself.

Off the top of my head i cant remember if the lower housing is a sealed piece of plastic, or the metal work of the car moulded upwards to stop water entering :/


Thanks for the response.

I slackened the bolts and ran the bead underneath, but I'm pretty sure I didn't clean out all of the old membrane seal so that could have caused it to leak again (was at least a couple years ago so I can't say for sure). For the speaker it was just a bead round the bottom of it, didn't fancy drilling rivets out.

The drain holes on the door are clear, one was blocked but I pulled a chunk of mud out of it. The rubber does still catch water though, I was debating cutting away the last cm of it on the end of the door closest to the rear of the car to try and resolve that.

Rear lights and air vents can be ruled out for the moment, front of the car is higher than the rear.

The bottom housing on the pollen filter housing has a seal against the body, but I think that's fine because the front carpets are dry.

The plastic cover that is removable for the pollen filter is intact, I was just curious about the angle of the car allowing it to overflow into the filter instead of draining off to the passenger wing drain hole in the scuttle area.

#6 ttg4l

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Posted 22 December 2020 - 11:53 PM

Just to close up on this, it was the pollen filter tray overflowing into the car through the nearside rear floor vent.

Went to take off the pollen filter cover and noticed the tray full of water. Jacked up the driver's side and watched all the built up water pour out the passenger wing drain and left it in the rain. No water into the car, which explains why it was only when the car had stood in rain for a couple of days (allowing the tray to get full of water), or when it was very heavy rainfall (tray gets full quickly) that the car leaked. I've since reduced the angle that the car is parked at and left it in heavy rain and constant rainfall for a couple days, and no water in the car. Everything else is the same, same direction and offside rear is still the lowest point, just the angle of the slope the car is on is smaller.

I'm going to re-do the silicone on the doors anyway, just to be on the safe side.

Not sure what else to do about the flawed pollen filter design, other than just being wary of the angle that the car is parked at.

#7 ttg4l

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Posted 11 January 2021 - 02:48 PM

Turns out it's not all sorted.

 

After leaving the car for a week, with 2 or 3 rain spells in that week, there was very small amount of water in the foot well. Less than 100ml I'd say, compared to 500ml+ before. Also, I wouldn't have seen it had the carpet not been up, it would've soaked into the underlay. 

 

It's definitely less, but it's more than there should be.

 

As before, front foot well completely dry, and the water is nearer the central tunnel than the door, so I'm confident it's not the door (the water would need to cross a dipped channel in the metal floor before getting to where it is if it were the door).

 

So the current points are as below:

  • Reducing the angle the car is parked at has helped, but not completely resolved. O/S rear is still lowest point of the car, and the water does appear to be coming from the floor vent still.
  • The pollen filter tray does still hold water in this angle. Jacked up O/S and water poured off the housing and out the N/S scuttle drain.
  • It only happens if either there's been one heavy rainfall, or a multiple days of normal rainfall - implies to me that the water is sitting somewhere then overflowing, as oppose to a continuous leak.

 

I've now reversed how the car was parked so N/S front is the lowest point of the car, and the pollen filter tray is tilted down to prevent it holding water. Here's to hoping it doesn't start soaking a different foot well in the car.



#8 adam-

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Posted 11 January 2021 - 09:03 PM

Just to close up on this, it was the pollen filter tray overflowing into the car through the nearside rear floor vent.

 

 What a follow up.  My mind is blown.  Thanks for this! 


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#9 ttg4l

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Posted 11 January 2021 - 09:21 PM

 What a follow up.  My mind is blown.  Thanks for this! 

:(







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