W205 drain pipes

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RadiumRob

New Member
Joined
Sep 11, 2021
Messages
11
Location
Dorset
Car
C250
Hi,

I have water in the driver’s footwell and completely saturated insulation material on the bulkhead above the pedals. This seems to indicate that the drains are blocked and water is overflowing into the cabin.

I have cleared leaves and debris from the areas around the battery and the ESP/fuse box but can’t find any pipes that should drain these voids onto the ground.

I’d be very grateful for any help in finding and clearing these.

Thanks
 
Check the drains near the wiper shafts....
Thanks. The holes in the plastic are clear. There are no tubes connected to the underside of that cowl(?) so the water runs into the bodywork around the battery LHS and ESP RHS. There are no drain holes in those areas as far as I can see.
 
Thanks. The holes in the plastic are clear. There are no tubes connected to the underside of that cowl(?) so the water runs into the bodywork around the battery LHS and ESP RHS. There are no drain holes in those areas as far as I can see.
I'd look at one of the parts diagrams on 7Zap Mercedes or other similar sites. You should be able to see where the drain pipes are located.
 
Not sure about your car but underneath my battery plate is a mess of wires that trap muck and in the second photo you can see a rubber (circled) drain which was blocked .


Battery plate.JPG Blocked.JPG
 
Thanks for your replies.

I removed the fuse box on the driver’s side of the engine compartment and looked around void beneath. There doesn’t seem to be a drain hole in that space so I don’t know what is supposed to happen to any water that gets in there by draining through the holes in the scuttle panel by the wiper arm. There is a solid grommet sealing a hole at the front of the void.

I removed more trim from behind the pedals. The cables that run through the fire wall are all dry even after last night’s heavy rain so I don’t think their grommets leak.

The sponge material behind and below the speaker (area marked by arrow) is soaking wet.

Is it possible that water gets in through the brake pedal actuator (top left of picture behind red by blob)? The pedal linkage (second photo) is bone dry.

I’ve ordered a replacement scuttle tray in the hope that this diverts water away from the firewall and brake servo. If that doesn’t help I’m right out of ideas.

Any suggestions?
 

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Hi,

I have water in the driver’s footwell and completely saturated insulation material on the bulkhead above the pedals. This seems to indicate that the drains are blocked and water is overflowing into the cabin.

I have cleared leaves and debris from the areas around the battery and the ESP/fuse box but can’t find any pipes that should drain these voids onto the ground.

I’d be very grateful for any help in finding and clearing these.

Thanks
Sorry I can’t help with your particular problem but as said by others I frequently check the drains around the wiper shafts which block easily. There was a thing on tv recently where they were using compressed air to blow through drains of that type.
As an aside we have a lot of wind noise from the front nearside and in investigating that we poured water into almost every roof and body panel aperature. We couldn’t find any conventional drain pipes and water seems to drip out behind the wheel arch liners. At the time it was disappointing.
 
Sorry I can’t help with your particular problem but as said by others I frequently check the drains around the wiper shafts which block easily. There was a thing on tv recently where they were using compressed air to blow through drains of that type.
As an aside we have a lot of wind noise from the front nearside and in investigating that we poured water into almost every roof and body panel aperature. We couldn’t find any conventional drain pipes and water seems to drip out behind the wheel arch liners. At the time it was disappointing.
Thanks.

Is yours a W205 too? It seems of that the scuttle pan drains don’t have pipes attached but just drain into a void that also doesn’t have drains.

Quite an oversight/cash cow finding on one’s perspective.
 
Thanks.

Is yours a W205 too? It seems of that the scuttle pan drains don’t have pipes attached but just drain into a void that also doesn’t have drains.

Quite an oversight/cash cow finding on one’s perspective.
Hi. Yes mines a 2016 W205 C250d which I’ve had from new and have been delighted with.
Two recent problems though.
Wind noise from the front nearside area which I and a local garage cannot get to the bottom of, and this year paint on the roof panel between pano roof and windscreen began to flake. It’s apparently a plastic panel and once the paint started to deteriorate it spread rapidly. Probably poor surface and sun damage. Just had it re sprayed (same garage as above) at a reasonable £146.
I haven’t had any water damage though, so fingers crossed.
 
Don't know if this is of any use but on a 2019 S205 i've noticed that behind the arch liner (back side of front wheels) there is a plastic drain pipe on both sides. It's fairly flat about 3 inches wide and about half inch deep. I've not paid attention to where it connects on the upper side however if you were to pour water down you windscreen, close to a wing, I'd expect you should be seeing it drain out mainly behind the front wheels behind the arch liner. If it doesn't then they're likely blocked, probably at the upper side where they're narrowest. One of the arch liner nuts also clamps these drain pipes and they feel quite loose once the liner is out. I'm not saying this is defo the cause of your issue but perhaps something worth ruling out?
 
Don't know if this is of any use but on a 2019 S205 i've noticed that behind the arch liner (back side of front wheels) there is a plastic drain pipe on both sides. It's fairly flat about 3 inches wide and about half inch deep. I've not paid attention to where it connects on the upper side however if you were to pour water down you windscreen, close to a wing, I'd expect you should be seeing it drain out mainly behind the front wheels behind the arch liner. If it doesn't then they're likely blocked, probably at the upper side where they're narrowest. One of the arch liner nuts also clamps these drain pipes and they feel quite loose once the liner is out. I'm not saying this is defo the cause of your issue but perhaps something worth ruling out?
That’s interesting, thank you. Presumably are the channels in the attached pics. The line drawing seems to suggest they connect to the plastic scuttle but there’s nothing for them to attach to and no sign of them. It makes sense that they might be buried in the wing I suppose but there’s only a very small drainage hole that I can see.

The foam that was previously fairly dry was saturated after last night’s heavy rain so I’m leaning towards the windscreen leaking but struggling to see how it can leak whilst remaining dry on the inside.
 

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That’s interesting, thank you. Presumably are the channels in the attached pics. The line drawing seems to suggest they connect to the plastic scuttle but there’s nothing for them to attach to and no sign of them. It makes sense that they might be buried in the wing I suppose but there’s only a very small drainage hole that I can see.

The foam that was previously fairly dry was saturated after last night’s heavy rain so I’m leaning towards the windscreen leaking but struggling to see how it can leak whilst remaining dry on the inside.
Yes this is the part i was referring to. When I'm back home Weds night I'll have a better look for you as I've got mine partly stripped back at the moment so perhaps can find a more positive location of where they attached at the top. They run down the back of the front wheel arches though, not inside the wing. The only other theory I've got is water being thrown up through the inside of the wing itself which could bypass the door rubber but you'd have to have a serious breach of the arch liner for this to be possible.
Also if you've a sunroof it might be worth checking around that in case water is getting in and running down inside of A pillar trim. I think A pillar trim is fairly easy to remove, just pop off the badge that says 'airbag', to find a screw. Pretty sure there's a youtube vid for this. It's certainly a mystery this one...
Hope you get it sorted soon
 
Yes this is the part i was referring to. When I'm back home Weds night I'll have a better look for you as I've got mine partly stripped back at the moment so perhaps can find a more positive location of where they attached at the top. They run down the back of the front wheel arches though, not inside the wing. The only other theory I've got is water being thrown up through the inside of the wing itself which could bypass the door rubber but you'd have to have a serious breach of the arch liner for this to be possible.
Also if you've a sunroof it might be worth checking around that in case water is getting in and running down inside of A pillar trim. I think A pillar trim is fairly easy to remove, just pop off the badge that says 'airbag', to find a screw. Pretty sure there's a youtube vid for this. It's certainly a mystery this one...
Hope you get it sorted soon
Thanks again, that would be helpful.

One thing I can be sure of is it’s not water spray - the car hasn’t moved for over a week!
 
Thanks again, that would be helpful.

One thing I can be sure of is it’s not water spray - the car hasn’t moved for over a week!
Not sure if this gives you much more than your diagram. This is the drain on passenger side. Looking from the top i couldn't see any opening into top of the drain but probably because battery tray in the way. If i get chance to remove this over the weekend i'l post an update
 

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Great photo, thank you.

I can’t see a drain in either of the voids but if I pour water in it results in a concentrated flow on both sides so I suspect the drains are connected and clear.

I’ve been running a heater and dehumidifier inside to dry the sponge out. In anticipation of the deluge I wrapped the windscreen and blocked the roof gutters as per pic. Hopefully it will be drier inside which should prove it’s the windscreen but I’m not holding my breath. IMG_5863.jpeg
 
Great photo, thank you.

I can’t see a drain in either of the voids but if I pour water in it results in a concentrated flow on both sides so I suspect the drains are connected and clear.

I’ve been running a heater and dehumidifier inside to dry the sponge out. In anticipation of the deluge I wrapped the windscreen and blocked the roof gutters as per pic. Hopefully it will be drier inside which should prove it’s the windscreen but I’m not holding my breath. View attachment 150295
Don't blame you. I was reading another thread regards a guy who's pano roof was leaking and he was talking about some kind of drain which runs down from the roof and possibly terminates into the top of the drain that i've been talking about. Seems crazy that a windscreen would leak since they're usually bedded on a continuous bead of silicon. At least if it stays dry while this cover is on you know it's getting in somewhere within that zone. If it still gets wet you can come up with some new theories.
 
Don't blame you. I was reading another thread regards a guy who's pano roof was leaking and he was talking about some kind of drain which runs down from the roof and possibly terminates into the top of the drain that i've been talking about. Seems crazy that a windscreen would leak since they're usually bedded on a continuous bead of silicon. At least if it stays dry while this cover is on you know it's getting in somewhere within that zone. If it still gets wet you can come up with some new theories.
So the poly sealing was moderately successful but there was water on the windscreen and in the engine bay adding the scuttle trays. And plenty in the foam too.

After it had dried I sealed around the windscreen using Permatex silicone sealant which was quite fluid and easy to apply. I’m fairly confident the windscreen can’t be letting water through now.

Also sealed around the grommets surrounding electrical cables and the bonnet release cable at the firewall. Another deluge last night and one area of foam is quite dry but another fairly wet - I’m not sure if that’s residual water from before.

Today I removed the wheel, arch trim, and the plastic drainage channel mentioned by DamoC43. It was bone dry inside and out despite the rain last night and today, so maybe water hasn’t been reaching it and backed up into the cabin instead? I cleared the void it was fitted to of leaves and debris that couldn’t be reached from the top and will refit it tomorrow.

With the arch trim removed I could see that the drain holes beneath the bonnet edge (where the wing is bolted on) are clear and drain into the void served by the plastic drainage channel/ground.

Also accessible was the test at the end of the A-pillar drain, I prodded this with a GRP mousing line, it seems clear.

That’s all I can cope with for the time being. If this doesn’t work I’m at a loss for ideas.
 

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