heater box drain

bazza1967

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mercedes sl 350 2007
hi guys what is the best way to clear the drain in the heater box on a sl350 2007 as ive read on the forum that this can cause condensation inside and iam pulling me hair out. bought the car 4 months ago love it. but this is a pain even bought a top class cover to try n sort it breathable of course. thanks barry
 

Mr Greedy

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E350/2011/OM642 265bhp
For most cars (including my 2004 W203 C class and my currect 2011 W212 E350) I'm afraid if the box is full of rotten leaves and filth and dust, there is no substitute for a wet vac, a long flexible crevice tool for the vacuum, and a variety of long bottle brushes and long 'fish tank' style pipe cleaners.

Unfortunately to get the to offending box, I have found the most effective way is to remove the windscreen wipers and remove the scuttle panel, providing excellent access. you would need a puller to remove the wipers. Mark on the windscreen with a suitable marker where the wipers sit now. Removal of wipers and scuttle panel isn't that difficult or time consuming. Watch youtube for some tips. Probably any Merc vids will give you the general idea.
When putting the wipers back on, torque the nuts up to spec, as it's easy to over tighten and snap of a wiper arm shaft (ask me how I know).

You might get lucky by poking fish tank style pipe cleaners or robust garden wire up the drain holes in or around the wheel arches, in combination with trying to carefull flush water through from the top by pouring into the scuttle panel. It depends how much rubbish there is clogging up the box.

And I think it's not the heater box that fills with water; it's the scuttle box/drain channel infront of the heater box at the bottom of the windscreen that is usually the issue. Whereby it blocks, fills and overflows into the heater box.

May be other can offer specific SL350 help.

Good luck.
 
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bazza1967

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thanks for the help mr greedy its appreicated i think its going trial and error.
 

SL63 Mark

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R231 SL63 AMG
On the R230 SL you need to remove the near side inner wheel arch and remove the heater box rubber drain nozzle. That is the only way to ensure the heater box does not fill with water. This leads to water seeping into the car via the passenger footwell. You should check whether you have water under the carpets, which can cause the delicate electrical connectors to corrode and you may start experiencing electrical issues.
 

SL63 Mark

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Your Mercedes
R231 SL63 AMG
For most cars (including my 2004 W203 C class and my currect 2011 W212 E350) I'm afraid if the box is full of rotten leaves and filth and dust, there is no substitute for a wet vac, a long flexible crevice tool for the vacuum, and a variety of long bottle brushes and long 'fish tank' style pipe cleaners.

Unfortunately to get the to offending box, I have found the most effective way is to remove the windscreen wipers and remove the scuttle panel, providing excellent access. you would need a puller to remove the wipers. Mark on the windscreen with a suitable marker where the wipers sit now. Removal of wipers and scuttle panel isn't that difficult or time consuming. Watch youtube for some tips. Probably any Merc vids will give you the general idea.
When putting the wipers back on, torque the nuts up to spec, as it's easy to over tighten and snap of a wiper arm shaft (ask me how I know).

You might get lucky by poking fish tank style pipe cleaners or robust garden wire up the drain holes in or around the wheel arches, in combination with trying to carefull flush water through from the top by pouring into the scuttle panel. It depends how much rubbish there is clogging up the box.

And I think it's not the heater box that fills with water; it's the scuttle box/drain channel infront of the heater box at the bottom of the windscreen that is usually the issue. Whereby it blocks, fills and overflows into the heater box.

May be other can offer specific SL350 help.

Good luck.
Hi Mr. Greedy, this is not necessary on Bazzas car. The R230 SL is different to the C class and E class. You can access the drain box via the inner wheel arch. All you need to do is remove the drain nozzle, and heater box will no longer collect water. I have heard of many of these being done, and no-one has ever had to remove the wipers. I did mine a few years ago. Have you heard differently ?
 

Mr Greedy

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E350/2011/OM642 265bhp
If that's an easy route, then that's good knowledge.

My experience has been with the C and E. I sucked loads of rubbish particularly out of the scuttle drain on the E class. It's not.a big job to remove the scuttle, but if it's not needed for the SL that's a result
 
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bazza1967

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mercedes sl 350 2007
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On the R230 SL you need to remove the near side inner wheel arch and remove the heater box rubber drain nozzle. That is the only way to ensure the heater box does not fill with water. This leads to water seeping into the car via the passenger footwell. You should check whether you have water under the carpets, which can cause the delicate electrical connectors to corrode and you may start experiencing electrical issues.
thanks mark i will give it a go at the weekend
 

rexemper

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Your Mercedes
R230 SL500 - oh yeah!
I did mine ages ago and the heater box has been bone dry ever since. I left the bung out in the end - mainly as I couldn't fit it back in! - but in hindsight, its meant that the box has stayed dry.

Relatively simple job if you have a jack so you can get the wheel off.
 

flowrider

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SL500 (R230)
The airbox grille on the R230 let's a lot of muck fall in which blocks the drain so I have fitted a 2mm plastic mesh over the existing grille which allows the air to pass unhindered but stops all but the smallest muck from falling in.
 
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