Blocked sunroof drain tubes

[Justin Passing]

Honda CRV '06.
I can't clear them
I have pushed curtain wire down the 2 tubes from the sunroof gutter. They stop dead after about 4 ft, level with where the front winker repeater lights are.

I've loosened the plastic wheelarch liner and felt up to the repeater, but can't feel the end of the tube.
Honda say it "should be there" It goes down the A pillar, they say, then to a one-way valve of some kind which is supposed to stop mud and insects getting to it.

I have tried throttle (bowden) cable, in a cordless drill, and also curtain wire with the end worked to be a corkscrew. Nothing gets attached to the metal.

I have been told people use air pressure, and also been warned against using it. If the rubber tube comes off, back at the sunroof gutter, water goes into the head lining - a disaster for the car!

Does anyone know what might be causing such an obstinate block??

The curtain wire:

 

[Burnerman]

I've done these on a Toyota RAV and the arch liner had to come out completely - the outlets were higher than what you suggest on yours though but they were visible. Maybe the Honda is similar? A moon roof car will drain to the back too.
If the pipes detach, the head lining has to be dropped, so no compressed air
For my cleaning method, I used strimmer line.
John

 

[Justin Passing]

Thanks.
Some questions, if you can remember -
basically what was blocking the *** things?
Were there any end pieces, like non return valves?
What was blocking them so badly that strimmer line didn't work? I'm wondering whether some mild acid like Mr Muscle drain unblocker would do any good.
Was the end inside the "A" pillar?

To remove the arch lining I have to remove the outer trim. That unclips but has to slide back on, which means undoing the front bumper...

 

[Burnerman]

For sure, most problems I've had with these have been blocked up with crap very close to the sunroof itself - usually within a couple of cm.
I noticed with the Toyota, some of the bends in the pipe were pre formed, rather than just a length of tubing finding it's own way. Maybe that's what you are hitting?
The ends of the tube were high up, just lower than the A pillar. Sorry I don't know if there were any valves as the blockage cleared so I left it at that. This was a 60 plate car.
I wouldn't use any chemical cleaner as the blockage will likely just be moss and soil or whatever.....you don't need stained paint work or dissolved fittings!
Typical that your bumper is in the way - you could sort things quickly enough otherwise. Have you googled or youtubed this one?
John

 

[JohnD]

can you access the lower ends of the pipes, and blow up them with a cycle pump?

(an air hose might burst them)

 

[freddiemercurystwin]

What about a bicycle brake cable?

 

[Justin Passing]

can you access the lower ends of the pipes

No, that's the problem.

I think it's likely there's a formed bend in there.
I need something very bendy to shove into the end of the curtain wire, which will go round a bend. FIshin line or something. Interdental brush wire - but longer...

I may try a little air pressure!

Googled it to death - nothing precise enough, lots of ideas all the same.

 

[Justin Passing]

Bike brake cable is like the bowden cable, perhaps thinner. I can always remove a few strands and try that. A "formed" end would likely be very tight.

 

[freddiemercurystwin]

I meant the inner cable.

 

[AlanE]

I may try a little air pressure!

I would try the opposite.

Find a length of small rubber tube (or windscreen washer tube) cut straight, hold this end against drain hole and other end in wet vac hose with fist clenched to form a seal. This way of sealing will allow some form of 'adjustment' of the vacuum.

This might suck the muck back the way it came. Problem is I have seen loads of these tubes with like a valve at the outlet end formed by flattening the rubber. This can help buildup at this and of the tube.

 

[Justin Passing]

I'd tried the vac, no go. It may have sucked the tube flat.

I meant the inner cable.

Yes it was the inner cable I tried. I found some bike cable which is thinner than accelerator cable, but that stops dead too, despite twisting, and kinking the very end.

Next is to melt a piece of skinny ty-rap into the curtain spring. The leading end is pokey but flexible.

 

[Justin Passing]

The ty-rap came back with a little goo on it, but nothing much.
I used some bits with a foot pump, and a nozzle shoved into the gutter hole, and pumped to 20psi - and one side cleared. But the other wouldn't clear at 35psi. It's quite hard to hold a footpump, hand cranked against your arm with one hand, while shoving the nozzle into a hole. I didn't fancy going higher anyway.
I got most of the water out with the curtain wire (finger over the end etc to trap it). Then I got some sodium hydroxide liquid up the curtain wire, shoved that down (held it.. ...then took my finger off), so it's all at the bottom. Then I had some coffee...

It worked. 15 minutes late the gunk shot out at about 10psi. (NaOH rots organics).
Then lots of very hot water/Flash solution, & all flowing nicely.

Thanks all for the thoughts

Then footpump gripped the blue tube-grip - hence the black marks from its rubber..
A football/airbed pumping adapter would have worked, too.