Pics of top drain holes????

S

Smudgers

Member
In a nutshell my boot, my carpets, and even the fuel pump got full with water. I took everything out and couldn't replicate the problem. That's because the problem is only found when you access the top drain holes which I think can only be done by taking the roof off! There the drainage hole is tiny and once the drains are full backs up with water and any debris that has made it's way into the drainage outlets then causes it to pour in through the back and into the boot..... I guess nose down stops the water going in the boot and maybe slowly drain through the debris? When I get the car back ill try and post pics - I've had extra drain holes drilled in the plastic as my BMW stealer has done 3 or 4 of these and it's stopped the problems with no returned vehicles apparently.... Has anyone else realised this seems to be the problem not just the blocking of drain channels?

Lots of people seem to have had leaks.....
 
Please post a pic if you've taken the roof off and can show what I mean I don't have pics as my dealer is fixing it....
 
You do not have to take of the roof have a look here at the process to clean the drains : http://www.shipkiller.com/SoftTopDrains.html

Click on the pdf file.
 
You can do this job much more easily. Get a 2 foot long piece of stiff but narrow gardening wire and a jug with half a pint of water.

- Print out shipkillers pictures of the drain holes

- Go to the car, put the roof half way down

- pour the water into the well that the roof folds into (pour it down through the mechanism just behind the driver's door)

- look under the car - if water is running out onto floor just in fromt of rear wheel, then all is fine

- if no water appears, or it drips rather than runs, then carefully and slowly slide the wire through the mechanism until it gets to the bottom of the well

- start prodding around until you find the drain hole (refer to the picture that you printed earlier)

- at some point you will feel the wire going into the drain hole. Gently prod it in a few times and pull it clear. You should then see the water start running out beneath the car.

Then repeat the process for the other side of the car.

Repeat about once a month to ensure that the holes stay clear (perhaps more often when leaves are falling).

Have been doing this ever since reading about this problem when I got my car in 2006. Sometimes the holes are a bit blocked, but this soon gets them cleared and when you have the hang of it it takes about 2 minutes to do.
 
ship killers how-to is good. I did mine while the wheels were off so had easy access from the bottom. I could only really see what was going on down there on the drivers side the passenger side has the motor in the way I think.
 
I done mine weekend before last using the shipkiller guide.

Didn't remove the rear wheels but I did jack the rear end up a bit to get to the bungs. Once you've removed the inner arch trims the bug is on the underside just inside the box section, about half way between the rear wheel and the rear jack point. If you haven't done it before its easier to look from underneath to locate the bung, just look away when you pull it out to save getting all the loose debris in your eyes (like me).

And put the bung somewhere secure whilst you flush the channels. I put mine down next to me, windy day, bung blew into road and got run over, breaking the plastic part. This will save you having to fabricate a new bung :thumbsup:
 
Zmachine said:
I done mine weekend before last using the shipkiller guide.

Didn't remove the rear wheels but I did jack the rear end up a bit to get to the bungs. Once you've removed the inner arch trims the bug is on the underside just inside the box section, about half way between the rear wheel and the rear jack point. If you haven't done it before its easier to look from underneath to locate the bung, just look away when you pull it out to save getting all the loose debris in your eyes (like me).

And put the bung somewhere secure whilst you flush the channels. I put mine down next to me, windy day, bung blew into road and got run over, breaking the plastic part. This will save you having to fabricate a new bung :thumbsup:
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How important is it to put the bungs back? Surely allowing better flow of water will help prevent future blockage??
 
I would imagine someone at BMW spent a long time designing this function so I would put them back personally. I have heard of people leaving them out though
 
edderby said:
You can do this job much more easily. Get a 2 foot long piece of stiff but narrow gardening wire and a jug with half a pint of water.

...

- start prodding around until you find the drain hole (refer to the picture that you printed earlier)

- at some point you will feel the wire going into the drain hole. Gently prod it in a few times and pull it clear. You should then see the water start running out beneath the car.

...
Click to expand...

Can you do this on both sides? i thought the roof motor blocked access to the drain hole from above.
 
Smudgers said:
andysat said:
Left mine out,stupid design imo :thumbsdown:
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Yeah BMW told me today to leave them out...... No need apparently to keep them in...
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Who at BMW told you this? Was it the receptionist? The sales manager? Henry the mild mannered janitor? One thing is for sure it will not have been the qualified automotive mechanical design engineer who worked on the development of the Z4 roof mechanism.

They are there for a reason. They act as non-return valves preventing ingress of dirt from the road entering the end of the tube and drying/collecting here and causing and restricting or blocking the drain holes. They are designed in a way that they open easily when even a small amount of water pressure is presented to the upstream side of them but they then spring closed to stop mud and other detritus from the road entering the tube.

You should clean them and put them back in. They could never resist a 2 foot colmn of water in the tube behind them without opening so are never going to be the cause of water retained near your roof motor. Roof motors on Zeds fail because the motor is sited in an area where it is subjected to moisture and it's casing isn't fully waterproof. Keeping your TOP drain holes clear is the key to roof motor longevity.
 
GreyZed said:
Smudgers said:
andysat said:
Left mine out,stupid design imo :thumbsdown:
Click to expand...

Yeah BMW told me today to leave them out...... No need apparently to keep them in...
Click to expand...

Who at BMW told you this? Was it the receptionist? The sales manager? Henry the mild mannered janitor? One thing is for sure it will not have been the qualified automotive mechanical design engineer who worked on the development of the Z4 roof mechanism.

They are there for a reason. They act as non-return valves preventing ingress of dirt from the road entering the end of the tube and drying/collecting here and causing and restricting or blocking the drain holes. They are designed in a way that they open easily when even a small amount of water pressure is presented to the upstream side of them but they then spring closed to stop mud and other detritus from the road entering the tube.

You should clean them and put them back in. They could never resist a 2 foot colmn of water in the tube behind them without opening so are never going to be the cause of water retained near your roof motor. Roof motors on Zeds fail because the motor is sited in an area where it is subjected to moisture and it's casing isn't fully waterproof. Keeping your TOP drain holes clear is the key to roof motor longevity.
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Funnily enough it was the senior technician!
 
Senior Technician? What's that? I'll tell what it it isn't. It isn't a fully qualified design engineer who understands WHY it was designed that way. Does he have a Masters Degree in Engineering or an NVQ? Most of these guys are "bolt off/bolt on" component swappers not even proper time served mechanics these days.

I know I'm generalising and there may be the odd really good mechanic out there in main dealers but typically they are conveyor belt part trained technicians who know nothing more than how to follow instructions to remove and replace the parts that the documentation says will resolve the problem or fault code. Sometimes the approach works sometimes it doesn't but I don't get the impression these technicians know or even care why something does or doesn't work. They will happily put new bits in your car charge you top dollar and give it back to you with the problem still present and have no guilt or embarrassment in doing so.

If your car is under warranty fair enough you may have to go there but don't assume their advice is always good.
 
GreyZed said:
Senior Technician? What's that? I'll tell what it it isn't. It isn't a fully qualified design engineer who understands WHY it was designed that way. Does he have a Masters Degree in Engineering or an NVQ? Most of these guys are "bolt off/bolt on" component swappers not even proper time served mechanics these days.
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Hmm. Would this be the same fully qualified design engineer that designed a roof system well known to have drainage issues leading to roof motor failures?
 
Stuart Truman said:
GreyZed said:
Senior Technician? What's that? I'll tell what it it isn't. It isn't a fully qualified design engineer who understands WHY it was designed that way. Does he have a Masters Degree in Engineering or an NVQ? Most of these guys are "bolt off/bolt on" component swappers not even proper time served mechanics these days.
Click to expand...

Hmm. Would this be the same fully qualified design engineer that designed a roof system well known to have drainage issues leading to roof motor failures?
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Good point mate.
 
Stuart Truman said:
GreyZed said:
Senior Technician? What's that? I'll tell what it it isn't. It isn't a fully qualified design engineer who understands WHY it was designed that way. Does he have a Masters Degree in Engineering or an NVQ? Most of these guys are "bolt off/bolt on" component swappers not even proper time served mechanics these days.
Click to expand...

Hmm. Would this be the same fully qualified design engineer that designed a roof system well known to have drainage issues leading to roof motor failures?
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Ha ha - I didn't say the design was perfect in fact the siting of the roof motor is clearly not ideal when coupled with the non water tight nature of its casing but my point is simply to consider advice in the context of the competence of those who offer it. BMW main dealer technicians should not give advice if they are not qualified to do so. There is no way leaving the rubber NRV grommet out of the bottom end of the drain tube will help prolong the life of the motor. If anything it is more likely to become blocked as that is in fact why the little valve is there in the first place.

The roof mechanism overall is actually quite a remarkable piece of engineering and even though mine is nearly 10 years old it goes up or down in only 6 or 7 seconds. Even by today's standards it is very quick and very neat for an electric hood. As you say though it is a shame it was spoilt by restrictions on the siting of the motor leading to the inherent water ingress issue.
 
When i removed my 'bungs' one side had small oval leaves stuck in the cross slit which i am sure would have fallen straight through had the bung not been there :roll:
 
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