Fred Smith

Focus Mk3 boot leak

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Can anyone help. I have a leak in the boot of my Mk3 Focus. I have traced where the water enters the boot compartment to an access hole to the left of the near side wheel arch (small hole above the cables in the photo) but I'm not sure how it is getting into the compartment between the inner and outer skins. Can anyone tell me where the water is entering the bodywork from the outside.

IMG_3594 - Copy.JPG

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Usually the light cluster or air vent.I've a mk1 so I expect someone with a mk3 will have a better idea.

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The problem will most likely be caused by the air vents behind the rear bumper. This is a known problem of the Focus MK3. Rain water leaks between the vents and the bodywork. When this happens the water collects in double sided compartments below the boot. When driving/steering/braking the water is pushed from side to side inside the compartments and also upwards. When the water is pushed upwards it enters the boot through several small holes.

To determine if this is the problem you can remove the rubber plugs of the compartments. These are located at the bottom of the car near the rear bumper. The compartments can contain up to 10 Liters of water each so be prepared to get wet.

To completely solve this problem the rear bumper needs to be removed. Next the air vents can be removed. When the air vents are removed you have access to the compartments and the sound insulation material inside. Both the compartments and the sound insulation material must be dried before the vents are installed and sealed.

 

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Thanks JW1982 for a comprehensive answer. What you have described sounds like it could well be the problem on our car. Can I ask, how do you seal the vents? And don't the vents need to be able to ventilate the compartment? Surely the vents are there for a reason?

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The vents have rubber flaps which open to release excessive air pressure inside the car. For example when closing the doors or when the interior ventialtion fan is on. 

The vents have a rubber/plastic lip at the outside which in theory should form a seal between the vents and the bodywork. However in practise the rubber/plastic lip does not seal properly. This allows rain water to leak between the vents and the bodywork. 

To solve this problem the vents need to be removed. This is mainly needed to clean the contact surfaces of both the bodywork and the vents. After cleaning the vents can be reinstalled using a proper sealant. You only have to apply sealant between the rubber/plasic lip of the vents and the bodywork. The rubber flaps remain untouched. You can basically use any type of sealant as long as it is waterproof. I personally use an automotive PU sealant that is used to seal bodywork but any generic silicone (neutral cure) will be fine. 

 

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Many thanks JW1982 for your help. Will try this fix and hope it sorts the problem. Will let you know.  

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There is a most excellent thread byhttp://www.fordownersclub.com/forums/topic/70704-possible-mk3-boot-leak//URL]

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On ‎12‎/‎08‎/‎2017 at 4:32 PM, JW1982 said:

The problem will most likely be caused by the air vents behind the rear bumper. This is a known problem of the Focus MK3. Rain water leaks between the vents and the bodywork. When this happens the water collects in double sided compartments below the boot. When driving/steering/braking the water is pushed from side to side inside the compartments and also upwards. When the water is pushed upwards it enters the boot through several small holes.

To determine if this is the problem you can remove the rubber plugs of the compartments. These are located at the bottom of the car near the rear bumper. The compartments can contain up to 10 Liters of water each so be prepared to get wet.

To completely solve this problem the rear bumper needs to be removed. Next the air vents can be removed. When the air vents are removed you have access to the compartments and the sound insulation material inside. Both the compartments and the sound insulation material must be dried before the vents are installed and sealed.

 

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Hi,

Is there any chance you could repost the pictures from this post last August.

I am having the same problem with the leak in the boot and I think it would be helpful in solving my leak.

Thank you.

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Capture.PNG.e50163e3f37a3c06e612d84a3c7a5008.PNG

Would it be these vents? Are they only accessible by taking the bumper off?

Thanks

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Yes  there could be potentially water ingress at those air vents.If so pop them out and silicon around👍

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I can see the photos now. Its a big help.

Was looking in my boot yesterday and its only on the near side which I guess is good. Think I will remove the bumper and do as you suggested on both sides.

I don't quite understand the 3rd picture with the 4 bits circled. Do these need to be sealed to?

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Again possible places to look for water ingress.

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On 8/12/2017 at 4:32 PM, JW1982 said:

The problem will most likely be caused by the air vents behind the rear bumper. This is a known problem of the Focus MK3. Rain water leaks between the vents and the bodywork. When this happens the water collects in double sided compartments below the boot. When driving/steering/braking the water is pushed from side to side inside the compartments and also upwards. When the water is pushed upwards it enters the boot through several small holes.

To determine if this is the problem you can remove the rubber plugs of the compartments. These are located at the bottom of the car near the rear bumper. The compartments can contain up to 10 Liters of water each so be prepared to get wet.

To completely solve this problem the rear bumper needs to be removed. Next the air vents can be removed. When the air vents are removed you have access to the compartments and the sound insulation material inside. Both the compartments and the sound insulation material must be dried before the vents are installed and sealed.

 

20160129_192904_zps2jftydp6.jpg~original

20160129_192913_zpspqwwmfst.jpg~original

 

20160129_192924_zpsshprxs5i.jpg~original

20160129_204736_zps6hrepdow.jpg~original

20160129_204820_zpsmofvgzmx.jpg~original

 

 

 

 

Hi, I believe I have the same problem with the vents leaking and thus allowing water into the boot - I know this might be a silly question but I shall ask it anyway, if by taking out the rubber plugs below the rear bumper it lets all the water of the internal compartment out thus stopping it splashing around into the boot - why not leave the rubber plugs out and stop the internal compartment filling up with water ?

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On 3/28/2018 at 5:46 PM, Alan333 said:

Hi, I believe I have the same problem with the vents leaking and thus allowing water into the boot - I know this might be a silly question but I shall ask it anyway, if by taking out the rubber plugs below the rear bumper it lets all the water of the internal compartment out thus stopping it splashing around into the boot - why not leave the rubber plugs out and stop the internal compartment filling up with water ?

Alan, leaving those bungs out would allow water in as they are right behind the rear wheel. It's essential to try and stop water getting in at all, not simply to allow it to drain away once it does get in.

 

Incidentally I had exactly this problem with my 2012 Focus, and I've made a short video showing the process of identifying and fixing it. Although JW1982's pictures show exactly where the problem is, this might help with the more detailed explanation of how to fix it. Hope it's useful for some.

 

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Mine was only leaking into the boot at the near side but when I took it apart it was very wet in both sides. I've just sealed the vents but also sealed around the two lozenge shaped bungs which are forward and above the side vent as neither of those felt like a good seal.

The side vents seam to the the main problem ones as water runs down the roof gutter then down the channel under the tailgate and behind the rear light cluster and then straight over that vent.

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