Rear sunroof drain blocked

Hi,

I have a Cx-5 2012 model with sunroof. It seems my rear right drain hole is blocked and when it rains the rear passenger footwell fills up with water.

I’ve checked the front drains and they drain ok but I can’t seem to access the rear ones. Does anyone have any photos or diagrams on how to access the drain holes from either the sunroof end or the underside of rear bumper where it seems they drain out?

i dont want to have to remove any major parts like inside roof lining or rear bumper if possible.

thanks
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Hi,

I have a Cx-5 2012 model with sunroof. It seems my rear right drain hole is blocked and when it rains the rear passenger footwell fills up with water.

I’ve checked the front drains and they drain ok but I can’t seem to access the rear ones. Does anyone have any photos or diagrams on how to access the drain holes from either the sunroof end or the underside of rear bumper where it seems they drain out?

i dont want to have to remove any major parts like inside roof lining or rear bumper if possible.

thanks
Here’s another sunroof leak problem on the CX-5? This gives me the bad memory of trying to deal with the sunroof leak problem on my previous 2001.5 VW Passat!

Most of time the leak is coming from the front 2 drains. And the leak usually is caused by the drain hose which is out of position or dislodged from the drain hole on top or drain hose joint down to the outside body. If the drain is clogged, you have the other 3 to let the water accumulated in the tray drain. In other words, clogged sunroof drain will cause minimum leak into the interior. If you see water accumulation on the interior floor, either the drain hose is dislodged from the drain hole on top, or from the drain hose outlet joint if the joint location is located inside of the car body like my VW Passat does. The reason for the drain hose dislodged is due to the heat or degrade of the rubber hose over time, and it works in its way to loose from the drain hole or drain hose joint.

Here is a diagram of the sunroof assembly showing the hose parts but not where they’re attached on CX-5. The drain holes should be in all four corners of the sunroof tray. They’re difficult to reach for the rear 2, you may just have to take the headliners down and check the rear drain hose connections. #16 is the front drain hose and #17 is the rear. #18 is the front drain hose joint and #19 is the rear drain hose joint.

3C958518-89DA-4288-814E-C67C5BB5F899.png


And here’s a sunroof diagram from a CX-7. The front drains run down in A pillars and the rear drains run in down in C pillars. CX-5’s should be similar.

CE907C8D-2C8C-4901-A2B5-5A4D9E1DF563.jpeg
 
Here’s another sunroof leak problem on the CX-5? This gives me the bad memory of trying to deal with the sunroof leak problem on my previous 2001.5 VW Passat!

Most of time the leak is coming from the front 2 drains. And the leak usually is caused by the drain hose which is out of position or dislodged from the drain hole on top or drain hose joint down to the outside body. If the drain is clogged, you have the other 3 to let the water accumulated in the tray drain. In other words, clogged sunroof drain will cause minimum leak into the interior. If you see water accumulation on the interior floor, either the drain hose is dislodged from the drain hole on top, or from the drain hose outlet joint if the joint location is located inside of the car body like my VW Passat does. The reason for the drain hose dislodged is due to the heat or degrade of the rubber hose over time, and it works in its way to loose from the drain hole or drain hose joint.

Here is a diagram of the sunroof assembly showing the hose parts but not where they’re attached on CX-5. The drain holes should be in all four corners of the sunroof tray. They’re difficult to reach for the rear 2, you may just have to take the headliners down and check the rear drain hose connections. #16 is the front drain hose and #17 is the rear. #18 is the front drain hose joint and #19 is the rear drain hose joint.

View attachment 234395

And here’s a sunroof diagram from a CX-7. The front drains run down in A pillars and the rear drains run in down in C pillars. CX-5’s should be similar.

View attachment 234394

hi,

thanks for that. I’ve tested all the drain holes and it’s definitely the rear right one that the water is not flowing through. The others are all draining well.

If I could just get to the rear hole to run some wire into it and check for blockages would be ideal but looks like I might have to take the whole lining down inside to check the connectors.

Mazda service wants to charge me $500 just for ‘analysis’ of the problem. Would like to attempt it myself instead.
 
:
Virginia
:
2021 CX-5 White
I would be careful with wire in case you pierce the hose. You need to research this, but I heard on the radio that the time honored solution is to blow it out with compressed air. I imagine you would use the attachments I have circled in red, or possible one of the smaller attachments.

1609902943103.png
 
Thanks Chas,

yeah I was thinking about using either plastic trimmer line or compressed air can to blow but again the issue is reaching the rear holes of the sunroof as they aren’t visible or accessible like the front holes.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Thanks Chas,

yeah I was thinking about using either plastic trimmer line or compressed air can to blow but again the issue is reaching the rear holes of the sunroof as they aren’t visible or accessible like the front holes.
From the experience working on the sunroof drains on my VW Passat, plastic trimmer line will not be strong enough. I used the 75Ω coaxial cable to go through the drain tube, but the best is to use compressed air. But that’s easy to say than done like you said for the rear drain holes because you just can’t see them.

I still believe you have disconnected drain tubes either at top side drain hole nipples or at the bottom side to the drain hose joints. A clogged drain hose won’t give you flooded water on rear passenger footwell. It could also be from front drains too. The leaked rain water from disconnected front drain tube can go under the carpet and accumulated on the rear passenger footwell which is the lowest point on the floor. That’s exactly what happened on my VW Passat.

How did you find out the RR drain is clogged? Did you just pour water into the sunroof tray and see there’s no water coming down to the ground at the RR side? If this’s the case that the RR drain is clogged, the water in sunroof tray still can be drained by the other 3 and you shouldn’t see much water getting into the interior. And a dislodged drain hose at RR can let a lot of water leak directly onto your interior floor, and no water can be seen to the RR ground.

Looks like taking the headliners down is inevitable.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
I have a Cx-5 2012 model with sunroof.
If I remember if correctly, there’s no 2012 MY CX-5 for US market. North American CX-5 debuted at the November 2012 Los Angelrs Auto Show, although Mazda North American Operations had started selling some 2013 CX-5’s in 2012.
 
From the experience working on the sunroof drains on my VW Passat, plastic trimmer line will not be strong enough. I used the 75Ω coaxial cable to go through the drain tube, but the best is to use compressed air. But that’s easy to say than done like you said for the rear drain holes because you just can’t see them.

I still believe you have disconnected drain tubes either at top side drain hole nipples or at the bottom side to the drain hose joints. A clogged drain hose won’t give you flooded water on rear passenger footwell. It could also be from front drains too. The leaked rain water from disconnected front drain tube can go under the carpet and accumulated on the rear passenger footwell which is the lowest point on the floor. That’s exactly what happened on my VW Passat.

How did you find out the RR drain is clogged? Did you just pour water into the sunroof tray and see there’s no water coming down to the ground at the RR side? If this’s the case that the RR drain is clogged, the water in sunroof tray still can be drained by the other 3 and you shouldn’t see much water getting into the interior. And a dislodged drain hose at RR can let a lot of water leak directly onto your interior floor, and no water can be seen to the RR ground.

Looks like taking the headliners down is inevitable.

Thanks for that. Yes I tested each hole separately by pouring small amount of water in each corner. My driveway slants back so when it rains I notice the water in RR footwell. When I reverse park and car slants forward then no water in car (front or rear).