I already have foam at the bottom but I’m not sure if it’s enough.
The holes are easy to find if you lie on your back alongside the car with your head by the back wheel. Then stretch you arm out inwards at 90 degrees straight in in front of the wheel and turn your palm upwards, lifting your arm and bending your wrist and fingers towards you to contact the vertical panel facing away from you, Feel around and you will find the holes which face horizontally away from you with the plastic tubes slightly proud of the surface.
Another thing I have tried and which appears to help a little is to move the passenger seat right back, so that the head rest blocks the hole in the rollover hoop and the seat itself blocks the panel behind it. Subjectively, the vast majority of road noise is coming from behind and to my left, so anything between my left ear and the apparent source should help, maybe only a little but it all adds up.
Another thing that occurs to me is the windblocker. I wonder if solid windblockers make a difference and if its worth blocking the holes in the existing one.
With a properly supported car (if you can) get yourself under the car at the point where the drain exits. With a torch you can just see the drain flap up the end of the tube, if it’s stuck open or non existent you’ll obviously know. Thankfully mine are there and doing their job.
A word of warning - When you do find the hole be careful if you stick your finger up it. When I did this I discovered a sharp edge inside which took a sliver of skin off the back of my finger on the way out. I’ve seen someone else mention this on the forum too.
Just done this to my MK3 and it did make a good difference. The noise has not gone, but reduced by 50%. All these jobs being done within a month of purchase. It is going well, but still along way to go. Next job is persuade my wife that I need a new exhaust. That will hopefully get rid of the rattle under the rear of the car which definately sounds like baffles.
Thanks for this information. I’ve only had my car a few months and wasn’t sure what the noise from the roof drains and stuck valves might sound like, but having just pushed a trombone cleaner through mine this week and now read these posts, I think I may have heard the sound.
I’m going to try this foam. The linked one looks like it is probably a medium/coarse grade of 20 PPI. I’m wondering if using fine grade of 30 PPI would reduce the noise more?
It’s strange we worry about the tubes being blocked, and then stuff foam in them!
The foam is about an inch thick. I cut off a couple of pieces around 2" square and rolled each one then inserted into the drain pipes with just a bit less than 1/2" sticking out the bottom for easy removal for cleaning, so the foam was filling the area up to where the tube curves upwards to the one-way valve.
I did a test by pouring water into the top of the pipes from the roof well and they were running freely.
As I mentioned earlier, if you stick your finger up the tube watch out for a rough edge up there.
The noise which has gone was a sort of hollow mid-frequency, related to road speed in my left ear. Hard to describe without taking out the foam again and going for a drive but it has definitely disappeared.
I think the pieces I cut were more like 4x2 than 2x2 with 1/2" left proud.
I didn’t check the flow but it has rained plenty and there is no excess condensation, so all appears to be fine.
As you say, the noise in the left ear is much reduced.
It’s remarkable how directional it is.
If you can now hear a noise from a door seal that you couldn’t hear before, that’s great. It means you aren’t imagining the improvement.
Once you’ve fixed the door seal, maybe you’ll find something else you can fix lol
What foam did you use ? I use the very open celled stuff like in aquarium filters and put pieces in just big enough to stay in, if you scrunch it too tight it might give problem. My car lives outside and never had any issues, just replace them a few times a year.
I’ve used the yellow part of the scotch brite sponge, it went ok until I parked until that damn gutter
Maybe I need to give it another try with the aquarium filter type.
I was wondering If I could place some kind of noise barrier (plastic or such) just a bit over the grill on the upper part inside the cabin.
I think the water will flow under it, am I right?
lol
