Noisy roof drains. MK3

Evenin all, Since I’ve owned this car it’s had a lot of noise coming from the rear of the cabin with the roof up. I can almost hear everyone reading this muttering that the valves are stuck open in the drains. They are/were. I’ve prodded and poked, stuck the trombone cleaner through them in the correct direction multiple times to no avail. So I followed a little piece of advice I found on another website. Aquarium foam. This stuff is designed to allow water through but not anything else [like fish presumably]. I bought a 2ft square piece and cut a couple of small chunks off. Inserted into the bottom of the drains and the noise is gone. The water still flows well through the foam and when i need to clean the tubes they pop in and out easily.

Hopefully that’s of some use to somebody!


That’s what i have done and eliminated my noise as well. I just renew the foam every few months.

I’m glad I read this link, as I have had the same problem since I’ve owned my MK3, although I new what the problem was, after using trombone brushes and all that, but when my wife complains about the road noise, I blame the soft top, or turn the CD player up.
I’ll be buying some of the aquatic foam this weekend :blush:

Something that I’ve intended doing for about two years.
I placed carpet underlay under the boot carpet, behind the plastics, on the rear bulkhead and shock turrets.
I had the large plastic trim out from behind the seats and placed underlay on the floor, over the fuel tank and adhereed to the underside of the hood carrier.
Still the noise was there.

Mine is a summer toy, very very rarely driven with the roof up, and whilst I have some foam to insert, I just havn’t gotten around to it.

Well you have a pretty well insulated car now, which should stop most other noises and rattles, It’s funny how sometimes a simple tip can make a big difference, I’ve had old sports cars and motorcycles in the past, I got used to a bit of wind/road noise, but my wife will definitely appreciate it , you cant beat a quick and easy fix !


That’s a good idea, I might give that a go.

So you’ve put this at the end of the pipe by inserting it from underneath the car?

I did this a few days ago after cleaning out the vents - that was more of a faff than it should have been but created a lot of road noise. Bunged some foam in the tubes from underneath and its much quieter now. I’ll get some of the aquatic stuff to replace it with, good idea. thanks

Ady, just cut a piece big enough to scrunch up a little, insert it into the end of the drain under the car and leave 1/2" or so hanging down to extract it at some time. I then slowly poured some water from above to make sure water runs out ok.


Thanks Rich, i’ll do just that. :+1:

THANK YOU so much, it sure is useful to me and I am going to try that. When I collected my Mazda last week I could not believe the noise I was getting from one corner behind the passenger seat, couldn’t hear the wife talking - no bad thing!

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Thank you very much for this advice. I’m new to MX5s and wondered what the noise was. All fixed now and the ICE is not irritating the neighbours anymore. Also bought some trombone brushes to clean them out. I’ve now added this to my quarterly maintenance plan.

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Great idea, tried the trombone rod, spent hours trying to locate the entry hole to the drain with no luck so the trombone rod is now 14 feet up in the air swinging from next door’s telephone line. Read your advice which has helped reduce the noise a bit so ordered more to pack-out the entire area under the plastic vent to see if that works, also packed the underside drain hole as well. Thank you so much.

Just done this and it makes a massive difference.

The other thing to check is that on the MK3.5 and MK3.75 they have additional foam at the top as well. MX5 parts do a kit for MK3

On my MK3.5, I had made the mistake of using the trombone cleaner the wrong way, pushing the two little rubber flaps up and they got stuck. I bought a cheap wireless endoscope from Amazon and with a bit of faffing got them corrected. Takes a little while to figure out what you are looking at as the flaps sit on little cross bars that hold them in place. One is right at the top and the other near the bottom.

I have ordered some of the aquatic filter foam from the link listed here but it turns out to be coming from China, so could be some time…
Meanwhile, I am having trouble finding the bottom end of the drain tubes on my 3.5 roadster.
Could someone please give me a really good description of how to find them please?
Eg, which way do they emerge from - the front, rear, inside or outside and how far from the nearest point on the outside of the car? What is that nearest point??

Many thanks.

The bottom of the drains is located in front of the rear wheels facing towards the centre of the car. If you lay by the side of the car and run your hand up the inside of the frame in front of the back wheels there is a round hole, just above that there is an oblong hole with rounded edges that the plastic of the drain tubes protrude from. I’ll post a pic if I get the chance

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Not a huge amount of help but I’m at work and it’s dark out here!

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That’s really kind, thanks.

Will take a look tomorrow. :slight_smile:

Similar view, where BBB said, but without the underseal hiding everything,

Driver’s side just now

Passenger side (pic from years ago)

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Thank you.

I have looked at lots of pics and even videos but it was well worth asking the question, as it’s really difficult to get the orientation right and obtain a clear idea of exactly where to look and feel for these outlets,

Thanks guys!!

The underseal does make it hard to take photos. I never realised how bare they left the factory though. I had the underseal done a couple of weeks after getting the car so never really saw it naked.

When I access the holes I lie next to the car with the rear wheel next to my head and my feet towards the front. From there i can stick my arm up into the void behind the seats and feel the drain from there. It’s about 1/2 a forearm length from the bottom of the car.

I stated that the holes were oblong earlier, that was sloblock. They’re round

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