OK DUMB QUESTION ALERT. Yes dear reader I am surprisingly more than capable of generating dumb questions.
After several years of owning a soft top Mk 2.5 NB I am familiar with the process of cleaning the roof drain tubes. Having recently acquired a Mk 3.5 NC with retractable hardtop I just wondered if this also has roof drain tubes that need cleaning. I have looked carefully without success to find them. The drivers handbook is amazingly devoid of mention of them, so do I conclude that that is a job I no longer need to worry about?
If there are roof drain tubes, then any guidance on how to find them would be greatly appreciated.
Roof drains eventually depart via a plastic tube on each side containing a non-return flap to keep out the road noise.
Here’s a pic of the one behind the driver’s seat. There is a grille behind the seat which collects the water from various tubes depending on soft top or PRHT. Search the forum for many threads on the topic of keeping the drain clear by only ever rodding down from the top (trombone cleaner), never up from below (which damages the flaps), also noisy drains (damaged/stuck flaps).
I also had a similar issue recently with finding the start of the tubes where the roof sits… After about 15 minutes of poking around I gave up.
If you go under the car and look on the inside of the tub for the outlet as RichardFX said above, you’ll be able to feed your pipe cleaner from bottom to top instead and therefore it will reveal the exact place that the cleaner needs to go in from at the top of the car… Makes life way easier.
Once you’ve cleaned them, pour a decent amount of water into the drain channels to flush the remaining bits of muck out… I was surprised at how much more mud came out after I’d already cleaned them with a trombone cleaner
Yes, the flap at the bottom is a one-way flap, designed to open downwards (to let water out) but not open upwards (thereby keeping the dirt out).
When I had my soft top it took a lot of poking around at different angles to find the drain holes. They are there, pretty much at the end of the plastic ‘catchment’ close to the seats. I’m sure someone will be able to put up a photo.
Here’s some pictures.
Rubber tube (with orange marks) from PRHT rain channels going through into drivers side collection area, picture taken through cubby-hole opening behind seat
The grating and filter are an improvement applied to 2008 cars and onwards.
The official 2007 doc from Mazda for clearing softtop drains and applying modified valves and a filter is 09-001-07-1736a.pdf (google search will find it)
It does not show what I have in my 2008 NC, but it does how how all the drain pipes go together.
I sometimes use a borrowed wet-vac to clean out the tubes from underneath the car.
EDIT.
Here is an annotated picture of the driver’s side after vacuuming
The grates can’t be removed as they’re fixed with plastic rivets rather than removable screws.
When I was trying to sort mine last year I couldn’t find anything that was thin enough and rigid enough to get past the first few inches so resorted to a blast off the Karcher. If you go down that path, very short blast on very low power.
My method of choice now is a piece of hose pipe with a funnel in the top fixed to a 2ft length of narrow batten. Then pour hottish water in directing it at the grill to avoid spilling it - you shouldn’t be able to overwhelm the grill and hot water persuades most congealed crap to dislodge.
Should have added that you need to open the deck first !
I do something similar, open the roof and stop when halfway so grids are visible and use a plastic 2 litre milk carton with hand hot soapy water poured in slowly
Having progressed through 2 x Mark1s, a Mark 2.5 Phoenix, and now a Mark 3, I have a bit of experience with drain holes, and the Mark 1 was the easiest by popping a net curtain wire down the hole regularly. But the Mark 3 - AAARRGGHHH!!! However, a terribly lovely chap called Bill Woodward in S Carolina posted this on an American forum, and it is spot on. So for future reference, hope this helps…
As an aside, if it’s a bad blockage, the trombone cleaner might not work, nor the net curtain wire, so I ended up sticking an unfurled wire hanger gently down the hole, then whacking it around a bit before he water pours out of the bottom.
I agree, had my NC 7 years and only managed to find one sides drain hole in that time. No worries as my roof drains were free flowing up until last year, one had slowed up compared to the other.
A few failed attempts and I managed to locate both tubes.
Swearing helps after everything else fails.
The gratngs in my folding hardtop nc2 pop out and clip back In again with no problem.
Just pop the gratings out by tugging at the forward straight edge with your fingertips and the hole is right there.
There are two moulded in 'rivets’in the grating but they engage again when you push down on the grating to clip it back into place. They seem to work a bit like poppers.
Look at Richards pics of the drain gratings, they are the same as my nc2.
If you tug at the forward straight edge with your fingertips, they will pop right out, revealing the drain hole beneath.
They will also clip right back into place.
