Since I bought my L494 in Feb it’s emptied the rainwater on the roof onto my right arm through the open driver’s window on the first corner I drive around after leaving home.

The sunroof drains into the rear wheel arch on both sides. If you take off the rear quarter interior panel
On each side you can see the drain tube and can gently remove them from where they meet/exit to the exterior through the bodywork.

You can then insert an air line and - very gently at first to avoid blowing the pipe off its connector at sunroof level - blow up through the tubes and hopefully you’ll hear a satisfying pop and gush of air coming from half way along each sunroof rail.

Literally a 5 minute job.

If you have “rear climate” like I do, it’s a little more fiddly on one side but you can disconnect the fan’s exit pipe (will make sense when you look at it) and reach the tube plug behind it.

Hopefully this is helpful! 2014 L494 V8 s/c Autobiography Dynamic

Im sure mine are blocked as well but as I never open my windows unless to pay at a barrier, it has not been a big issue.
Rather than remove trim, does anybody know how easy it would be to use a thick fishing line to do the same job? Assuming of course the entry/exit point is accessible. RRS HSE Dynamic SDV6 2014

Nemo mortalium omnibus horus sapit

I doubt it fishing line will do the job but i know that grass trimming line will do it for you....it worked for me okay.

Off to my shed, I think I have a reel somewhere! Thanks! RRS HSE Dynamic SDV6 2014

Nemo mortalium omnibus horus sapit

Had a leaky sunroof last week with the heavy rain.
Found it was the rear passenger corner - you can do it from the top - you just need to pop off the black gloss plastic trim that runs along the sunroof as thats where the drains are - mine was full of leaves/seeds.

Punkawallah wrote:

Since I bought my L494 in Feb it’s emptied the rainwater on the roof onto my right arm through the open driver’s window on the first corner I drive around after leaving home.

The sunroof drains into the rear wheel arch on both sides. If you take off the rear quarter interior panel
On each side you can see the drain tube and can gently remove them from where they meet/exit to the exterior through the bodywork.

You can then insert an air line and - very gently at first to avoid blowing the pipe off its connector at sunroof level - blow up through the tubes and hopefully you’ll hear a satisfying pop and gush of air coming from half way along each sunroof rail.

Literally a 5 minute job.

If you have “rear climate” like I do, it’s a little more fiddly on one side but you can disconnect the fan’s exit pipe (will make sense when you look at it) and reach the tube plug behind it.

Hopefully this is helpful!

Just a word of warning, the sunroof drains holes have a small stubby pipe that the hose connects to. This pipe is prone to corrosion, causing the rubber drain hose to become detached and water to run down the roof lining. potentially causing mayhem with electrical systems.
There are a number of threads on this subject, I suggest a good read.
Its a relatively easy and inexpensive fix. RRS HSE Dynamic SDV6 2014

Nemo mortalium omnibus horus sapit

I wonder if the extended warranty would cover the electrical damage! You’d think they would have modified the pipe in its early stages once it became apparent there was a fundamental problem