Sunroof drain things.

rich1068 · June 2, 2018

Sunroofs are a bit of a new thing for me. Haven't had one for years and how I've got two!

The seal where the sunroof meets the roof was a bit misshapen on the RX and I've refitted it and all seems to be good. However, it was a little damp around the mechanism and for piece of mind I think I should check the drainage. How does one go about this? I assume the drainage holes are the two located in each front corner?

rich1068 · June 3, 2018

Anyone?

I don't want to go pouring water where I shouldn't or poking about with bits of bent wire and create a problem that didn't exist before.

sorcerer · June 3, 2018

Our RX300 had a sun roof, as does our RX450h but we never open them, preferring instead to use the climate control. However, I do know that this has been covered in the past, including the diagrams, so do a search of this forum and hopefully you should find the info you need.

Jaystar77 · June 3, 2018

There's two drains at the front and two at the rear of the frame. I struggled accessing the rear ones but if you open the roof fully and pour a small amount of water into the drain channel you should see it exit the vehicle at the bottom of both A-pillars (behind the front wheels) and below either side of the boot (behind the rear wheels). Bear in mind that the gradient the vehicle is sitting on will determine what flows where.

To check mine were clear I used thick soldering wire and pushed it down each drain pipe. The rear ones were impossible to find inside the roof cartridge so I reversed the wire and went from the drain holes up to the roof instead. I think they are a one piece tube so there shouldn't be any connections to disrupt but be careful.

Happy hunting!

PCM · June 3, 2018

5 hours ago, sorcerer said:

Our RX300 had a sun roof, as does our RX450h but we never open them, preferring instead to use the climate control. However, I do know that this has been covered in the past, including the diagrams, so do a search of this forum and hopefully you should find the info you need.

rich1068 · June 3, 2018

Thanks guys. Appreciated.

10 hours ago, sorcerer said:

Our RX300 had a sun roof, as does our RX450h but we never open them, preferring instead to use the climate control. However, I do know that this has been covered in the past, including the diagrams, so do a search of this forum and hopefully you should find the info you need.

Up until recently I was exactly the same. Haven't ordered or had a car with a sunroof since probably the mid 90s then two in a row and I open them at every opportunity!

Ezzie · October 18, 2019

On 6/3/2018 at 11:46 AM, Jaystar77 said:

To check mine were clear I used thick soldering wire and pushed it down each drain pipe. The rear ones were impossible to find inside the roof cartridge so I reversed the wire and went from the drain holes up to the roof instead. I think they are a one piece tube so there shouldn't be any connections to disrupt but be careful.

Happy hunting!

Jaystar 77, can you tell me where the drain holes at the front and back exit from the car to the ground? I know my passenger side drain is blocked and the car's at the mechanics. He can't find any drain holes so any guidance would be excellent. I'm going to him tomorrow morning to see if we can bottom it out... Apologies I've posted on a couple of threads to increase the chance of a response... I'm so frustrated, every time it rains [I live in the Lake District!], I'm cussing the darn car...

Herbie · October 18, 2019

This may help (it's for a USA RX330 but they're basically the same body shell) but if not, there seems to be a fair amount of possible info available by doing a Google image search for "RX400h sunroof drain" (without the quotes) which is how I found this:

https://www.clublexus.com/forums/rx-2nd-gen-2004-2009/648923-sunroof-moonroof-leak-2.html

surfinshark · June 20, 2020

Hi there - these diagrams helped me find my problem so thanks very much. My issue was with the rear drainage on the sunroof which was causing water to drip down the rear pillar and into the rear passenger footwell (especially when the car was facing uphill!)

I had to locate the bottom of the pipe which is behind the rear wheel arch and I discovered it had a kink in it stopping the water. Released the kink and boom! all gone. Bit of tape to reinforce the wall and stop it happening again and hopefully all sorted. Getting to the bottom hose here pretty easy...

Images attached!

Barry14UK · June 20, 2020

"Our RX300 had a sun roof, as does our RX450h but we never open them, preferring instead to use the climate control.................."

The seal you see from on top of a sunroof (moonroof) does not completely prevent water/dirt getting into the cassette so it makes sense to slide the glass back every once in a while to clean and ensure drain holes are free. I have recently removed the cassette from an old BMW I was breaking for parts and due to having not been used for a long time the drive mechanism had seized and the glass could not be moved using the motor or by manually winding back with emergency tool provided for this purpose. There was also a lot of hardened and dirty grease/some corrosion that was making it difficult to move the components. (Some now favour a dry lubricant rather than grease but I tend to use what the manufacturer used). So don't assume that by not using a sunroof you will necessarily avoid any blockages and the next owner may want to open it and it may be seized through lack of use/attention.

Lager shandy · June 20, 2020

If you want to check a pipe for blockages try thick plastic strimmer wire just melt the end into a ball shape and bit of silicon grease to aid insertion .

The-Acre · June 20, 2020

6 hours ago, Barry14UK said:

"Our RX300 had a sun roof, as does our RX450h but we never open them, preferring instead to use the climate control.................."

The seal you see from on top of a sunroof (moonroof) does not completely prevent water/dirt getting into the cassette so it makes sense to slide the glass back every once in a while to clean and ensure drain holes are free. I have recently removed the cassette from an old BMW I was breaking for parts and due to having not been used for a long time the drive mechanism had seized and the glass could not be moved using the motor or by manually winding back with emergency tool provided for this purpose. There was also a lot of hardened and dirty grease/some corrosion that was making it difficult to move the components. (Some now favour a dry lubricant rather than grease but I tend to use what the manufacturer used). So don't assume that by not using a sunroof you will necessarily avoid any blockages and the next owner may want to open it and it may be seized through lack of use/attention.

We've mentioned this before on the LOC, parts that are designed to move should be used regularly. My parking brake is a fairly useless affair but a couple of times during the week I apply it, just to keep things moving.

AWF · June 20, 2020

Having just stripped out the rear of my 2007 RX400h to find that none of the photos here matched the hose layout on my vehicle. I had water in rear near side. Firstly water ingress was from the grommets at the bottom of the gulley where the tailgate closed. New grommets and plenty of sealer solved the problem. Looking at the moon roof drain pipe n/s rear showed a 90degree bend in the down pipe before the 90degree bend through the bodywork to the outside world. I cut the pipe at the bend and inserted a plumbing 15mm copper pipe joiner which solved the bend problem. Two weeks later and plenty of rain, no more water in boot. Looking at refitting when time permits.

Herbie · June 20, 2020

7 hours ago, Barry14UK said:

"Our RX300 had a sun roof, as does our RX450h but we never open them, preferring instead to use the climate control.................."

The seal you see from on top of a sunroof (moonroof) does not completely prevent water/dirt getting into the cassette so it makes sense to slide the glass back every once in a while to clean and ensure drain holes are free. I have recently removed the cassette from an old BMW I was breaking for parts and due to having not been used for a long time the drive mechanism had seized and the glass could not be moved using the motor or by manually winding back with emergency tool provided for this purpose. There was also a lot of hardened and dirty grease/some corrosion that was making it difficult to move the components. (Some now favour a dry lubricant rather than grease but I tend to use what the manufacturer used). So don't assume that by not using a sunroof you will necessarily avoid any blockages and the next owner may want to open it and it may be seized through lack of use/attention.

I know what you're saying but I fear it may already be too late.

We've had the car about two and a half years and never opened the sunroof, so I'm more than just a bit apprehensive to try it now in case something bad happens.

As the saying goes 'If it ain't broke, don't fix it'.