Hello again, after recently solving my fuel economy and power problems on my 1994 LS400 I recently noticed the carpet on the passenger side was soaked and have now confirmed that water is definitely getting in via the sunroof, I have cleaned out the drains the tracks and all areas around the sunroof and have confirmed that the drains are draining...and draining well. Water tests show the water running out quickly and freely. It appears that the water (once past the glass) is dripping in through rivets but in theory water shouldn't get there in the first place so I'm suspicious that the actual seal around the glass is the culprit. If anyone has solved this problem please let me know... I'm considering running a bead of "flex seal" like product or liquid electrical tape around the joint. But before I do I thought I'd listen to this community for advice.

 

How is the condition of the front windshield seal? Has the front windshield ever been replaced?

If the sunroof is draining fine, check the windshield to see if water leaks into the cabin. Try to spray water with a hose at the top of the windshield, and away from the sunroof to see if it still gets in.

Also check all of your door seals.

 

Temporarily tape the sunroof glass to body seam to see if water is getting in somewhere else. The sunroof rubber is not designed to seal 100% that's why there are drains in each corner. It is possible water is leaking between the roof frame pipes/outlet and the vinyl hose I've seen this happen.

 

Are all 4 drains working fine? In my case, 2 rear drains were not working well enough. Cleaning those rear 2 fixed the problem. But compared with front 2, rears were not easy to clean since they were located way behind the roof and could not see nor to access easily. I finally used a bore scope camera to find and identify them.