Hasn't rained since I got ownership of the 02 but today there was a musty smell when I opened the door. The passenger side carpet front and back is wet.
The A/C seems to be draining OK and never had the problem before this hard rain.

 

Have you run your car through a carwash? Or, washed it in the driveway.... anything that might have caused a lot of water to drain into the HVAC air inlets in the cowling under the windshield?

I'm not familiar with exactly how the RL drains away that water, but a lot of cars (including C5 Corvettes) have rubber drain tubes, like little udders, that can get clogged with leaf particles and dirt, allowing water to back up and overflow to the interior. These are usually accessable through the engine compartment, but are often hard to reach. The usual technique with udders is to "milk" them by massaging to allow the junk to discharge. Again, not sure if Acura RLs use this system..

The other thought is the windshield seal. If the windshield has been replaced, the seal could have been fitted incorrectly, or the sealant might have failed.

 

It's the original Honda windshield but today I had the sunroof drains blown out with compressed air. Hoping for the best.

 

I've never had that done.... please post if it solves your problem.

 

I had the exact problem long ago and it's all dry and clean now lol. After a rain, the front passenger carpet is wet. I fixed it by placing the electrical tape (black color) where the front plastic and the front windshield meet on the bottom. I don't know, this method work for me, not sure about your situation. Hope thats help.

 

mine does leak sometimes too.its only when I park the car up the hill.
But it doesnt do it anymore its so weird.

 

I had the same issue and resolved it last week. There is a piece of foam that is worn out under the wiper motor cover (not sure what you call it).
1. Open the hood
2. Remove both wiper arms where they bolt on
3. Remove the plastic hold downs from the plastic wiper motor cover, there are approximately 4-5 larger ones and approximately 7-8 small ones
4. Now lift the cover up a little and you will see an oval hole that goes directly into the ventilation system, you should also see part of the cabin filter.
The foam on the bottom of the cover that you just moved is worn out and letting water run inside.
5. I just glued a piece of foam on the metal (car body) where the worn foam met the metal and put everything back together.

While you have everything apart you can run some water down the windshield and will see that it runs toward the hole.
We had a lot of rain this week and all seems good, I put the floor mat back in today.

Sorry no pics, I thought I would be the only one with this issue.

Good luck
John

 

Having the sunroof drains blown out with compressed air has seemed to fix the leak

 

Can anyone post some pictures of the work you've done?
My car does it too..I've notice some water this morning .Not much though.
I only notice it when I park up hill like the other guy said.
Thanks