FL5 Rear Undercarriage Floor collecting dirt. No place to drain?

[Sporky McGeuschky]

Hi y'all.

I was at Platinum Auto Films today checking out my car during a mid-wrap stage.

After taking some photos, I noticed a bunch of dirt and what can only be described as... sediment ... that seems to have collected inside the Rear Floor Cover Assembly(?) over my ownership period of only 6 months.

Dirt looks to have collected evenly on both sides of the undercarriage.

* Anyone here know if this has happened to your FL5?
What am I missing here?

* Total mileage currently as of June 14, 2025 at the wrap shop ~~ approximately 4,200 miles.

* The only mod I've added that I figure could possibly affect this is my RokBlokz Rally Mud Flaps. Not sure what adverse effect those might have on dirt passing into the inside of this assembly. The whole idea is that they block dirt from hitting the car. However, maybe as the dirt passes upward along the face of the rear Mud Flap, it goes up and over the flap, and into the Rear Floor Cover Assembly...?
* If this is due to the Rally Mud Flaps, then it will have only taken just over 3 & 1/2 months for this amount of sediment to accumulate.
Contrary to my daydreams that have me longing to see the FL5 as an AWD offroad rally car, as implied in my two original threads, my car has never been off road, and has only been on medium-kept Texas roads. I haven't even taken it on gravel.

* Should there be any sort of drain holes or vents in this floor panel?
Is this a design oversight from Honda?

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[Sporky McGeuschky]

I went online to the Dreamshop dreamshop.honda.com to look up the part(s) and this is what I found:

I think it is #9 in the diagram.

 

[Sporky McGeuschky]

Here is a look at the RokBlokz Rally Mud Flaps.

Rally Mud Flap install, March 2025.

While the front Mud Flaps are relatively narrow, the rears are very wide. I'm not sure how much wider the rear Mud Flaps may be than the rear wheel wells, if at all.

* Is it possible, that if the inside of the rear Mud Flap somehow reaches beyond the inside edge of the wheel well, then maybe dirt can be flung from the tire up and over the inside edge of the Mud Flap, beyond the inside of the wheel well, and into the Rear Floor Cover Assembly?
This would be saying that rather than preventing dirt from entering that space, the inside edge of the rear Mud Flap actually channels dirt into the space ... ???

Can this even be a thing?

The car is somewhat in a state of disassembly at the moment.
Difficult to assess at the current time.

I will have to look at everything up close after reassembly and get photos from underneath the car, once I can get it up on a lift.

 

[Sporky McGeuschky]

So, Do y'all think that a potentially "too wide" rear Mud Flap can be wide enough to introduce dirt into the FL5's Rear Floor Cover Assembly?

Or am I just set straight trippin'?

 

[AZCWTypeR]

Most newer cars collect some dirt due to all the plastic under trays. Not really a problem. Drilling a 1/4" hole on either side may allow it to exit while driving in the rain, though I would just leave it alone.

 

[J_D]

It's plastic. No risk of corrosion. I wouldn't do anything. Drilling a hole might just let more water splash into the area if anything.

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