2024+ Land Cruiser & GX550 Musty Smell After Rain — Actual Cause Identified + Permanent Fix (Updated Toyota Part Numbers)

[Matthew@LC250Mods]

Hey everyone,

I’ve seen more and more owners mention a musty or mildew smell after rain or washing their 2024 LC250/GX550, and the usual fixes (HVAC cleaning, cabin filters, deodorizing, etc.) haven’t helped.

As someone who absolutely does not tolerate mold, I've spent a good amount of time digging into this and here's what I've found. A Lexus dealer also confirmed a key detail during a warranty repair.

I posted the full article on my site to help those who have encountered the issue.

Common Symptoms Owners Report​

• Musty or mildew smell after rain or washing
• Smell gets stronger when rolling windows down
• No visible water inside the cabin
• HVAC cleaning does nothing
• Windows stay wet for days
• Smell returns even after airing out

These symptoms point to the source being the doors, not the HVAC or carpets.

Common Misdiagnoses​

A lot of owners and dealers have assumed it was:

• Cabin air filter
• Evaporator mold
• A/C condensation
• Roof rack bolt leaks
• Carpet leaks

None of these match the pattern, and the issue always returns after cabin filter replacements, resealing roof rack bolts, and cleaning the evaporator coil.

The Actual Root Cause​

Toyota used an "outer belt molding" on early LC250/GX550 production with an internal material that absorbs moisture.

This molding:

• Takes on water
• Stays wet for days
• Releases a damp/musty odor into the door cavity
• Ventilates that odor into the cabin when windows move
• Continues smelling even though the interior is dry

This matches every owner symptom exactly.

A Lexus dealer also diagnosed this and replaced all four outer belt moldings with updated part numbers, specifically noting the original material as the problem.
Two things contribute:

1. Moisture-retaining outer belt molding material
2. Rubber drain plugs at the bottom of the doors that slow down or prevent proper drying

The doors themselves will get some water in them and this is completely normal on any car.
The issue here is that the combination of the moisture-absorbing outer seals + drains being plugged allows water to just sit and this is the perfect environment for mold and bacteria to thrive.

Old vs. Updated Toyota Belt Molding Part Numbers​

Location	Old Part #	New Part #
Front Left	68172-60110	75712-60100
Front Right	68171-60120	75711-60100
Rear Left	68174-60100	75722-60130
Rear Right	68173-60100	75721-60130

Our Recommendation for all 2024 LC250 owners​

1. Replace all four door "belt moldings" with the new part numbers.
2. Remove the drain plugs from the bottoms of each door.

The combination of updated moldings + improved drainage prevents the odor from returning.
This issue isn’t structural or terminal — it’s simply a materials issue on early belt moldings. Once replaced, doors behave like any other modern truck.

If anyone here receives different part numbers, dealer notes, or has additional findings, feel free to post them. I’m happy to update this guide so it stays as accurate as possible.