Check your rocker panel drains...

[destrux]

Only one side was clogged on my car... guess what clogged it? The stupid ass rubber flaps Toyota put on the back of those air vents in the door jamb dry rotted and fell off, and clogged the drain holes enough that it let mud/dirt finish clogging them. I got lucky and there's barely any rust, but I'd bet this is the cause for the rust in this spot in quite a few MKIII's.

This is with the door jamb vent out...

This is after I used a screwdriver, vacuum cleaner, and a hose to clean all the rubber pieces and mud/dirt out of there and get the rocker drains flowing again and flush the dirt out of there too. I would have taken a "before" pic, but I was pissed, and you can all imagine what dirt looks like anyway. It was filled up with mud to where that flat piece is though... it would have caused some major rust if I hadn't found it now.

I'm going to pull the trim piece on the outside and check for any rust perforation on the body and then dry this all out really well and coat it with POR-15. Hopefully that will curb any future problems.

 

[iruyle]

eeesh.
good idea to wash out the "gutters" under the hatch above the tail lights too. Took me a long while of parking outside to figure out that the debris washing into those tiny seams was enough to back rain water into my tail lights and tire well.

 

[te72]

Ugh... I wish these weren't so brittle over all these years. Definitely one part that would have been better made out of aluminum.

Discovered that on many cars (my buddy's FC, my 48 and the LS400), they have tubes that essentially carry the water dripping down into the car, to the bottom of the car. One tube on the Lexus was clogged (easy fix), and the nipple that the hose on the Chevy attached to was rotted away (no surprise there). Kinda surprised that the Mk3 doesn't have much in the way (that I've noticed from years of tearing apart the interiors) of effective drainage.