Where do 3rd gens usually rust? My 92 is pretty clean so what are the problem areas?

 

On my 91 GTA the only place that seems to have rust is the lips of the wheel wells directly behind the rear tires. Other than that the undercarriage will usually have some rust...If you have T-tops like myself and the seals were bad at one time, water can get down in under the t-bars and when I first took them off and saw the rust I was horrified...come to find out it looked a lot worse than it was! Thank goodness

 

Floor pans, T-roof, anywhere theres steel..basically will rust.

 

Under the Spoiler in the back. Usually if it has loosened

 

I would say the driver side floor pan, the passenger side floor pan closer to the firewall (if your heater core leaks), spare tire well, inner wheel wells, rear bumper support.

 

T-top bar for sure. Mine was rusted to dust, only spot on the whole car though. Fortunately I didn't have any rot underneath the bar, so I just picked up a used one for $2 at a self-serve salvage yard.

 

check your cubby hole where your spare tire is.

Also on my 87 I found, (sense I repainted my whole car), besides the T top bar, that is a must to look at.

Open your rear hatch and take off your rear plastic. (say you were to change a tail light bulb)
Look at the metal that say your tail light would bolt to.
Now get a flash light, and see where the rear fender meets the rear panel.
Look for rust in this spot. I rust proofed everything. There is a rectangle hole that you have to get into. Maybe get a air gun and blow that out.
I also had 1 quarter size spot of rust under my rear ground effect when I took it off that I had to weld in a small patch.
I'm guessing that's what caused it.
My passenger side was spotless.

Good luck!

 

This is a pretty helpful thread! Never thought to check where the rear panel meets the quarter.

 

This could be interesting for you guys...
I just took the car to the bodyshop for painting. There's no rust on the car at all. Floor pans, T-tops, trunk well, everything spotless... but, there's one place with big spot of rust that went all the way through metal. It's on the bottom of the rear bumper support thing. You can see it on the pics. First pic shows where it is looking from outside and second one is a close-up. Fortunatelly because it's on this support it doesn't have any affect on the car, but what surprised me is why whole car is very clean and there's big spot in just one place...

 

my 92 has rust at the cowl drain, behind the passengers fender. the rubber door holds debris, and some above the drivers top door hinge. these may not be typical as I live in Hawaii, you also my find rust any where water can get without draining.

 

Do you have any pictures of the cowl drain? Mine is rusted on the driver's side cowl drain, behind the firewall...

 

Behind the frond wheel wells, where they meet the firewall. My 84 has rust on both sides, my 89 has no rust hole but I can see paint bubbling in this area.
My 89 is much more rusted than my 84 even though it's hard top : driver floor is bad, especially where it's welded to the rocker panel.
The bottom of the rear hatch is rusting as well. And as usual, the battery tray is gone, eating the front of the wheel well in the same time.

 

That's your bumper reinforcement. It's a bolt on part and not that expensive new. Good looking car BTW But I'd replace that bar.

 

Yeah my rear impact bar looks like that too. And is the cowl drain near the bottom door hinges where the fenders bolt to the body? I have rust in this location on both sides(opposite sides of kicker panels) and I'm trying to figure out where its coming from and how to prevent it from recurring

 

My 89 hardtop Iroc is rusting from the inside out on the roof on the driver's and passenger's side, in the process of trying to get a few patches from a donor car. This sucks

 

I've also been finding rust behind ALL the seam sealer......I just found some under the seam sealer in the cowl drain under the screen........scraping it all off, rustproofing, then resealing