No moon/sun roof here. The hole wasn't there about a year ago, when I replaced the rear air shocks personally. I suppose it could have JUST been starting. It's resulted in wet spots showing thru the trunk carpet a few times in the past several months, which I attributed to possibly being from the power antenna I replaced, so I rechecked my installation and hadn't noticed a leak since then.

The show owner says he's never seen a hole like this on a Riviera. It looks to me like the undercoating split and peeled back, allowing moisture/dirt to accumulate behind it, resulting in the rust out. The left side shows no sign of problems. The right side wheelhouse has a seam along this rust area, I wonder if the left side has a seam there also.

I'd have taken on a repair attempt myself, but free time is in short supply, and it's my year round daily driver. Getting this patched properly might help the car survive long enough for my 11yr old daughter to get it as her first car. YES, she wants it.

Mine's about that size, but looks like it will be larger once all the rusty metal is cut out. It's not right by the shock mount, but close enough to worry me.

Dave, can you possibly get pic's of the area before repair. I thought i noticed some surface rust in right rear fender well when I was doing the brakes. Had every intention of going back in and sanding or spot sand blasting the area and coating it with the product that Albert recommended, I think it is POR-15.
Or something close to that. I have printed out what I want to buy for a starter kit and try it.
I'm hoping I haven't waited too long to revisit this fender well, it was last fall when i noticed it and forgot about it until you brought up your problem.
Good luck with your repair.

Sorry Rick, too late for pics. It's simply the top middle area of the wheel well. Mine is already a large hole about 2" across, maybe 5-6 long, running front to back. It's in the shop bright and early in the morning. I'm afraid they're going to need to remove more material than they realize. There's a fairly large rusty surface surrounding the hole, and that steel is NOT very thick.

Dave if its's too late for before pics do you think you can post some of the repair for us? I'm in the rust belt and if this is a problem for our cars it sure would be nice to get at it sooner than later...sorry about yours though

Actually, I think I DID take a couple pics a month or so ago. Will have to dig around the camera and HD and see if I can find them. I'll try to take some "after" shots also.

Huh, couldn't find any "before" pictures, sorry.

Picked the car up again today. It looks nice on the underside, although they could have resprayed the WHOLE wheel well, it would have looked a hell of a lot better. Inside the trunk, I'm not so sure. I pulled back the carpet, and on top of the wheel well patch, they had sprayed what looks like spray-on expanding foam sealant. And it's thick. Like a couple inches thick. So I have no idea what it looks like underneath. I'll be calling the shop tomorrow to ask what exactly they did on the top side. Odds are I'll be pulling that crap out and finishing it off with something else. Pics later, tomorrow.

Ok, here's the skinny on the foam sealant inside the trunk.

The metal patch plate is fitted to the underside of the wheel well hole, "adhesived" in place, and undercoated nicely. Really no complaints from the outside perspective. However, since the metal patch plate isn't a perfect fit against the hole in the oem surface, there are gaps on the TOP side of the plate inside the trunk. The expanding foam sealant was applied to the top to seal out air/moisture from the inside and keep the patched area clean and unexposed. Yes, they probably sprayed more than needed, and I can see where they did in fact already cut it back some. I plan to cut it back a bit more, then find some kind of light gray sealant to cover the yellow foam, so it's not quite so conspicuous. It's actually not even visible once the carpet pieces are back in place, but I just don't care for how it looks. It's actually partially surrounded the large wire harness that runs across the top of the wheel well.

Ok, off to snap a couple pics.....

BTW, after cleaning up the rust and removing old undercoating, they found several additional rust pinholes going down the back of the wheel well. These were cleaned up and sealed, at no additional charge to me. All in all, I certainly feel I got more than my money's worth for $232.

To bad you didn't live closer or I'd be bringing my car in for a quick fender well repair job for short money.

Rick, if I didn't have rust thru yet, like you, I'd have sanded it down and POR'd it myself. I wasn't up for dealing with a big hole though... Have you rechecked the condition of yours yet?

Also PM'd on the cone filter earlier.

Hi im new to the riv schene and im about to buy a 96. I for the most part know GM stuff good so I have more questions about other things to look for.

Any typical rust area's on the undercarriage to look for , etc?

depends where it has ben driven but you could check the brake lines under the car, specialy the rear ones what seem to get rusty.
other then that i dont relly know. mine is 96 tho and so much as i know its been there where i live ower 4-5 years and driven on winter. on winters whe salt the roads to avoid ice.
so its easy for the rust to start eatign the car. but so much has i have looked under the car it seems to be fine. only some survice small rust you can notice.

ohh and one place is the trunk. some rivs have water leaks and the water gets into the trunk under the spear tire where it can start to rust.