95-99 wheelhouse rust thru

[Guest David G]

I've heard that many of the mid-late 90's Rivs, and some other Buicks of those years, have suffered from the right rear wheelhouse rusting thru at the top of the WH. This has happened with my 98 Riviera, an area about 2"x6" at the very top, not too far away from the shock mount...

The problem was not evident about a year ago when I personally replaced the rear air shocks. I was baffled at how quickly it seemed to have progressed. Total rust thru. Looked like the undercoating suffered a failure, cracking apart and allowing moisture and dirt to accumulate behind it. Also discovered several pinholes trailing down the back side of the WH. I contemplated replacing the wheelhouse pieces, parts cost of about $95, but the body shop said that labor for that option would be cost prohibitive. So I had them clean up all traces of rust, they then formed a steel patch panel to place at the top of the WH, affixed with body panel adhesive. Then applied fresh undercoating. Doesn't look bad, for under $300.

The rest of the car is pretty clean, rust-wise. NO SIGN of this problem in the left wheel house. So how many of you have had similar issues with this WH rusting out? Seems very odd, don't know why the Rt side would be a problem. My body shop says they actually have NOT seen this, but I've heard otherwise from other Riv owners.