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Truck leak / Gas door area bubbling and rusting through?
Posted: Fri May 21, 2010 1:24 pm
by edawg.motorsports
I have a fairly bad truck leak as well as interior leaks, read drain tubes posts and will get to those for interior, but haven't checked in to the truck leak. My concern for the trunk leak (and it may not be related) is the fact that the paint under the gas door is bubbling and starting to rust at an extremely rapid rate now, same side as the truck leaks on. Any thoughts?
Thanks
Re: Truck leak / Gas door area bubbling and rusting through?
Posted: Fri May 21, 2010 2:13 pm
by CMNTMXR57
Any leaks through the gas fill area should work it's way down into the wheel well (over the plastic trim pieces) and onto the ground. It *shouldn't* leak into the trunk. Shouldn't being famous last words!

Re: Truck leak / Gas door area bubbling and rusting through?
Posted: Fri May 21, 2010 4:09 pm
by dpcookson
Pull the side carpet pieces away from the wheel wells inside the trunk and have a good look at the metal, you may find some rusty holes there.
Re: Truck leak / Gas door area bubbling and rusting through?
Posted: Fri May 21, 2010 11:54 pm
by Archon
Check the bolts around the spoiler, and the seal around the center brake light. Those are some common leak areas. Some have had some problems with the weather stripping for the trunk. Sometimes the body seams are not fully sealed, too.
The rust under the gas door is a fairly commong occurrence for the 2000+s. Unfortunately, it is not surface rust, but is rusting from the inside out. There is foam between the body panels in the area, which holds moisture and rusts the area. You're not likely to see anything from inside the trunk. The fix is to have the body panel cut out, the foam removed, and new metal welded in. The estimate that I got for a repair was in the area of $800.
Re: Truck leak / Gas door area bubbling and rusting through?
Posted: Sat May 22, 2010 8:53 am
by skid05bonnie
I had a trunk leak on my bonneville that turned out to be the rear strut mount body seam(where the rear upper strut mount is welded to the body). I resealed it with under coating and that fixed it. As far as the gas door my 2000 grand prix had the same problem. In that case it was the fuel cap hanger was missing so when I filled up the fuel cap was resting on that area and over the years it started to rust. My Bonneville is missing the hanger also but I'm very careful now about not resting the fuel cap on the body while I'm filling up
Re: Truck leak / Gas door area bubbling and rusting through?
Posted: Mon May 24, 2010 10:34 am
by CMNTMXR57
Archon wrote:Check the bolts around the spoiler, and the seal around the center brake light. Those are some common leak areas. Some have had some problems with the weather stripping for the trunk. Sometimes the body seams are not fully sealed, too.
The rust under the gas door is a fairly commong occurrence for the 2000+s. Unfortunately, it is not surface rust, but is rusting from the inside out. There is foam between the body panels in the area, which holds moisture and rusts the area. You're not likely to see anything from inside the trunk. The fix is to have the body panel cut out, the foam removed, and new metal welded in. The estimate that I got for a repair was in the area of $800.
To add, it's an issue on most GM FWD vehicles for the late 90's+, particularly our cars as well as Grand Prix's, Monte's, Lumina/Impala's, etc...
It cost about that to fix it on my GTP and I can see my Bonneville (along with hood herpes), having the same issue.