So, I finally had a little time to investigate the widespread reported-issue of the doors retaining water. Hopefully this puts a few people at-rest for their concerns, and dispels many of the incorrect beliefs…
A quick summary:
One other comment; I have seen an image or two of people actually having water retained within their door panels – and encroaching into the interior trim pieces. THE “ISSUE” ABOVE IS NOT YOUR ISSUE. You have a different problem, one that is real and should be checked via your dealer-warranty.
Hopes this helps calm some of the panic (term used lightheartedly) floating around about the doors and needing a recall, etc….
A quick summary:
- EVERY Trailblazer has this condition. Its only “evident” however if you’re parked on a flat surface. Any incline or angle, and the majority of the water will already drain before you open any of your doors. Similarly, depending upon the orientation of the vehicle on the inclined surface, only certain doors might exhibit the issue.
- The water is NOT being trapped within the inner and outer door panels. I have verified this.
- There is zero risk to any electrical or speakers within the door itself.
- The drain holes in the door panels are sized correctly, and there is nothing blocking their functionality within the doors. There is no need to make these holes larger.
- The drain holes in the door panels do NOT get blocked by the exterior plastic cladding, nor by the door-sill or weatherstripping when the doors are in their closed-position. I have verified this; I observed & located the holes and the sufficient gaps to all these other potential surfaces.
- The water is being trapped in a shallow “V” section at the bottom of the exterior plastic cladding, between the outer door-panel and the plastic cladding. Have a look at my attached images; I have verified this.
- With the vehicle parked on a “flat” surface, the water will be retained in this long channel. When you open the door, the bracket-angle of the door anchored to the body opens the doors on a slightly ‘upward’ angle (just a few degrees), which makes all of the water in this channel travel to the front-corner of each door, overflowing and spilling out at the front-corner between the door and the cladding. It APPEARS to be coming from the front drain-hole in the door, but it is NOT.
- It is inherent in the design itself, there is no defective or misinstalled part, and there will not be any ‘fix’ from GM ever issued. (At best I could see a TSB issued to alert dealers what it is / what to do if a customer ever complains.)
- As an experienced engineer, I personally consider it a non-issue and will not be performing any modifications to the underside of the plastic cladding. And I live in Michigan, where we face 3-4 months of snow each year. (As a testament to my vehicle ownership, we still own our 2002 Trailblazer, 250k+ miles and still going strong; it has lived exclusively outside for the past 15 years. I know and have seen firsthand where high-potentials of rust can and will be formed…)
- HOWEVER, if you want to still guarantee that no residual water stays in this shallow channel, you can perform the following at YOUR OWN RISK:
- Drill as many 4-5mm sized holes along the length of the BOTTOM of the body cladding as you desire. IMO, three should be sufficient – one at the front, middle and back of each cladding piece.
- Periodically clean these holes with any poking tool to free it of any dirt or debris buildup.
One other comment; I have seen an image or two of people actually having water retained within their door panels – and encroaching into the interior trim pieces. THE “ISSUE” ABOVE IS NOT YOUR ISSUE. You have a different problem, one that is real and should be checked via your dealer-warranty.
Hopes this helps calm some of the panic (term used lightheartedly) floating around about the doors and needing a recall, etc….




