So I purchased my 2019 Express 3500 long wheel base passenger van (12 passenger) with 25,000 miles on it. L96 6L90E 3.42 G80 The van was a former rental unit from Enterprise. Bought it from my local Chevrolet dealer on their used lot. I grew up with the G vans in my childhood so vans are not new to me but the Express is as the very last van I drove was a 1995 GMC Rallye STX G30. I love my new Express and I am so impressed with how it drives, the power and most importantly its towing abilities and versatility. This is truly an all purpose vehicle.

What did disappoint me with this new Express compared to the G series GM vans I grew up with was how noisy they are going down the road. The seats rattle (when no one is sitting on them) and just squeaks and plastic rattle galore in my van. The truck was in such good shape I could not imagine the rental use being the cause of this although I admit I have never driven a brand new Express but from what I hear, rattles is just a way of life with these vans. I could not accept this, so.......

I removed all of the seats in my van, then tore off all of the interior panels and trim. I had my wife drive around while I located all the rattles. I had one rattle that was so loud it sounded like the driver's wall was going to fall off the thing. This is what I found.

The plastic heater duct that runs from the rear HVAC unit up to the front on the driver side wall to provide floor ventilation is held to the body with a total of 9 push clips with 3 being in the rear duct and 6 being in the front duct. My van only had 6 of the 9 clips installed. I was also missing one of two clips that attach the rear HVAC to ceiling vents duct. Furthermore, the clips that were installed did not do a sufficient job securing the duct tightly to the body so the whole duct was banging against the metal skeleton of the body inside the trim panels. If that was not enough when I removed the front driver trim panel behind the driver seat, I could see that two of the metal clips were not aligned with the holes in the body so they had bent and were scratching the interior sheet metal. This was causing my squeaks. I could not believe what I found on a one year old van. I saw zero evidence of collision repair or any work being done on the rear HVAC system. I could only surmise this was factory quality control problems. These vans are mostly sold to fleets so maybe they slap them together with a little less care than other assembly lines. I ordered all new clips for the HVAC ducts and verified the ones I had already in there were the correct ones but they still did not hold the duct tight to the wall to keep it from rattling. In addition to replacing the missing clips I also put 1 to 2 1/4 inch nylon washers on the clip before installing to take up that gap in addition I used double sided padded 3M tape on the body all all points where the ducts mounted to the wall with clips.

I put it all back together with care insuring the bent metal clips on the trim panel were installed correctly and lined up. While I was in there I ran wiring for a rear power inverter, rear work lights I mounted next to the receiver hitch, a rear LED dome light I could turn on from the back doors and 12 volt power outlets to the 2nd and 3rd rows.

Test drove and 90 percent of my rattles are gone!!!! The remaining are minor in comparison but seem to be coming from the trim around the rear door windows and some of the seat belt anchors on the rear outboard rows. What a huge difference that makes. If you have rattles coming from the driver side wall, check your HVAC floor duct and vents! I also found out the ceiling vent was misaligned blowing some of the air into no mans land in the headliner so I fixed that also. I now have just gotten a set of Bilstien shocks and very curious to see how much they improve the van next!

 

can you provide a little more detail on the 12 volt to the other rows? Where did you source the power from, and where did you run the line (under carpet, through door gaskets, etc).

 

Of course. I ran a 20 foot battery cable from the power junction at the fuse box under the driver seat through a 120 amp circuit breaker and ran the wire behind the wall trim panel to the rear HVAC unit where it terminated into a fused junction block. I then attached these to the trim panel before re-installing them. I just bolted them to the trim panel using 1/4 bolts and large washers.


I wired these plugs to that junction block I put in at the rear HVAC but I only used the big battery cable because I plan to add a high wattage power inverter later. If you only wanted the 12v plugs you could fuse them at 20 amps and wire directly to the same fuse junction under the driver seat. It was easy but if I did it again, I would have used this for a cleaner look and more practical since alot of devices only need usb so you can eliminate the adapters.



PM if you have any questions. I can take pics if it helps. Also removing the driver seat with the 4 bolts makes it much easier.

 

Yeah. GM absolutely doesn't give a crap about finish quality any more. At least they run well.