Curbside Tech / COAL: Deconstruction – More 2020 Tesla Model Y Under The Skin

Tesla Model Y

While I’m overdue for an update on our 2020 Tesla Model Y, it’s currently at 5,558 miles without any significant issues and has settled in to the garage as “just another car”, not being treated or looked at much differently than any of the others.  Which is a good thing, I’ll hasten to add, it just gets us around well.  The regular non-winter tires are back on it and I do have a roadtrip to Minnesota planned with it next month.  I intend to report back after that as it will entail multiple Supercharger stops for the 1000+mile journey each way, much of it across the Middle Of Nowhere, USA.  Along with four days near Minneapolis it should enable me to generate some good range data.

However, and more to the point of this particular post, for the last month a rattle inside the car has been driving my wife nuts.  Oh no, Lordstown 2.0, drunken disgruntled assembly workers, union agitator sabotage, what could it be?  It sounded like something rolling around on the floor and she dispatched me, Mr. Fancy Big Red Tool Chest Man, to figure it out.  I therefore went out to the car, opened the rear door and found an Advil pill on the rear winter floor mat, clearly it had been rolling around there.  Triumphantly I returned to the house, the great problem solver.  Until the next day, when I was informed of my failure; the noise was still present and still annoying.  I then drove the car, was able to replicate the noise, and sort of isolated it to the right side of the car.  We loaded our son into the back seat, then the cargo area and tried to localize it more, and I myself rode laying on the rear floor with my wife accelerating, braking and turning hard until I almost barfed to realize it was actually under the floor.

Tesla Model Y

Before that though I thought perhaps it was under the rear seat so I pulled that cushion up (no bolts, just spring clip pressure holding it in).  Nothing seemed amiss under here and the wiring you see is for the three rear seat heat positions – this is a rarity, most rear seats that have heat only have it for the outboard positions.

One of the negatives in a Tesla (at least the Y and 3) is that engaging the rear seat heat requires someone in the front to enable it via the touch screen or verbally.  I find this as(s)inine, I would (due to false modesty perhaps?) never ask the driver to turn the heat on or off under my ass.  At least it has it, I suppose, but a set of buttons for the rear occupants makes sense here.  While I like the car and think it does many things extremely well, I have no problem criticizing aspects of it I find annoying or poorly designed, such as this.  My kids love heated seats, always use them when my test cars are equipped with such, but never ask for them to be engaged here.  Yeah…

Tesla Model Y

Asking about my noise/rattle issue in the Tesla Forums revealed that there are floor ducts for ventilation (in addition to the ones in the rear center console, interestingly they apparently only flow cold AC air if a rear seatbelt is fastened, that’s how it knows someone is back there that may need air).   In any case, they are ducts as in some other cars with a large opening but in this case no cover whatsoever on them.  So stuff can on occasion roll in there, especially under hard braking.

From the underseat opening, these ducts angle down into the floor and then sort of curve under the center console where they are attached to a central duct coming from under the dashboard.  It appeared that something may have entered the duct and was now rolling around and trapped in there.

Tesla Model Y

The forums suggested backing up at high speed and slamming on the brakes as well as using an unfurled wire coat hanger with a sticky gob of duct tape to either dislodge or catch the offending item, I tried both, neither worked.  The next option was to start disassembly of the interior to get to the duct (since I was loathe to take it to the Tesla service center and have them do it and potentially and rightfully charge me if it wasn’t a Tesla bolt or screw or something that was found).

Tesla Model Y

So the first step was to use a T45 bit on a ratchet and unbolt the seat.  Four bolts and five minutes later the seat was undone and resting tilted back onto the back seat, the wiring is all in one wire bundle with a lot of slack so no issues there.  The next step was to get under the carpet, removing the seat frees the overlapping velcro-taped joint between the front and back sections, now the sides are what’s holding it in.

The door sill panel unclips with light pressure up until where it goes under the dash, that clip didn’t want to move but the piece was flexible enough to move around.  The carpeted side panel of the console is held on with almost a dozen clips and just basically pulls off with light and careful pressure as seen above with it removed.

Two small clips whose heads pull out slightly to release them unfastens the carpet at the front of the door hinge area and under the center console panel, however the lower main section of carpet is glued to some large styrofoam pieces that are underneath it and form the flat floor above the metal skin that separates the passenger compartment from the battery below that floor.

The styrofoam sort of holds everything including the ductwork in place and presumably provides both a flat floor surface as well as noise and temperature insulation, the chunk pictured above is from the firewall area, the oval cutout area at the bottom is the joint to the floor area (it’s several pieces), the carpet is folded back here and out of frame.

The carpet easily untucked from behind the glovebox but remained fast under one section of the center console which others have recommended removing but I was loathe to do today, instead just lifting it and working my hands under it.

Working the carpet and the styrofoam revealed that the styrofoam was actually several pieces that sort of jigsaw puzzled together and eventually it sort of folded up and out of the way for me and I was able to get the duct out.  Note how it has an elevation change, if something gets in there and drops down it is unlikely to extricate itself.

That duct section just pressfits into the section that feeds it from under the center console, made out of thin black plastic it is almost exactly how the dashboard ducts were in my Porsche when I took that apart to replace the ignition switch some years back, just separate sections that slip into each other.  Apparently this part of the duct is in fact different (larger) here than in the closely related Model 3, so either it’s a running change that the newer M3s have as well or there was a realization that the rear volume is larger in the Y, so more air would be welcome.

I was dismayed though to realize that there was nothing in the duct save for a small piece of lint, it’s possible it fell out during disassembly or it got under there some other way.  So with everything sort of akimbo and the passenger seat resting on the backseat I drove around the neighborhood and again heard the offending item rolling around, more clearly than ever in the passenger footwell.  After heading back home I crouched on the driveway and ran my hands around the metal floor, under and around every wire bundle, but to no avail.

Tesla Model Y

So I got back in the car again, and when I turned I heard the item rolling towards the door again.  I pulled over immediately and from the passenger side once again ran my hands around and under everything and within a few seconds felt and grasped the offender!  It turned out to be a somewhat stale looking yellow jellybean candy.

Heading back home in real triumph this time I displayed my bounty to the family, none of which fessed up to being the offender.  But I have my (usual) suspects, I don’t think it’s been there from the assembly line.  It only took about ten minutes to reassemble the carpet, clips, panels, and remount the seat and tighten the bolts.

Note that the T45 socket and ratchet were the only tools needed beyond a small pick to unclip the clips and maybe a panel tool would have helped to undo the other clips too, although my fingers worked just fine as well.  The days of millions of screws for trim are long gone in modern assembly.  It’s easy to see how they can put these together so fast.  No rattles so far (that weren’t self-induced) after seven months.

Tesla Model Y

After reading more about the situation I ended up ordering a set of grilles from Etsy, it appears that someone 3D prints these and sells sets for about $12, they just clip or tape on to the ducts and solve the issue according to the reviews on the forums, a couple of vendors on Amazon sell similar items apparently.  I’m still not completely convinced that the jellybean was actually inside the duct or if it just entered under the carpet just to the side of it (it doesn’t fit all that snugly to the carpet), but it ended up under the passenger floor area.

The way these ducts are shaped to conform to the underfloor area (i.e by angling down right after the opening) makes them hugely susceptible to having small items enter them, some sort of grille should have been standard from Tesla to prevent this.  My grilles should arrive next week, until then I’ve asked everyone to refrain from eating anything in the car.

Tesla Model Y


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