I'm feeling your pain. Austin MYLR delivered 8/21/22. I've been dealing with this water leak issue since I discovered it in October and despite 3 trips to Tesla service, three back glass replacements, a completely NEW liftgate (had to be painted to match), and a total of 7 weeks in the shop so far, my liftgate is still filling up with water and ultimately leaking inside the back seal.
After hundreds of hours studying this and reading this thread in full and many others, I believe I know what's happening and I will confirm it when I bring my car back to the SC next week.
What's happening
- It rains
- Water gets in through seams in the liftgate sheet metal hidden behind the "rear fog/reverse lights" (as referenced in the shop manual)
- The water is leaking INSIDE the metal liftgate itself where there is room for around 16 ounces to collect before filling up enough to spill out through the adjustable rubber bumpers. NOTE: These rubber bumpers are adjusted to the best height to make your trunk lid (ie., liftgate) appear level and square when closed. They are not "stoppers" screwed in to seal the trunk. Adjust them with caution or not at all.
- If the water collecting in the liftgate is not drained, it will continue to fill up and seep out through the adjustable rubber bumpers, trunk close button, or even through the plastic interior panels. In time, the water will rust out your liftgate from the inside, ruin the electric wiring and button, and cause the inside of your windows and glass roof to look hazy just a few days after being washed.
I cannot tell you how to fix the problem since mine is not yet fixed, but I can tell you how to greatly reduce the damage caused by the problem.
How to prevent further damage (short term)
- Open the liftgate part of the way - enough that the lowest point on the liftgate is extended as far away from the rest of the car as possible.
- Remove the two small, round rubber plugs located toward the outer ends of the bottom of the liftgate. These are soft rubber and approximately 5/8" in diameter. They are there to cover holes used during manufacturing that allowed excess rust prevention sealer to drain from the metal parts after they went through the priming process. They prevent road contaminant from entering the liftgate through the holes.
- Slowly raise and lower your liftgate by hand finding the optimal height to let all the water drain out without it getting inside your car.
- Put the plugs back into the holes until after the next rain storm, then repeat until the source of the problem is resolved. If you're driving in heavy rain, you may need to stop and drain your liftgate several times on your trip. If you wait for the water to fill up in there, it will start leaking into your trunk and may cause additional damage.
Here's what the drain plug looks like:
View attachment 897905
The drain hole will be revealed once the plug is removed:
View attachment 897902
Move the liftgate up and down slowly. Water will drain out at several different levels:
View attachment 897906
I hope this helps some of you.
RANT: It was really discouraging to read that others brought their cars to Tesla Norwell, MA as far back as October 2022 and were even told the issues was the seal behind the tail lights, and yet my Norwell Service Advisor never mentioned it and they could not fix my leak. I really felt like they were giving it the full effort to correct the situation. I'm not so sure any more... I still love my Model Y and believe it is the best car for me, but I am beginning to fear the service center folks think they work at a legacy automotive company and can ignore everything they have learned and is going on around them. My car was returned to be only partially assembled, with paint over-spray on my charge port cover, quarter panel, and trim, greasy hand stains on my headliner, and a badly mis-aligned (just replaced) liftgate after being in the shop from Nov. 21, 2022 - January 6, 2023. There was just no effort to quality check the outcome before asking me to pick it up - and now I discover it's still leaking after all this...