Water Under Model 3?

[George75]

I got my 2020 Model 3 back in December. So far 7 months of limited (thanks virus) driving and since I'm here in Florida we're now getting more and more rain. My Model 3 spends all of it's time when I'm not driving it in the garage to keep the sun and rain off it. I've done some Googling and searching here but haven't found anything that quiet covers my question. If this question has already been answered please point me to the thread.

My question is:
After being out in heavy rain I'll notice the next day when I leave the house it sounds like I'm driving through gravel as I take off. The faster I go the louder the sound gets. After about 5 or 10 minutes the sound is gone. There's no major leakages of water in the garage from the car when parked after being out in the rain. No more than normal water flow off the body and onto the ground. There's no leaks inside the vehicle anywhere. I don't drive on dirt or gravel roads it's all suburban and urban driving. From what I've read I believe there's water trapped under the vehicle and I assume in newer models they must have created a drain to allow that water to flow out while driving?

Insights on water trapped under a 2020 Model 3 would be most welcome or if anyone has links/videos that would help me better understand what is happening. I assume this is normal and I don't want to put in a ticket and waste time on a potential non issue.

 

[lolder]

That sound is not normal.

 

[bbell]

Next time it happens try and press the brake petal while you are moving.

I find the brake rotors get rusty sitting after rain, and since I rarely ever use them due to regeneration they can "grind" for a bit until the rust is removed.

If you press the brake while moving at a good speed it will clear the rust away quick, and you will immediately hear a difference.

 

[brkaus]

I cannot imagine water sounding like gravel. I'm betting on rusted brakes as mentioned above.

 

[George75]

Thanks for the suggestions but I'm not using the brakes when I accelerate and the sound gets louder. The brakes work fine and make no sounds when I use them when it's dry out and no sounds when I use them when it's wet out. The car only makes that sound after I've been driving in the rain after it's sat for a while e.g. the next day. It's like all that water is pooling somewhere but not escaping until I start driving. If I drive faster it gets louder. If I drive for about 10 minutes the sound stops I assume all that water has escaped.

 

[Atari2600]

Hit the brakes to knock the rust off the rotors per bbell's suggestion.

 

[MikeHolliday]

Typical rusty rotors... As everyone else has stated... With the humidity in Florida, rust on Rotors is very common on all cars especially when they are not used often...

 

[George75]

I've never ever had rust on my brakes make that sound before. The car is garage kept, I work mostly from home. It only ever makes that sound after driving in heavy rain and only recently since we've only just stared to get heavy rain here in Florida. I do from time to time use the brakes to prevent rust buildup.

However to rule it out I'll take it out today because who doesn't want an excuse to drive somewhere I'll use the brakes just to rule out rust. The car is 7 months old and hasn't seen a summer yet and this is the first significant rains it's seen so I'm skeptical of rust this early in, I'd actually be concerned if these things are rusting this early on.

 

[brkaus]

Assuming it’s rust, what happens is the car is getting parked wet from the rain. Due to the regen braking the pads/rotors are cool so the moisture doesn’t evaporate quickly.

A car without regen has Warm/hot brakes from even the smallest amount of driving.

 

[LionXng]

Rusty rotors should be easy to see

 

[George75]

Well it isn't rust, I've driven it yesterday and today both times it was dry and not a sound from under the car. I have used the brakes on both occasions without any issues. I've also had the wheels rotated and there's no rust present. I washed the car today hoping if it is water getting trapped somewhere I could recreate it however that didn't work. I'll wait for the next storm to blow in and go for a drive in it then record a video and submit a work order. If water is getting trapped somewhere I want to know where or how and would like to give something to Tesla beyond it makes a sound in the rain.

 

[jmaddr]

Well it isn't rust, I've driven it yesterday and today both times it was dry and not a sound from under the car. I have used the brakes on both occasions without any issues.

This makes total sense with what everyone is saying. If it’s dry, there would be no rust, but if you come in from the rain, the rotors will he sopping wet. In an ICE car, this usually isn’t an issue as the rotors are hot from all the braking and the water evaporates. In our cars the rotors are typically cooler and the water does not evaporate...leading to more rust particles. The rust particles running round and round against the pads is the sound you are likely hearing. Eventually the pads wear away the rust particles and you are sound free.

Rust is not a bad thing, brake rotors are iron. The rust goes away the minute you have a few revolutions with the brakes applied.

I will say the Tesla is a little worse than most cars. I’m not sure it’s the pad material or something else, but my pads “freeze” to the rotor if I wash the car in the morning when everything is bone cold and then don’t drive it afterwards. Then when I take off a few days later they “pop” when I take off for the first time, and yes they make a grinding noise too.

 

[smartypnz]

Been having that on all 3 cars for 7 years. Our solution is - when backing out of the driveway - hit the brakes (somewhat forcefully) a couple of times. Guessing that it scrapes off the little rust that tends to appear. We are kinda humid here all year.

First year of Teslas - this was a common complaint - till someone figured it out - not using brakes to the extent we had become accustomed in an ICE vehicle.

So, I'm with the others cuz when I forget to do it, the car reminds me.

Let us know if this solves the problem.

 

[brkaus]

If your convinced it’s water, pull out on a concrete (or asphalt) surface. Go up/down any small incline. Turn the car around in the same area and go down/up the incline.

get out. Look for significant water spots.