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Oily Fluid Leaking From Autopilot Camera Housing

On the morning of May 8th, I went into my garage to clean the Model S windshield before my wife left for work and noticed a ~6" long drip/run of a clear oily fluid running down the inside of the windshield from the Autopilot camera housing. The fluid felt somewhat similar to a machine oil... certainly a strange thing to be coming out of the camera housing.


I had already been trying for about 4 weeks to set up a service appointment to address some other issues when this occurred and, since I was getting nothing but silence from the service center, I decided to e-mail corporate. This resulted in me receiving a request to set up an appointment from the service center about a week later.

Anyway, I picked up my car from the service center yesterday and was told that the techs confirmed the leak since there was still some of the stuff in the camera housing or whatever and that they resolved the issue by replacing the rain sensor. Included in the service paperwork was a note to advise the customer that the 'sensor may drip again due to heat if the vehicle is parked in an extremely hot area.' Unsurprisingly, the service adviser wasn't really able to adequately explain what had happened or the potential implications. Everyone I had spoken to about the issue was pretty confused/surprised when I dropped the car off, stating that they had never heard of something like this happening.

To anyone who has pulled one of these housings apart, was the leaking fluid the result of some sort of rain sensor adhesive breaking down? I mean, the sensor is optical so I wouldn't think that it would be filled with fluid or anything and, while Autopilot seemed to function properly after the leak, I didn't think to test the rain sensing wipers (it's not like it rained here)... so I have no idea if the function of the rain sensor was impacted. I also wonder what the temperature tolerance of the substance is, since the car was just sitting in the garage all weekend and we didn't experience highs in excess of 70°F. It did hit 97°F while the car was parked outside about 4 days before the drip occurred/was noticed, but that's not particularly hot for the Antelope Valley (the car was parked outside in 114°F heat in the past and everything was fine). I'm also left wondering if the fluid could stain any of the interior bits should it drip down onto them during a potential future recurrence.

Has anyone else run into this issue?
  • Informative
Reactions: gowthamn and croman
Good question, I too came across a small drip run from the same vicinity of the front windshield just beneath the forward facing MobilEye Camera. I have checked it once since that initial incident (about two months ago) and only found a minor dampening of the window one other time when it is hotter in the vehicle (e.g. 104 degrees F.) Could be related to rain sensors, though it could be keeping the camera eye 'clean' like blinking your eyes does, but I agree it should never 'leak'. In the meantime I am monitoring and keep a paper cloth towel handy should it reappear.


Well-Known Member
Nov 25, 2012
Visalia, CA
'sensor may drip again due to heat if the vehicle is parked in an extremely hot area.'

I thought rain sensor uses infrared light for its optical sensor.

How Windshield Wipers Work

Tesla may be using some other kind of rain sensor that requires built-in fluid that is susceptible to leak due to hot weather.

In that case, how does it withstand the heat in United Arab Emirates after its grand opening just this year.
I thought rain sensor uses infrared light for its optical sensor.
They do--basically an optical system measuring the change in refractive index of the medium outside the windshield.

That said, a little research indicates that many of these sensors use what looks to be some sort of gel adhesive to stick to the windshield and it's possible that the dripping is the adhesive gel breaking down... but the materials data I've found indicates that some of this stuff should be good up to 356°F. I'm kinda hoping that someone like @wk057 who has taken this stuff apart before will chime in with some insight.
  • Informative
Reactions: EVie'sDad
I just got my car back. They said it was gel from the rain sensor. It's unclear if this was the adhesive holding the device to the windshield or if it's part of the sensor itself. They replaced something (either the housing or the entire sensor, I'm unsure). The line item from the invoice is attached here:
rain sensor repair line item.PNG
Just another data point: I have this exact problem on my 2016 Model S (AP1, built right after front fascia refresh). I'm wondering if I should just wipe up the oil and soldier on, or if I should have the rain sensor replaced. The AP camera and rain sensor are both working okay.

If everything is working, it's probably not worth the time/hassle of bringing in the car. If you have to bring it in anyway (multiple things to get fixed/serviced), might as well tell them to do the rain sensor, also.

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