Rear Cooling Fans

I am confused as I thought only the 1.5's have two fans one basically drivers side integrated into the PEM and one bottom center for motor cooling. I do not see how you could see either from the wheels. Note you can catch a glimpse of the lower fan in front of the rear wheel at least on my 1.5.

But I thought the 2.x have one fan in the bottom. Again not really visible from behind the rear wheels.

I'm not sure where they are located, but my 2.0 Roadster single fan assembly failed and Tesla recommended I upgrade to the dual fan assembly. My car gets extremely loud on semi-hot days in California, i'm sure it would be even louder/more frequent in Texas heat.

tonybelding said:

For a few days I've noticed the sounds coming from the rear fans have gotten louder. . . annoyingly loud, at times.

This evening after a short drive, I parked my car in the garage and plugged it in -- and soon the loud noise began. I took a flashlight and peered behind the left rear wheel, and saw the fan there running. Then I peered behind the right rear wheel and saw the fan there NOT running. Hmm. Shouldn't they both be going at the same time? Is the one making a lot of noise because it's running at maximum and trying to do the job of both?

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I have a 1.5 but I can contest that the 2.x's are louder when they charge and when they cool down, all due to the fans/blowers going on. I had a 2.0 for a week and that thing was crazy loud all the time charging. My 1.5 when charging is fairly quiet, granted you don't count the HVAC fans kicking on to cool down the ESS every now and then.

Below is a pic of a dual blower setup from the 2.x. I don't have a 2.x nor have I personally seen the routing, but my guess is that the drivers side blower is dedicated tot he PEM and the passenger side is for the motor. I presume that the PEM blower was running due to charging / being driven where as the motor didn't reach temps high enough to kick on, and it doesn't need to be cooled down while charging like the PEM in most cases.


Here's some details from Doug_G about the details on the blower. I believe the pic below, at least the first one is of the updated blower. The Y-Cable he's talking about appears to be the upgraded part where the one motor powers both fans. The older blower must of had two motors and two fans from what I can take from it:

PEM, motor gets too hot -- fans failed - Page 20

"Originally Posted by Doug_G Both of the original fan cables are connected into a single Y cable. There are diodes in the lines, so if the car powers up either the PEM fan wire or the motor fan wire, the single motor gets the power and spins."

tonybelding said:

As for the loud noise... I just don't know. It seems much more noticeable in the last few days, but maybe it is normal. I think I'll just keep the VDS on the temperature display for a while and see what comes up.

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If there is vibration with the loud noise, then it is likely that there are leaves or other debris inside the fan squirrel cages causing an imbalance to the spinning fans. Cleaning whatever got in there can do wonders for quieting things down.

JohnGarziglia said:

If there is vibration with the loud noise, then it is likely that there are leaves or other debris inside the fan squirrel cages causing an imbalance to the spinning fans. Cleaning whatever got in there can do wonders for quieting things down.

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Good chance this is the cause. Check this first.

tonybelding said:

OK, I'll look at that.

BTW, I have a friend who is an electrician and spends a lot of his time repairing electric motors. His advice: "Don't worry about the noise. Soon it'll seize up and become quiet again!"

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Hate to say it but he's right. Every time my fans failed they started making a lot of noise first. But I've also heard them get noisy when they're working really hard because the PEM is clogged.

When the fans are not turning, reach in and see how easy it is to spin them without power. They should spin fairly easily. If they don't, you might have a bad bearing.

tonybelding said:

I'm beginning to suspect this. I can't really see anything wrong with the fan, but the PEM often is quite warm. When I'm driving, the PEM's thermal display spends a lot of time in the uppermost blue bar, one notch below yellow.

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Mine is pretty much there all the time too. Driving downhill in the morning, it will stay one notch below that, but most of the time it's right below the yellow. This is after a complete cleaning, and even PEM replacement, blower gasketing, etc., so I'm thinking it's "normal" for summer. I've not gotten any more 11xx warnings since we did the gasketing, and it's never actually moved into the yellow zone that I know of (even with the 1144 / 1146 warnings).