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Discussion Starter · #1 ·
I bought a 2021 Model Y with a cracked octovalve. It was in an accident so not under warranty. I took the octovalve out and plasti-welded the crack. I put it back in the car but now there is air in the system (I think) and the two pumps keep running. I left it for 24 hours thinking it will bleed the air out by itself but all I got was pumps that might be broken (they were squeaking most likely because they were running dry). I tried unplugging the top hoses and pouring glycol into them directly, I tried turning the ac/heat on (the car does not produce any heat nor does the ac work).

It used to be that you turn the car off (disconnect the 12v battery and take out the emergency loop/disconnect) but with the Model Y it’s almost impossible to turn it off - the car is fully functional without the 12v battery and you need to cut the emergency loop, you can’t disconnect it). Anyhow, if you turn the off the car and turn it back on, it checks all the systems including the pumps and valves and in essence purges itself. At least that is theory on the older Teslas. But since I can’t turn off the car I have no idea how to purge the air from the cooling system. Any ideas?

I did try “resetting” the system - unplugging the 12v and the emergency loop - this will (supposedly) cycle the valves and purge the system, but this did not work.
 

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Tesla uses their toolbox to initiate a "bleed" program for this. Sorry that doesn't help much.
 

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Discussion Starter · #6 ·

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Actually I figured this part out. If you disconnect this plug the car acts the same way as if the emergency loop was cut - it powers down. After reconnecting the car does the initial cycle of checking the system but it did not fix the air in the system.
Try what I suggested above - starting the car charging makes the coolant pump activate (I guess the car wants to make sure it's working properly) but it will time out in a few seconds if the charging isn't generating much heat. But then if you open one of the front car doors and switch on the A/C system, the coolant pump reactivates to balance the system temperature - maybe so the coolant doesn't freeze?

If that doesn't work you can always try disconnecting the coolant pump from the car''s power, and running it manually from a separate 12v source, but that's very risky if you're not careful.
 

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Discussion Starter · #8 ·
It’s a good idea but that does not work. There are two pumps on the “octovalve” (I’m calling it octovalve but attached to the aluminum-plastic monster are multiple sensors, one octovalve, and two pumps). the two pumps are running constantly so that’s not a problem. The problem is that they are running dry. I ended up unplugging them so they don’t burn out. But over the last few days I go in the garage, plug them in (I can hear them turn on) try few things (like pouring the glycol into different coolant lines to prime the pumps or cycling the system to open the octovalves or turn on AC or turn on high heat…). But still air in the system. I’m sure the techs have a way to do it and it might be as someone pointed out with software “toolbox.” I’m hoping not so I can do it in my garage. But thanks for the advice.
 

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The traditional way to bleed any fluid system is to open up the highest point (whichever reservoir is highest) to allow the air to move that way, and then refill coolant as the air expulsion causes it to drop. I'm sure Tesla has a way to cycle the pumps in sequence to do that, but if you can't, this is the next best way.
 

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I bought a 2021 Model Y with a cracked octovalve. It was in an accident so not under warranty. I took the octovalve out and plasti-welded the crack. I put it back in the car but now there is air in the system (I think) and the two pumps keep running. I left it for 24 hours thinking it will bleed the air out by itself but all I got was pumps that might be broken (they were squeaking most likely because they were running dry). I tried unplugging the top hoses and pouring glycol into them directly, I tried turning the ac/heat on (the car does not produce any heat nor does the ac work).

It used to be that you turn the car off (disconnect the 12v battery and take out the emergency loop/disconnect) but with the Model Y it’s almost impossible to turn it off - the car is fully functional without the 12v battery and you need to cut the emergency loop, you can’t disconnect it). Anyhow, if you turn the off the car and turn it back on, it checks all the systems including the pumps and valves and in essence purges itself. At least that is theory on the older Teslas. But since I can’t turn off the car I have no idea how to purge the air from the cooling system. Any ideas?

I did try “resetting” the system - unplugging the 12v and the emergency loop - this will (supposedly) cycle the valves and purge the system, but this did not work.
I was able to charge my 2021 M3 coolant pumps by lightly pressurizing the reservoir thereby forcing Zerex G48 coolant into the system. The pumps quieted down almost immediately.
 
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