Prius Thermostat Replacement

2nd gen prius thermostat replacement - overall not too terrible of a job

[@iankennedy8457]

I don't know if anyone has told you yet, but the coolant circuit for the ICE radiator and the coolant circuit for the inverter are two SEPARATE circuits that do not communicate. they need to be drained and serviced separately and thats why they have two overflow reservoirs in the engine bay. Good luck!

[@CtrlAltDefeatTV]

Thanks! You're absolutely right on that point there, I read up on that a bit after making this vid

[@bat__bat]

Yea, I've had to change two inverter coolant pumps on two prii, but no ice water pumps yet. On the first one I drained the inverter coolant, removed driver side headlight (3 screws), and the electric pump is right there behind the headlight. Takes 5 min to swap out at that stage. Then put headlight back, open air bleeder screw, add coolant in that overflow bottle. There's no thermostat on that coolant circuit, it just circulates full time like an aquarium pump. On the second Prius I saved some time doing the same thing only slightly differently... This time, no draining the coolant. Remove the driver headlight. Use two clamping pliers (sometimes referred to incorrectly as channel locks), one clamped on either side of the hoses exiting the old electric pump. Now swap pumps. Remove clamping pliers. Put headlight back. Open bleeder valve just very briefly. C'est fini. Oh, and I remember the car giving a peculiar code for overheating that inverter coolant circuit. Using torque app like in this vid, you can check the mg1 & mg2 inverter coolant temps. Once one of them hits 175-185 F, that ❗ triangle alerts and throws the code. One of the cars would operate, but after a few minutes on the rd it would overheat and the car would set to limp after just a couple minutes. Sit, cool, drive again maybe 5-10 mins before limp again. On the second car, the electric pump had burned up or shorted internally, so it blew a fuse every time the vehicle powered on. And the vehicle senses that fuse blown and will not "Ready" the car. That one took me a few hrs to figure out because the car throws no code. Once I discovered the blown fuse powered that silly pump I'd become familiar with I knew what the problem was. Good luck anyone who gets that issue.

[@RashedHossain]

@@bat__batI’m having the same issue. The car would start up and run fine for couple of minutes and then throw the triangle sign and P0A93 (inverter cooling system performance). I’ve replaced the coolant control valve and drained and bled the coolant by a mechanic shop. Not sure what to do with it at the moment

[@plumkey197]

Did you drain the system beneath the thermos bottle or at the radiator? There's also a block drain valve that should be emptied as well. I just found out about the block drain, so mine wasn't cracked open when I changed the coolant last time LOL. I have found that putting the car on ramps helps to burp the air out faster because the radiator filler neck is the highest point in the cooling system with the front end elevated. Hopefully everyone who does this maintenance doesn't forget to turn the temperature to the warmest setting and the blower on high. Thanks for the video!

[@ColeSloth]

The noise when you shut off the prius has nothing to do with the coolant. It's the brake actuator pump. You also pointed to the inverter coolant reservoir which is an isolated system from the radiator coolant system. To refill the radiator there is a bleed screw at the top of the radiator on the driver side. Opening that up makes getting the air out of the system 10 times easier. As you fill the system while it's running open it up every minute or so to burp it.

[@MichaelJones-hm9of]

How did you monitor the thermostat coolant temp with torque pro? In the prius forums I have read that there is no sensor for that. I have torque pro and have loaded the PIDS to monitor the charging system, 14 blocks, SOC...etc ....but when I look at all available data to add the PIDS I don't see one for the actual ICE coolant temp. I've been told that the dial you are looking at is not actually the ICE coolant temp but rather the reservoir which should come up real fast within a minute after a cold start but it is not the actual temp of the engine at all.

[@CtrlAltDefeatTV]

It's the generic temperature pid. It wont be in the toyota section, it's in the general section

[@amazoidal]

I couldn't add PIDs on Torque Pro. So I installed Dr. Prius. A lot easier to use.

[@boobtubeakatv1296]

Yes, Hybrid Assistant has one just for the ICE on the main screen...

[@johnstuart9058]

Thanks for the video. Curious how much coolant you had to refill after the thermostat swap? I’ve read it’s about ~6 quarts lost in this process. I need to change the thermostat and water pump on my gen 2 as well. Thanks

[@JapRapNipHop420]

Hi, theres a coolant bleeder valve on the Prius. It takes a 10mm wrench

[@allenthomas914]

Is this same for my 08 toyota prius?

[@Chris-go9ti]

so it runs at 180 all the time? is the prius not like other cars where it drops and goes back up in temp?

[@Javid_74]

Of course it does, but all parts are designed to produce a certain temperature given the right circumstances, like driving on a flat highway. But sure if you climb a mountain to a ski hill you'll go up, or if it's hot out, or very cold out, it'll change all the time.

[@boobtubeakatv1296]

Uhm.... When the ICE shuts off the engine cools to 130 or less unless you are calling for heat then it only drops to 140... IF your on the highway zipping along, the ICE is running all the time and it acts like a normal non hybrid engine at 180 to 210...

[@bikelifeleaf8889]

did you unbolt the thermostat housing from the top or bottom of the car?

[@MottyRuttner]

how many miles on the car?

[@delinquentdesign]

I think it will run leaner to heat the engine to operation temp if it’s too cool

[@chasederby88]

I dont think so, I lost about 8mpg. Im changing mine rn

[@boobtubeakatv1296]

It ll run richer, like towards choke to heat the ICE up to temp...

[@ponya-2mdfk904]

Thanks a lot bro good session

[@riceburner4747]

Is there a guage that works like torque pro? Or a OBD type sensor? I agree with u! Great video. I subscribed. Id like a guage in front of me. Thnx

[@eXdXgXe4life]

Did it actually make the cabin any warmer or start warming the cabin any sooner?

[@danieladams6849]

How is the Prius do you still have it? How's the HV battery still good??

[@CtrlAltDefeatTV]

I do still have it, about 16 or 17k miles on the pack and it's still going strong

[@hedgehogthesonic3181]

@@CtrlAltDefeatTV And now how is it doing?

[@joepaullawncare7222]

That pumping noise you hear is your ABS pump.

[@JosePerez-xu3nk]

Thank you for the Info

[@gman5794]

Put generation 2 in the title

[@MajidAlbassam]

The phone you are using is it iPhone?

[@CtrlAltDefeatTV]

I'm using an android with TorquePro

[@toddsaechao4484]

Too much of talking. Get to the point.stop respecting your self.

[@southerngunner-y7o]

The coolant you are putting in the radiator has nothing to do with the hybrid side , 2 different systems they are not connected.