UK / Europe Prius 2 Coolant Change

https://attachments.priuschat.com/attachment-files/2021/06/206709_How_to_Replace_Gen_II_Prius_Engine_Coolant.pdf

 

^That's a very nice document, likely more complete/clear than Toyota's Repair Manual. Anyway, just for a cross-check, I've attached repair manual excerpts (added the inverter instruction, just in case).

 

It sounds like you don't have the coolant heat storage tank in the UK. But you should have a drain on the radiator part of the system not the upper inverter cooling radiator but the lower engine ice radiator push comes to shove just undo the bottom hose coming out the bottom of the radiator assembly that'll drain it pretty much by gravity as it's the lowest point in the system if you're doing all this coolant changing you might be changing a few hoses and then when you put them all back together just take your time and fill it slowly that's about all you can do with the generation two unless you have one of these vacuum filling devices that speeds the process up but reality about it is pouring it in slowly doesn't really take that long you want to put in the recommended volume and that's about it

 

@Lee Tomlinson, follow the instructions in the document linked by PriusCamper but ignore all steps that fuss with the coolant heat recovery tank. The drain and refill is much simpler without it. You may feel like, "Well that was too easy!" because it is. Just remember to check the level at the radiator filler neck every day for a week then maybe once a week for two weeks until you're satisfied all the air is out. For this time you can leave the upper engine cover off.

Best of luck.

 

If you take your multi-tool and you cut off just that little half circle that covers the better portion of the radiator cap you'll be able to remove your cap the rest of the car's life now with that cover in place I never have to move mine anymore You can't even tell that it's been trimmed You can do it with the utility knife carefully and you can't even tell the factory didn't do this now that panel can stay until you have to remove the radiator play with the fans or something I'm just saying if that's appealing to you then you don't have to pop all those little clips up their pictures online I've done it to every car I don't take the panel off to do it I do it while it sits right in place it just takes a second now I can remove the radiator cap on all four cars without pulling any pins or any plastic That's a good thing

 

On our Gen 3 the repair manual instruction says to drain the block, via a spigot on the back/right corner of engine. Hard to get to.

I thought give it a try at least once, even though I’d read lots of comments about it being a waste of time. It was a waste of time: got at most 1/2 a cup for all that effort.

 

Correct.

Yes and yes, on the radiator.

Yes, it is on the inverter roughly opposite the radiator bleed valve. The inverter drain and fill is the same as on US cars and is easy and straightforward.

Correct, not a lot comes out of the engine block drain.

Nope, the thermostat is not a sealed unit and has enough clearance to allow coolant to drain when cool/cold.

 

I drained the coolant, on our Gen 3, with cold engine. For what it’s worth, not sure if it would make a difference.

 

I've never used the inverter bleed valve on the generation too mine just sits there I have an opened it on all four of the cars ever I've replaced all the pumps and the coolant obviously comes out when you take the pump off unless you clamp it in and I just dumped the cooling in the reservoir turn on the car and usually it's standing there with the jug squeeze the hoses and hear the thing start to gurgle and bubble and take on water and then top off the tank see the water moving close the hood and forget about it there's no place else for any to be The little loop is very tiny so that's that I have never had to crack the bleed valve for the inverter ever with a mag drive pump you shouldn't really ever have to It should just pump the fluid right up where it needs to go air and all

 

I got 4.25 liters drained, following the same regimen. From my log:

- engine coolant drain: 4.25 liters roughly
- inverter coolant drain: 1.5 liter roughly
(verify both, with note in garage)
- negligible amount drained from engine block drain, not worth doing in future

Maybe spilled some??

 

Ah woops, I've got a gen 3. Could well be different.

I think it's best to do on a cold engine. IIRC, it's good to have the heater set to a high temp, helps it drain. Not totally sure about that, but seems logical.