Capacity: Inverter & Engine Coolant

Gen II is:

Engine Coolant 9.1 quarts
Inverter 3.9 quarts

And yes add to the overflow it works its way in.

 

I wasn't able to find a spec for the inverter/transaxle coolant. I think that 2.9 quarts is about right, as I recall using ~3 quarts when doing a drain and refill.

Regarding the engine coolant, although the spec is 9.1 quarts, when you are doing a drain and refill the actual amount used will be more like 6 quarts because a good portion of the coolant is retained in the heater core and hoses. Therefore, you should capture the drained coolant and measure it so that you know how much needs to be added before you can declare victory on your project.

Regarding topping off the engine coolant, I suggest that if you are checking the coolant level because you've recently drained and replaced the coolant, then you should also remove the radiator cap when the engine is cold and check the fluid level directly in the radiator.

In principle fluid added to the reservoir will eventually make its way into the radiator assuming proper functioning of the radiator cap. However, depending upon how low the fluid level is in the radiator, you may be better off directly filling the radiator to the top of the neck, rather than counting on the overflow reservoir to eventually fill the radiator.

 

I do not think that you can remove the radiator cap without first removing the black plastic cover.

 

I agree with Patrick it's a lot easier to get access to the radiator cap if you remove the radiator cover, and it doesn't take very long to do. That said, I have been able to remove the radiator cap and make a quick check of the fluid level in the radiator by removing just the two leftmost clips and pulling gently up on the radiator cover far enough to get access to the radiator cap...

 

It has not been mentioned, but, there are a few precautions that you have to be aware of, such as: air bleeding procedures, drain locations on BOTH coolant systems. To avoid repeating all this, Do a search on PriusChat, and read everything first.