Inverter Coolant top-off question

When I got my Prius, I used a Sharpie to mark on both bottles (Engine coolant and inverter coolant loop) the level when cold. Over the years, both have gone down perhaps 3mm

If you want to bring it back up to the upper line, get a premix of SLLC from a Toyota dealer, and slowly add.

Do not dilute the premix stuff with water, and never ever use high silicate "green stuff" coolant. They don't play very well together

 

I added this product to both the radiator and some in the inverter coolant too on my 07. It has excellent anti-corrosion properties especially for aluminum (our inverters) and its main coolant improvement function is as a surface tension reducer keeping the coolant in contact with hot metal much better. It works really really good. Much better than water pump lube.Have not lost a water pump in a car yet running this product and down in Florida you see water pumps fail alot.
Here's a little white paper:

http://www.redlineoil.com/whitePaper/21.pdf

Throw a bottle in the radiator and half a bottle in the inverter.Its red so it matches the inverter fluid.
Its going on my second year in my Prius with this product. Excellent.

 

As with transaxle fluid, Ed is doing unique Prius experiments. Here also I hope you look into the possibility of chemical testing of the fluid when you replace it. It would be great to know if there are any differences compared to SLLC alone.

Are you contemplating different change intervals than the 100k initial/50k subsequent?

 

Use of non-Toyota fluids is not recommended. They may not be compatible with the equipment or with the original Toyota fluids, and if damage results it will be out of warranty.