inverter coolant: 120k or 150k?

if it looks dirty replace it

 

My owners manual had it at 150k.

That’s what I would do.

 

From the 2012 Warranty and Maintenance Guide, in a footnote:
"Initial engine coolant replacement at 100,000 miles/120 months. Replace every 50,000 miles/60 months thereafter.
Initial inverter coolant replacement at 150,000 miles/180 months. Replace every 50,000 miles/60 months thereafter."

also in that document:

"Drain the cooling system and refill with an ethylene-glycol type coolant"

and

"Your Toyota is equipped with Genuine Toyota Super Long-Life Coolant. The replacement intervals for engine coolant recommended in this booklet are based on replacement with Genuine Toyota Super Long-Life Coolant or similar high-quality non-silicate, non-amine, non-borate ethylene-glycol coolant with long-life hybrid organic acid technology (i.e., a combination of low phosphates and organic acids). If another type of ethylene-glycol coolant is used, replacement intervals may be different."

 

Take a looksee under the hood.

Look at the coolant reservoir, should have a sticker on it mentioning it.
Might be on the underside of the hood too.

 

FWIW, my Toyota Canada maintenance info make no distinction, says to replace both at 10 years or 160,000 kms (100,000 miles), whichever comes first. However, someone overlooked the sticker on the side of the inverter reservoir, which says to replace inverter coolant at 150,000 miles. Maybe the awkward footnote instruction in the US Warranty and Maintenance Booklet eluded them?

I'll probably stick with changing both, at 10 years, which comes waaay ahead of the kms for me, lol.



The Toyota Canada maintenance instructions have gone through some "interesting" transformations in the last few years too. For our 2010 model year, you get a very tricky-to-read summary of the maintenance, and it encompasses EVERY Toyota model. It almost drives you to create a chart.

Around 2014 they changed to an excellent graph format, with services down the left column, and time/kms across the top row, and it's ONLY for the Prius.

Then, maybe with the advent of 4th gen Prius, they completely stripped maintenance schedules from the Warranty and Maintenance Booklet, say nothing. All the schedules are in an awkward, event-by-event format, online only. And you can't see the full schedule, you need to enter months or kilometers, and it responds with what's needed. So if you've got about 8 hours, you could go through it, make a chart.

@Tideland Prius have you noticed this?

 

I generally change them at 100k or if they are a salvaged vehicle at any milage or on an engine swap. I always flush out the system and make sure to carefully bleed the air out as not to get the inverter pump code P0A93

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