New owner 06

Semiconductor efficiency of the Inverter & pump efficiency of contaminated fluid.

Buy gallon of Toyota SLLC. Put sample in clean clear jar. Put sample of your Inverter tank in clean clear jar.
Compare quality of coolant.

Note level of turbulence in Inverter reservoir. Compare that to new fluid turbulence.

Btw, none of that matters anyway because your overdue for suggested change of it anyway. Instead of replacing sensors that are working replace the suggested maintenance schedule items which is Ice and Inverter Coolant at 100K miles.

 

The ICE is not hard on the coolant and at 100K usually looks pretty good. You can get around its major hassle of air lock by doing a few repeated dumps of the rad only and avoiding the dreaded airlock. Air bleed of the ICE coolant is a major pita. Dump rad and overflow and re-fill. Drive it for a week and intermittently turn on the heater once in a while to circulate old coolant through heat core. Do this 3 times and that's almost as good as a full flush.

But the Inverter with its seemingly miles of pure aluminum cross sectional heatsink channels for cooling and the transmission cooling chamber tend to cause aluminum contamination of the Inverter coolant. My car's Inverter coolant looked degraded at 30K and showed a great benefit to Inverter coolant change as evidenced by the IR thermometer checks before and after. Mileage jumped up a little and stayed up. And its very easy.

The Inverter is the workhorse heart and soul of the car. It deserves some special attention once in a while.

Good Luck!

 

I'd like to replace the ICE coolant pump and thermostat on my G2 Prius as a preventive maintenance.

Any hints where to pinch to let me replace the parts without introducing air ?

 

Air lock wise replacing the ICE pump is a problem as coolant will run out of engine block.
No way really to stop it. And air gets trapped in the top part of the engine the cylinder head.

If my ICE pump was not weeping I would not change it. Best way to maintain it though is to dump the rad and refill with fresh coolant a few times as new coolant has better heat transfer and anti-corrosion benefits and will extend pump life.

If pump is weeping your in it. Please refer to Patricks post about jumping out the CHRS bottle pump relay as air will not bleed out of system without intermittent cycling of that pump.