We have a 2012 Toyota Prius with 85,000 miles on it. When we had an oil change and checkup at the dealership this April the dealership mechanics strongly recommended that Inverter Coolant and Engine Coolant be replaced. Based on the age of the car, they said it was time. I don't necessarily have everything taken care of for our Prius at the dealership, and so I called a local mechanic for a quote on what replacing the Inverter Coolant and Engine Coolant would cost. This local mechanic (who is extremely reputable) told me that you don't need to think about replacing the coolant in a Prius until at least 120,000 miles. He therefore told me our Prius did not need to have this done. So, who is right? Does a 2012 Prius need to have the Inverter Coolant/Engine Coolant replaced every 10 years or so, or not? Thank you for your input.
if you look at your maintenance schedule, it's mileage or months, whichever comes first. if you don't want to spend the money, you should at least test the engine coolant to make sure it isn't eating away at the head gasket, which is a time bomb on your model. and consider cleaning the egr circuit.
Toyota USA recommends to change the engine coolant at 100k miles, or 10 years, whichever comes first. And at first glance, and maybe second and third, the same intervals are applicable to the inverter coolant. And FWIW, that IS what Toyota Canada recommends. But, if you check the referenced footnote “3”: AND make the assumption that the footnote (in TINY print, on the NEXT page) governs: the inverter coolant change is delayed ‘til 150K miles, or 15 years, whichever comes first: My 2 cents: change ‘em both, at 100K miles or 10 years.. Both dealerships and independent shops seem to do their utmost, to avoid any mention of Toyota’s official maintenance recommendations. Sometimes they more-or-less stick to it, sometimes they wildly embellish it. As often as not they’ll make no mention of items that aren’t in the schedule, especially if there’s not much profit margin, but nevertheless worthwhile, or even crucial. examples of worthwhile: Brake fluid change (not mentioned by Toyota USA, but recommended by Toyota Canada every 30K miles or 3 years) Transaxle fluid change (no mention by either North American Toyota corporate entity). At least once. Should not cost over $100 USD. Use ONLY Toyota ATF WS. Example of crucial: clean the EGR (Exhaust Gas Recirculation) components, including the intake manifold. ASAP. This may save you from a blown head gasket. ^ See first two links in my signature for more info. On a phone turn it landscape to see signatures. Of note, currently in the States there’s precious few professional shops that’ll do this, or even heard of it. And Toyota is hoping it’ll “blow over”… replace the water pump and thermostat, “soon”, say by 120K miles at the latest. They have a plastic impeller, that reliably fails, say by 150K miles. there’s another maintenance category: stuff that IS in the schedule, but way too subtle: Brake service, every 30K miles or 3 years. Not just the “visual” inspection. This should entail lifting the calipers off the rotors, clean and relube of pads/shims, caliper contact points and caliper slide pins. And periodically a check of rotor thickness and runout. If I may offer advice: It’s your car, and accordingly you’re the one who has the most to lose, if maintenance is missed, or overdone. Don’t totally rely on dealership or independent shops, or Toyota USA, to tell you what’s good for your car. Consider their advice, but take it with a grain of salt. Check the glove box; there “may” be a copy of the Toyota USA Warranty and Maintenance Booklet lurking in there. If not, pdf version is available for download; Toyota Tech Info is one source. One issue, that booklet’s maintenance schedule is a mind numbing event-by-event format, making impossible to see the maintenance frequencies. I’ve done a spreadsheet table format translation, can post in a few hours. It’s almost certainly how Toyota first formatted the schedule.
And then there’s this, on my 2010 Canadian spec Prius (attached). I asked Toyota Canada about it; they said ignore it, change inverter coolant at 160k kms or 10 years. interesting too: it’s not a ‘merican label, has km conversion and French.
A belated thank you to bisco, rjparker, and Mr. Leisk for your responses. I just recently had both the engine coolant and inverter coolant flushed and replaced. Thank you also for the advice to clean the EGR components.