The Factory recommended 15000 mile checkup suggests that the coolant be replaced. My experience says 3 years at least why 15999 miles?
Factory? or dealer. Dealer recommend service much more than the factory does. Pretty sure toyota uses extended life coolant, 3-5 yrs between changes
It’s cheap insurance. The manufacturer recommends it, so why not? They must have some reason. I’ve always used the two-year schedule because that is the average life of the anti-rust components. But, there must be something.
And, like I said, it is cheap insurance.
I don’t know why Toyota recommends that the coolant be replaced sooner on a Prius than on their other models, but I think that you have to accept that the engineers found a good reason for this recommendation since manufacturers love to be able to show minimal costs for maintenance of their vehicles.
So, rather than questioning the reason for the 15k interval, I think that another question is in order. Do you want to preserve your warranty coverage on this car? If you do, I suggest that you follow the manufacturer’s maintenance schedule, and keep records of the maintenance.
We all want to minimize costs, but in the long run failure to follow the manufacturer’s maintenance recommendations will likely lead to higher expenses for repairs that might have been avoidable. And, if your warranty is voided, that could be especially painful.
Factory? I thnk not. Maybe your dealer, or else you got the incorrect scheduled maintenance guide…
Coolant is run through both the engine and inverter, but same reservoir tank.
US scheduled maintenance guides: http://smg.toyotapartsandservice.com/
2001-2003 US Prius has the engine and inverter coolant changed every 30,000 miles/2 years.
2004-current US Prius has the engine and inverter coolant first changed at 100,000 miles/10 years, and then every 50,000 miles/5 years thereafter.
Why the difference? Different coolant choice by Toyota between model years.