Why changing engine coolant more often than factory recommendation matters

Toyota Canada tells me to change both inverter and engine coolant at 160k kms (roughly 100k miles) or 10 years, whichever comes first, then every 80k kms ((roughly 50k miles) or 5 years, again whichever comes first.

I've followed those criteria, change both a couple of times now, last time at 15 years and 105k kms (roughly 65k miles).

 

Good stuff. I've heard, by a Toyota master mechanic, to just cut whatever Toyota service manuals suggest by half...in both time and mileage.

For my 2021 Prius, it says coolant, initial 100,000 miles (160,000 km) or 10 years and then every 50,000 miles (80,000 kms) or 5 years thereafter, I do initial at 50,000 miles or 5-years (whichever comes first) then every 25,000 or 3-years...whichever comes first. (Coolant is one of the easiest services to do.)

My manual says engine oil changes every 10,000 miles or yearly and I've done every 5,000 miles or every 6-months since 2008 in all of our Toyota's. Zero engine/transmission issues in any vehicle. Have had a few items needing replacing but nothing huge. (Alternator in my son's Rav 4, a couple of serpentine belts and sway bars, etc.)

Even though I maintain half a dozen family Toyota's, I've use my scan tool more on the neighbors Saturn and GM!!