Is it critical to change coolant at 100K?

[tmontague]

Originally Posted by komichal

Just a few notes from me:
- before you start draining out the coolant, set the cabin temperature knob to max
- by draining the coolant via the radiator petcock you will not get out everything. I can drain slightly over a half of the coolant only. There is a petcock on the engine that allows you to extract some additional liquid but it is a rusty one - IMHO not worth it (it is like 2-3 dcl only), especially when there is no chance to lift the car up
- I am draining and refilling the coolant once a year. I know it is waaaay too often, however it is a 20 minutes easy job and this way the "old" coolant that stays inside the car has no chance to get "too old".
- I agree that original Toyota coolant is naturally the choice number 1. However, I do not use it. I use Sheron Antifreeze G12 which can be bought already 50/50 mixed and the bottle costs around 7 USD (4 times less than original Toyota stuff). This Sheron product won in the test of several other brands available locally and it matches the specs required by Toyota.

good points - although I never understood everyone saying to put the heat on high. All this does is move the flap so the air passess over the heater core instead of bypassing it. This has no effect on coolant running through the heater core.

Have there been some past cars that had some sort of coolant heater core by pass when the hvac is set to cold air only?


It seems that a handful of manufacturers have come out with Toyota specific (Asian brand) coolant in the last couple years. Originally when I purchased my Yaris around 5 or so years ago, there really wasn't much options for aftermarket coolant other than green "universal" unicorn tears.

[komichal]

Originally Posted by tmontague

Have there been some past cars that had some sort of coolant heater core by pass when the hvac is set to cold air only?

I used to drive some older Mitsubishi and it really used to have some electric-controlled valves that enabled or disabled the coolant flow through the heatcore. It is probably pointless for Yaris, you are right. It is just an old habit that does nothing wrong on some cars and does something right for other cars. :)