Changed antifreeze on yaris and now the car is cold even thoe engine is hot

Depending on noise and if it does it more when it's cold, it could be the timing chain tentioner. If it's louder when it's hot, could be engine bearings.

car heater?, does blower blow full speed on high?>
what car, what year? what engine: are you in Siberia>? cant guess, there is cold and horrid freezing, cant guess that.
we uses thermometer called a IR pyro gun
point laser to thermostat housing see 170F, stat is 180F right
I plug in scan tool it shows 180F, good.
i point gun to fire wall heater core hoses, both are hot.
one hot , the core is packed, ever heard of a FULL FLUSH?
both hot,
i make sure the heater damper for tempeatures (red >>>>>blue)
is not stuck in the cold position by careful inspections of DAMPER.

Yes.
The thermostat could be stuck open and by theory thermostats should be changed once a year.

Do the throttle body cleaning and idle speed re-learning procedure.

That is an over temperature indicator. It means your car is running hot.

you still have air trapped in the cooling system. Get front of car as high up as you can on a hill. Cold engine - loosen radiator cap, fill with 50/50 antifreeze mix. Start engine and run until upper radiator hose is hot (thermostat open). Engine should burp air and maybe spill some coolant, that's ok. Once burped, tighten cap, shut off engine and let it cool down while keeping the reservoir full. It will **** coolant out of reservoir as it cools. Keep it full.

If still cold air, take to a shop that has evac/fill equipment; they will **** air out and repalce with coolant. About $80.

gerry

could be low on antifreeze, or if antifreeze is too weak it can freeze up and you wont get any warm antifreeze through the heater core, if its blowing sort of warm but not hot it could be thermostat, and maybe even the hot cold switch is not working

is the engine warmed up,yet?>? if not you shouldt run the engine for a while and then run the heater.
you coukd have a faulty thermostat if that doesnt do the trick...

Hello. The symptoms you describe indicate that your car's thermostat is due to be changed. Go to any auto zone or similar parts store where they will sell you the proper part, and even help you change it. Regards, Joe

If the engine is cold, fill to the cold level. If it's hot, fill to the hot level.