No heat unless...

[Pinchlite]

If I start the car I dont get heat untill throttle is touched.

The car can sit firever idling but heat will not come out untill I tap the throttle.

Never encountered this on any car before.Once the heat comes it is at normal hot temp.Could be thermostat issue?

UPDATE:

May be a faulty waterpump.I will try and findout how to diagnose and see if this issue.

[myfirstyota]

Also check coolant levels.

[Pinchlite]

The white plastic container in back of the radiator seems to be at proper level.

I have read that air trapped could cause improper heat.

[myfirstyota]

That's exactly what I was thinking. Let the engine cool and pop the "rad cap". See if there's coolant in the hose.

[Pinchlite]

I dont not see coolant with cap off.I thought that was normal seeing reservoir was at normal level.

[myfirstyota]

I think the air in the system doesn't allow proper flow of the coolant resulting in inadequate flow to the heater core. When you hit the gas, I'm guessing the water pump spins faster and forces some coolant to the heater core.

But that's my guess...

[Pinchlite]

I read you can take cap off and start engine to eliminate air?

Cold engine of course.

[myfirstyota]

Yep. Top off coolant, Run engine till fan kicks on, top off again and cap on. That's how I bleed the air in my engines... unless there's a bleeder valve which I dont think the yaris has.

[nortonfb]

Try squeezing hoses to help circulate and remove air. Fill radiator
to bottom of neck. Any excess will go to tank. Cap radiator after steady level is maintained.

[Pinchlite]

Yep. Top off coolant, Run engine till fan kicks on, top off again and cap on. That's how I bleed the air in my engines... unless there's a bleeder valve which I dont think the yaris has.

I did this and heat is tip top!

Just curious wait till fan kicks on?

[myfirstyota]

That's when you know for sure the thermostat has opened. That allows the coolant to flow through the engine pushing the air bubbles to the top of the system, which in the yaris's case is the 'rad cap'. Thus purging the cooling system of any air.

[Pinchlite]

thermostat has opened

Okay.Makes sense know.