Most likely cause of 2004 Yaris no warm air from vents

[WhatYarisitAgain]

With these cars is a no warm air from vents situation most likely caused by the air mix flap being disconnected/flexing, linkage to the flap being stuck, or more likely to be a clogged heater core requiring flushing?

[SirDigby]

what year is this car? where is your coolant level? what kind of coolant do you have? what does the coolant look like? does the temp gage feel loose/turn easy? did you check cable attachments?

[WhatYarisitAgain]

It's a 2004 Yaris. Coolant is kind of rather just somewhat rusty orangey color water. Temp selector doesn't feel loose, but rather clicks (or ratchets) I I think I can hear the flapper working when it gets to all the way hot or all the way cold.

I topped it off with more water and I'm getting slightly (very slightly) warmer air out of the side vents, and much faster and unheated air (and much faster flowing) air out of the center vents. So I closed the center vent louvers and I can feel like I said very slightly heated air from the side vents and maybe in the defroster vest when I have it set to defroster.

I am going to flush the heater core with a garden hose by disconnecting both ports just now.

[WhatYarisitAgain]

An update:

I flushed the coolant and now just have plain water in the system. I flushed the heater core too. I'm now getting somewhat more heated air from the two side vents, but I'm not getting a lot of high speed air volume from those two side vents. Two two center vents have a lot of volume but the air isn't heated coming from them.

Any advice on that?

Also, I can't figure out out where the bottom vents are...in other words when you use the vent selector knob to point toward your feet, are there really feet or knee vents? I don't see any or feel any air coming out.

[dogsridewith]

See if moving the hot-cold control knob is moving the water valve.
(Is there a water valve? Some muscle era Detroit cars didn't have one. 91 Corolla does.)

[WhatYarisitAgain]

Originally Posted by dogsridewith

See if moving the hot-cold control knob is moving the water valve.
(Is there a water valve? Some muscle era Detroit cars didn't have one. 91 Corolla does.)

I think these cares have a constant flow through the heater core, and therefore they wouldn't have a valve but I really am not sure. I'm totally not an expert.

[thebarber]

park front end pointing up a steep hill let take the cap off coolant overflow to let the air bubble out. i bet you have air in the heater core

[B.B._07]

I agree with thebarber that you most likely have air in the system which is preventing you from getting good heat from the heater core. To bleed the air out of the system you need to let the car idle with the radiator cap off until you don't see anymore bubbles coming up. It should take at least 15 or 20 minutes to do as the thermostat needs to open up to let the coolant circulate and let the air out. You'll know the thermostat is open when both the upper and lower radiator hoses feel warm to the touch. Raising the front end of the car or parking at an incline will help get the air out faster. These videos go over it very well:

https://www.youtube.com/watch?v=nThsFGa1vuE

https://www.youtube.com/watch?v=zUpXgAJ1gjU

Also even if you're in a warm climate you don't want to run pure water in the cooling system for the long term as it lacks the anti corrosive additives found in coolant/antifreeze.