My heater used to work great...

Now the air it blows is cold-room temperature at best

if i turn it off for a minute and turn it back on i get hot air for a second and then it goes cold again...

any ideas? possible causes and solutions?

Check your coolant level?

Does the water Temp gauge reach the middle quickly or not?

If not, probably thermostat gone. That's pretty common....

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no, its actually been running cold lately. so that sounds like the thermostat?

its been getting up to around 1/3 at the most, been around 1/4 most of the time though

So your thinking the thermostat is stuck open and the water isnt getting hot enough?

where is our thermostat located?

This post has been edited by Stu37363: Jan 14, 2009 - 3:15 PM

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Definitely thermostat. It gets stuck open, so all the water is free to go into the radiator.

Not 100% sure where it is located on your engine, but on the 3S-GE, it's just below the alternator, follow the top radiator hose into the engine block, and it's there.....

Someone will confirm.

Not a difficult job.

Thanks, ill see if i can replace it and let you know if it worked.

What color antifreeze do i need? i was doing some research and didnt realize it was so complicated... i think i have yellow or green in there now.

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Toyota used red coolant, but you will be ok going back with green they are the same and green is alot cheaper. To confirm manphibian, yes the thermostat is below the alternator, you will see a plastic or aluminum neck the bolts to the water pump, remove it and the thermostat is sitting right htere (assuming you still have the 5S-FE).

This post has been edited by silver6gc: Jan 14, 2009 - 5:57 PM

replaced the thermostat last night...

Engine is heating to temp and staying there now ...

Heat is a little better, but not even close to what it used to be.

Could old antifreeze or air in the lines affect the heaters efficiency? im pretty sure there is some air in there still, but i thought it would work itself out...

im not sure what to look for at this point, any more ideas?

flush the coolant system to get rid of rust and deposits.. there are some off-the-shelf products available to DIY.

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yeh you dont want an airlock in your radiator did you fill it up with one of those fast fill things (havent seen one before) but it prevents air getting in there. Check your radiator if its cold at the bottom then u have air in there or could be the other way round sorry been ages since i had this problem. Im sure if u have air in there it will over heat, sorry i cant be more help but thats something to look for.

you probably still have air trapped in the system, specifically the heater core.

take the radiator cap off, turn the knob to full hot, put it on th vents, turn the fan speed to low.
start the car and let it idle, it'll push out some coolant don't worry.
keep it idling until both radiator hoses are HOT, one will stay cold for a while and one will get warm faster, the cold one is the one you're waiting for, it'll get as hot as the other one with the thermostat opens. by now your heat should be wamr

once the thermostat opens your coolant level will probably drop in the radiator and it'll bubble some air out, refill the radiator to the neck and put the cap on and continue idling the car, by now your heat should be hot. let it idle until the radiator cooling fan comes on and then goes back off. turn the engine off and let the car cool down for 2-4 hours, make sure the coolant reservoir is full, as it will draw some coolant in. after its cooled go re-check the reservoir and add coolant as needed, put it slightly above the hot level.

start the car and let it warm up then go for a spirited drive with the heat on, some additional air may purge from the system so keep an eye on the temp gauge. again, let the car cool and recheck the coolant level.

your heat should be hot, your cooling system free of air, and your car should be much more enjoyable.










now, for hecks sake this is the 3rd of 4th time i've posted how to do this, can someone make a sticky?