Heater cant “keep up”

[405Runner]

Kind of a weird prob so wanted some 2nd opinions.

My heater works fine when its better than 40 or just sitting parked.

But once it gets around freezing and I start driving my heater blows likewarm at best. Not cold per say, but its def not warm at all. Im thinking its the thermostat acting up but since Ive never seen this before, Im kinda confused.

Put a piece of cardboard in front of the my radiator and drove around but it didnt help at all, so makes me think maybe the thermostat is stuck open just a bit or something.

Anyways, any opinions are appreciated. Its cold in Oklahoma right now lol. 6 degrees. Need heat bros.

 

[brillo_76]

Antifreeze level good? I suspect I stuck thermostat open.. Could also be an actuator stuck as it's a 2001 is digital climate controls. We are down to 3 here..

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[405Runner]

I have manual controls, didn’t get the cool options.


Yep I just redid my antifreeze a month ago the PO had just put straight water in it lol.

Think Ill just put a new t stat in and see what happens.

 

[alumarine]

Could be your thermostat, the heater control valve on the firewall or heater core is plugged.

With a 180 thermostat I get 160 degrees F out of the vents when the outside temperature is 11 degrees F.

On really, really cold days sometimes it's better to run the fan on medium speed not high.
On high the cold air flow can reduce the heat from the heater core too much.

 

[brillo_76]

I like my rear heater on days like this keeps my seats warmer.

What sucks is that it's hard to be outside in the wind when it's like this. The winds and windchill are high so don't get frost bite.

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[jgue467]

Heater control valve is suspect, mine has gone thru 3 OEM ones in 12 years, though all had the same symptom, leaking fluid right from the front where the valve is. Maybe yours is stuck partially open not allowing enough fluid thru.

I've driven mine in 2 degree weather, hot as can be coming out of the vents....

 

[desertegal7]

assuming your engine coolant temp is within the normal range i would suspect:
1. control cable to the valvle is loose thus not opening properly. you can tighten it up. i did mine but to over close the valve since it was not fully closes resulting in less efficiency when running ac.
2. heater core may be clogged buy if the valve opens it will unclogge itself eventually.
3. heater core maybe full of dust and dirt. you can check it with endoscope via mobilephone.

 

[desertegal7]

also its not a good practice to put anything in front of the radiator.
what's you temp gauge pointing at? it should be slightly below middle, you can also grab a Bluetooth obdii adapter and hook it up to your phone, engine coolant temp should never go below 80°.

you may straightly just replace the thermostat if engine temp is lower than 80° when driving.

 

[405Runner]

Is the heater control valve the valve on the center firewall?

Yes my temps run just below center.

When I get home Ill check it all out.

 

[jgue467]

Is the heater control valve the valve on the center firewall?

Yes my temps run just below center.

When I get home Ill check it all out.

Yes, smack in the upper center firewall.

Might want to get a more accurate temp readings via something like Torque Pro ($5) and a BT odb2 reader to connect to it.

 

[brillo_76]

Plus switch ro recirculating your air. That way it's only heating the cab air

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[alumarine]

Plus switch ro recirculating your air. That way it's only heating the cab air

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Depending on where you live that will ice up the inside of the windows very quickly.

 

[nissanh]

Previous owner used just water, so I suspect your heater core is clogged. You get heat due to few channels are functioning. Most clogging can be of corrosion and or Calcium carbonate built up. since you are in OK, I suspect your water is hard water just like my area. If none works for you, try doing this:

1) Disconnect both heater core hoses (DON'T use pliers to loosen the rubber hose attached to Aluminum tubes, the plier can bend these tubes, USE a pick to break the bond between rubber hose and Aluminum tube)

2) Use 9% vinegar (some grocery store will sell this ratio), and fill the heater core with this vinegar. Leave few hours. I usually attach two separate hoses to heater core lines and use those tubes to fill and flush the core. You may see random bubbles coming out through the hose, that's CO2 produced during the reaction of CaCO3 and vinegar.

Then flush with water, look for chunks of CaCO3. Repeat...

I did this to clear the clogs in my 2000 Land Cruiser: I did this over 2 week period, fill, leave, flush every 2-3 days.

 

[brillo_76]

Previous owner used just water, so I suspect your heater core is clogged. You get heat due to few channels are functioning. Most clogging can be of corrosion and or Calcium carbonate built up. since you are in OK, I suspect your water is hard water just like my area. If none works for you, try doing this:

1) Disconnect both heater core hoses (DON'T use pliers to loosen the rubber hose attached to Aluminum tubes, the plier can bend these tubes, USE a pick to break the bond between rubber hose and Aluminum tube)

2) Use 9% vinegar (some grocery store will sell this ratio), and fill the heater core with this vinegar. Leave few hours. I usually attach two separate hoses to heater core lines and use those tubes to fill and flush the core. You may see random bubbles coming out through the hose, that's CO2 produced during the reaction of CaCO3 and vinegar.

Then flush with water, look for chunks of CaCO3. Repeat...

I did this to clear the clogs in my 2000 Land Cruiser: I did this over 2 week period, fill, leave, flush every 2-3 days.

I have a heater core that needs cleaned out. Thank you for posting .

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[brillo_76]

Depending on where you live that will ice up the inside of the windows very quickly.

Well I did this today at -5 degrees to get enough heat out of the heater core that I need to clean.

I had ice on the inside until I did this. Being it was only heating up semi warm air the cab got warmer. Which cleared my windshield and my side windows all ice inside and out dissappeared.


It can't snow below 10 degrees only flurry as the air can not hold much moisture below this point. So correct it does depend on the situation.

Being the OP is in this same situation I was today it will work provided the cab air has some heat in it.

It's a lot easier to bringing air temp up from 30 degrees then then -5

I can tell you from my experience today it worked and I will be cleaning my heater core very soon.





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[3bears]

i think a lot depends on where you live. one of the posts above says dont put anything in front of radiator....well they live in yamen and i live in the complete opposite as far as temps. If i dont block the radiator...im screwed...as well as many up here. we have to run block tranny and oil pan heaters at least 2 if not 3 hours before doing a remote start for at least 15 minutes. regardless...a correctly working heater control valve...or thermostat should help most of you...if not try flushing the system to hopefully clear any obstructions in the heater core...another tip...pull the fuse that runs the ac..as it will kick on to dry the air to help defrost...but it also kills a bit of heater time... ive learned over the years in my location it makes a difference...
and keep the engine from revving up and down when it kicks on while sitting there idling to warm up....matter of fact..i no longer have a belt to my compressor as even in summer i dont use ac up here.
but all locations are different...if yamen or alaska...and what works for you is what works....after eliminating mechanical failures

 

[brillo_76]

i think a lot depends on where you live. one of the posts above says dont put anything in front of radiator....well they live in yamen and i live in the complete opposite as far as temps. If i dont block the radiator...im screwed...as well as many up here. we have to run block tranny and oil pan heaters at least 2 if not 3 hours before doing a remote start for at least 15 minutes. regardless...a correctly working heater control valve...or thermostat should help most of you...if not try flushing the system to hopefully clear any obstructions in the heater core...another tip...pull the fuse that runs the ac..as it will kick on to dry the air to help defrost...but it also kills a bit of heater time... ive learned over the years in my location it makes a difference...

and keep the engine from revving up and down when it kicks on while sitting there idling to warm up....matter of fact..i no longer have a belt to my compressor as even in summer i dont use ac up here.

but all locations are different...if yamen or alaska...and what works for you is what works....after eliminating mechanical failures

I was doing 2 to 3k idles to get heat. Right now the 2 days it's been more your Temps here. The main issue here is the wind it won't let up keeping our wind chills fairly cold. Good to hear from old 3 bears. Hoping all is well.

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[alumarine]

...another tip...pull the fuse that runs the ac..as it will kick on to dry the air to help defrost...but it also kills a bit of heater time...

If working properly the a/c compressor should not kick in below approximately 25-30 degrees F when in defrost mode.

 

[3bears]

If working properly the a/c compressor should not kick in below approximately 25-30 degrees F when in defrost mode.

than mine must not have been working corrrectly, as it would kick on even at minus 20. you could here it kick on and the engine speed up

 

[405Runner]

Guess the plan is to do the flush and go ahead and change the t-stat. Who knows if the PO used the old one, put it in right, whatever. So, too easy. That'll be the plan next weekend, supposed to be 60 instead of 6.