'99 100 series no heat (1 Viewer)

[nodaksn3]

Got my sunroof and driver's door window fixed and trying to figure out why I can't get any heat. The blower works fine, a/c works great but no heat comes out when the temp is turned up. I first noticed this late Spring this year on the annual trek from Phoenix to Massachusetts. My first thought was the air-mix servo might not be working and I've been dis-assembling the dash in anticipation to getting it but now with most things taken out I'm wondering how much further I have to "dig" into the dash. I've checked all of the fuses and they are all ok.
Q: Does the relay in the kick panel of the passenger side have a role in getting heat?
Any advice would be appreciated.
Thanks. I thought the sunroof was tough but this is a real puzzle.
Ned

 

[60 toy ota]

you should be able to hear that servo/linkage move. Doing this with the engine off makes it easier to hear. does your rear heat work? are you getting up to temp? does the air get any warmer with the fan on a low setting?

 

[nodaksn3]

Rear heat works I normally run with that on so the interior isn't too cold (it's chilly here in Phoenix). The servo is now exposed (but not reachable as it's sandwiched between the cowl side and the fan box. It's to the right side of the fan box) and I can see that it's not moving when heat is turned on.

 

[aroq]

you should be able to hear that servo/linkage move. Doing this with the engine off makes it easier to hear. does your rear heat work? are you getting up to temp? does the air get any warmer with the fan on a low setting?

I noticed you mentioned the low setting.....what is that about?

I ask because that is all I get from the heater. If I turn it up more, it just gets colder. Curious about this heater issue as well, but living in San Diego I don't need it much,

 

[60 toy ota]

I noticed you mentioned the low setting.....what is that about?

I ask because that is all I get from the heater. If I turn it up more, it just gets colder. Curious about this heater issue as well, but living in San Diego I don't need it much,

It's a classic symptom of a clogged/restricted heater core. If only a small amount of coolant can flow through the core, it is very limited on the amount of heat (energy) it can output, even if the coolant itself is hot (think in terms of a candle which burns at over 1000 degrees, vs an oven set at 300 degrees- which puts out more heat?)

The same amount of heat ENERGY is being drawn out of the heater core by the moving air, regardless of the fan speed. the difference is that the higher fan speed dilutes that small amount of energy over a higher volume of air, lowering the net temperature.

Flush your heater core and get the coolant flow proper, which will provide more heat for the fan to draw out

 

[aroq]

It's a classic symptom of a clogged/restricted heater core. If only a small amount of coolant can flow through the core, it is very limited on the amount of heat (energy) it can output, even if the coolant itself is hot (think in terms of a candle which burns at over 1000 degrees, vs an oven set at 300 degrees- which puts out more heat?)

The same amount of heat ENERGY is being drawn out of the heater core by the moving air, regardless of the fan speed. the difference is that the higher fan speed dilutes that small amount of energy over a higher volume of air, lowering the net temperature.

Flush your heater core and get the coolant flow proper, which will provide more heat for the fan to draw out

perfect, I'll try that. Thank you.

 

[Mike NXP]

How bought the basics, is your coolant in reservoir and radiator full ? I suppose since your rear heat is working fine that your fluid is probably ok but worth a look. How about engine operating temps, is it getting up to proper temp?

 

[jflavell21]

Hi did you ever get this sorted out?

 

[dealmaker]

No shortage of threads in MUD... google search heater core 100 series landcruiser ih8mud forum

I'm in the middle of resolving mine w/o backflushing the cores. Instead, I'm flushing my coolant system and using ThermoCure. About done with the ThermoCure phase and planning on running and flushing numerous times w/distilled this weekend. Already, the heaters are back to cranking out heat again.
Here's what I'm doing, and only because I replaced the heater tee's and hoses a few yrs ago. Otherwise, I'd backflush the cores. So...if you need to replace your heater tee's and hoses, now's the time to do it along with backflushing the cores (multiple times) Please help with overheating 2007!! - https://forum.ih8mud.com/threads/please-help-with-overheating-2007.1312365/#post-14961374