Serious Help Need with a 1997 Land Cruiser – Refuses to Give Heat

[thebigdog]

Serious Help Need with a 1997 Land Cruiser – Refuses to Give Heat.

I am at the end of my wits, and need HELP from a Toyota Guru.
My truck is a straight 6 cly. And has only 120K miles.
It has run perfectly for me for many years, giving excellent heat.

One cold day out of the blue, it just started giving cold air – both front and back blowers.
I have changed the thermostat with an OEM one; I have flushed the heater core.
There was no water flow restrictions found.
I have checked the valve in the engine compartment, and it operated properly.
I have checked the blender flap, inside the truck under the blower, it works fine.

I have checked the heater tubes in the engine compartment, going in and out of the heater core.
The inlet is very hot, but the outlet from the core is slightly colder.
The red anti-freeze in the radiator is very hot to the touch.
I just don’t want to change the heater core needlessly, since I see no blockage or leaks anywhere.
I honestly cannot think of anything else to do.

Can anyone help me – PLEASE, I love my truck but I have to have heat in it this winter.
Have I missed anything to check, or is there a hidden temperature control I don’t know about?
Someone help me - PLEASE

 

[Kigiin]

You can live without heat, it's A/C you must have living in OH.

Oh, wrong forum.

 

[scottm]

Perhaps a moderator can move this to the 80-series forum where many gurus can probably answer this question. Of course they'll first need to determine if it has factory lockers.

Until then, I wonder if the cabin temp sensor could fail and cause this? Does this truck have an "auto" button in the center of the heater control panel?

 

[Hoosier Daddy]

You're sure the rear heater is also blowing cold? The rear has its own separate heater core, so that's very important.

How did you test the mixing valve in the engine compartment?

Is your truck a 40th Anniversary edition?

 

[CycloSteve]

If it is a 40th with the "Auto" temp controls (like the LX450), there is a bypass switch IIRC on the back of the control panel. Search, and ye shall find a few threads on overriding the automatic system, returning it to manual.

If not an auto temp system, my money would be on the heater valve in the engine compartment not opening fully (or at all), or an air-bubble in the system.



Steve

 

[wasnt me]

Check the valve in the engine compartment again.
Ive seen the cable come off the valve and not allow the valve to open and thus no heat..

 

[excessive]

also try temporarily bypassing the valve to make sure that's not it

 

[scrowley]

I would say your first prob. was probably the thermostat and now you have air in the system. It took my cruiser about 20-25 min with the cap off, front of truck elevated slightly, heat on, to get all the air out and get good heat. OR Like everyone else said heater valve under hood. bypass see if it changes before replacing. If the water hose going into the valve is hot and the output side is cold you almost know its the valve (you might see the cable moving valve but could be internally broke)

 

[pnolanIH8MUD]

For my 97, the heater valve was closed and there was air in the system. It continues to take a while for the heat to come in, especially when both upper and lower and rear systems are going. I also found a metal eyelet on the floor of the right front passenger area so I think a cable broke. If you at least manually open the valve (gently) you can probably get some heat. Be careful though not to force the cable.

 

[thebigdog]

Negative, no auto button

Perhaps a moderator can move this to the 80-series forum where many gurus can probably answer this question. Of course they'll first need to determine if it has factory lockers.

Until then, I wonder if the cabin temp sensor could fail and cause this? Does this truck have an "auto" button in the center of the heater control panel?

 

[thebigdog]

Disconnected it, and manually moved the lever.
I eye balled the door inside - it operated perfectly.
I'm positive that the back blower only had cold air.
I'm aware that their two separate units, this has me baffled too.

Unknown about 40th Anniversary


thanks

You're sure the rear heater is also blowing cold? The rear has its own separate heater core, so that's very important.

How did you test the mixing valve in the engine compartment?

Is your truck a 40th Anniversary edition?

 

[thebigdog]

It moves fine and the valve is working fine

thanks

Check the valve in the engine compartment again.
Ive seen the cable come off the valve and not allow the valve to open and thus no heat..

 

[thebigdog]

Second time - maybe a charm ?

I did a second extra long flush, of the entire system.
The heater core hoses, and two in the passenger side firewall.
I even flushed the radiator, used a high pressure water hose.
I also flushed out the engine block.
I saw no crude or rust coming out, and water flow was excellent.
I replaced the red antifreeze, and started the truck.

The temp gauge moved slightly, amd I tried the heat.
It was WARM, both front and back heaters.
When the temp gauge made it half way up the gauge,
I Had Excellent heat, both front and back.

I'll know in a couple days, if the heat will stay operating.
Strange how it just decided to work on it's owm.
Maybe it was a Gremlin, and he moved to a new SUV.

If you guys don't hear back, within the next three days,
Then I say it is FIXED !!!!!, the Gremlin has moved on

I'd like to thanks everyone, for their time and suggestions.
Thank You All...

 

[grizzlygibbs]

So the moral of the story is you likely had an air bubble in the system.

 

[sandyford]

It may sound too elementary, but your coolant may simply be low. I went through that - felt pretty stoopid when I figured it out.