Heater and temp questions (1 Viewer)

[Malleus]

 

[Malleus]

When I asked about the scan gauge I was really wondering if feeding the extra cable underneath the dash might have put something in a bind affecting perhaps blend door operation.

I doubt it, but anything's possible

 

[Malleus]

Since you posted your heater circuit temperature observations, I was curious what mine were, since my heater operates as expected.

First, my 1995 80 has 124,777 miles on an engine to which regular maintenance has been done (replace hoses, belts, oil, and a few seals), but nothing has been done to either the front or rear heater circuits, except installing a new control valve, about five years ago (plastic ages whether it's used or not).

Observations were made after about an hour of in town driving. Ambient air temperature = 65°F; operating coolant temperature, after driving, at idle (about 650 rpm; A/C was not used) heater valve closed = 181°F/ heater valve open = 183°F (according to Torque Pro II). FWIW, I know my thermostat operates properly; it was tested about six months ago, and the engine temperatures have remained consistent since then.

Here are the photos of the heater control valve actuator, closed (approximately 29 mm of cable exposed) and open (no cable exposed).

 

[Malleus]

Here are the temperature observations with the heater valve closed, and then with the valve open (note the coolant flow is from driver's side to passenger's side).

I'm not trying to assert that these observations are normal, in spec observations, they're just what I see when my engine is running. The observations are probably most useful when you compare the temperature differential between the closed and open valve positions.

 

[Malleus]

And, just for laughs, the heater core outlet hose, heater control valve closed, and then the valve open.

 

[flintknapper]

Not sure what the OP considers "Hot" but my vent temps today (not cold here) are about 158° F at the center vent (fan on low).

Top of my radiator (engine well warmed up) at about 190°F (vehicle sitting still and at idle).

My heater valve lever from completely closed to completely open moves about 1"

Temp at Heater Valve about 163°F

The hose that the OP says is only luke warm on his unit is about 171°F on mine. You won't hold your hand on that for long.

Note: The above numbers are for comparison only. I do NOT hold these to be the correct temps for the heating system. It's just what mine were today at 65°F ambient (vehicle warmed up, sitting still and at idle).

 

[Herrett]

Thanks gentlemen. Bought the clear hose and connections today. Going to try and get to it tomorrow.

 

[Herrett]

Work kept me from tackling this today. Tomorrow I don’t want to install any T’s. Can’t I just remove one of the hoses from the heater control valve and substitute it with a clear drain hose and then disconnect the hose I’m pointing too and replace with my clear input hose connected to the water hose and back flush? If that will work, which hose on the heater control value should I remove? And how should my temp control slider be set, pushed clear to the right (hot) I assume. I don’t want to flush this crud into my motor so what keeps it out of the other hose still connected to the heater valve? Sorry for being dense on this.

 

[flintknapper]

Work kept me from tackling this today. Tomorrow I don’t want to install any T’s. Can’t I just remove one of the hoses from the heater control valve and substitute it with a clear drain hose and then disconnect the hose I’m pointing too and replace with my clear input hose connected to the water hose and back flush? If that will work, which hose on the heater control value should I remove? And how should my temp control slider be set, pushed clear to the right (hot) I assume. I don’t want to flush this crud into my motor so what keeps it out of the other hose still connected to the heater valve? Sorry for being dense on this. View attachment 3254867

Are you only wanting to back-flush the heater core and not lose much coolant/antifreeze?

Whatever you flush (heater core or entire system) use LOW water pressure.

Do you have a way to measure your vent temps before flushing the heater core? Just curious what it is.

Even a small thermometer would work well enough.

You won't need your heater until Thursday.....looks like. I'd just go fishing, you're right there at the Lake.

 

[Herrett]

Thanks for the reply Flintknapper. I would like to see some of your flint work sometime if you do knap tools and arrowheads. Can you verify or guide me on what hoses in my pic I need to attach from an input output perspective. I will also locate a temp gauge tomorrow. Thanks!

 

[Samuel642000]

Try this

Heater Core Flushing - OWNED!

Now that cold temps are coming, I am reminded how puny the heat is on my truck. The rear seems pretty good, but front vents, suck-a-lo-fogus heat. So after reading and researching, looks like a proper heater core flush/clean is the thing to do (I have burped system already, little increase in...

forum.ih8mud.com

 

[Herrett]

I have read that thread over 5 times I must just be inept as I still cant id the right hoses and i dont want to use Ts

 

[bhsdriller]

Where are the T's you mention? First pic in that thread shows where you need to connect your flush lines
Connect to 1 or 2 and flush as needed

 

[bhsdriller]

Your line off the heater valve isn't stock but this is what you need to do.
Temp controller slider doesn't matter since you're taking the heater valve out of the equation when flushing

 

[RC51]

I assume your heater has been working in the recent past. If it hasn't, your troubleshooting flowchart will be much longer, including verifying that the heater core isn't blocked. There's one thing that every Land Cruiser does really well: make heat.

Your scanguage isn't the problem. The heater isn't electrical. The dash control is, see below.

Check the operation of the heater valve on the firewall. You'll need the key on to perform this check, but you do not need the engine running.

You'll need someone to move the temp lever from cold to hot and back while you watch. Most likely, the valve isn't opening fully. You should see about two inches of cable travel, more or less. If you see only about an inch, the valve isn't opening fully. As a temporary fix, you can disconnect the cable and move the valve manually. Do not attempt to move the valve operator (the lever arm) without first disconnecting the cable. You'll damage the opposite end operator and the interior control is electronic.

Your engine temps are OK. The thermostat being stuck open will not be a problem; that condition will only make it warm more slowly. If it's stuck closed, or doesn't open fully, you'll have engine overheating problems.

If your heater valve, on the engine side firewall, is opening and closing fully, your problem is a damper gate malfunction. The complete heater system description, troubleshooting and repair procedures are in the Resources section, as a separate FSM download.

This is great info! I was wondering why my FSM didn't mention the blend door at all. If you don't me tapping int your expertise...

If I park my truck outside in freezing temperature, and try to move the heat control left and right, I can hear a slight grinding noise, I would get like a second a hot air before it goes cold again. After driving for a while and playing with the heater slider it will eventually blow hot air.

I suspect it's the Air Mix Servomotor AC-42 where the blend door is arm grease is gunky....

To access this part its says I have Remove Instrument Panel BO-76 <--- This shows the whole dash getting pulled apart lol

Do I have to do all that to get access to the Air Mix Servomotor? Or is it someting I can access by removing the AC control unit? Thanks

 

[elbobino]

You can see the servomotor just by pulling the radio out. It will be on the top. It is difficult replacing with radio removed only, but it can be done. I have been dealing with a similar heat issue to yours and have given up getting it to work. Interested to see yours getting fixed.

 

[Malleus]

This is great info! I was wondering why my FSM didn't mention the blend door at all. If you don't me tapping int your expertise...

If I park my truck outside in freezing temperature, and try to move the heat control left and right, I can hear a slight grinding noise, I would get like a second a hot air before it goes cold again. After driving for a while and playing with the heater slider it will eventually blow hot air.

I suspect it's the Air Mix Servomotor AC-42 where the blend door is arm grease is gunky....

To access this part its says I have Remove Instrument Panel BO-76 <--- This shows the whole dash getting pulled apart lol

Do I have to do all that to get access to the Air Mix Servomotor? Or is it someting I can access by removing the AC control unit? Thanks

AFAIK, the dash panel has to be removed, as per the FSM instructions. It looks like a lot of work, but it's not. The first time I did it, it took less than an hour to remove and reinstall.

I've never tried to access the heater system components without removing the dash. You may be able to access it, for inspection only, by just removing the lower panel (the one with the controls in it), but, and it's been a while since I did this, I don't think you can reach everything you need to this way.

 

[RC51]

AFAIK, the dash panel has to be removed, as per the FSM instructions. It looks like a lot of work, but it's not. The first time I did it, it took less than an hour to remove and reinstall.

I've never tried to access the heater system components without removing the dash. You may be able to access it, for inspection only, by just removing the lower panel (the one with the controls in it), but, and it's been a while since I did this, I don't think you can reach everything you need to this way.

Thank you for that info. I thought it was a 10+ hour job to take it all out.

As long as it's above freezing the blend function works fine. I may just wait until the summer.

 

[Malleus]

Thank you for that info. I thought it was a 10+ hour job to take it all out.

As long as it's above freezing the blend function works fine. I may just wait until the summer.

FWIW, I've done this in the winter, inside the cabin. It's really not that hard.

I do advise, whenever you decide to tackle this to do two things first:

Remove both front seats and the consoles. 20 minutes.

Print the entire dash removal FSM pages, single side, and have on hand a divided container, or as many containers as there are fasteners listed in the FSM. It's impossible to remember where each screw is supposed to go, and some will only secure the correct position, while others will fit into more than spot. 10 minutes.

30 minutes well spent and you won't have to take anything apart more than once.

I highly recommend buying a Vessel JIS cross point screwdriver (you need the 100mm model). Hozan are OK, but I really like the Vessel Megadora. Don't waste your money on any other brand. They will strip your screw heads and wear down in no time.