Old B7100 - adding a temp idiot light

JRHill

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Orange: B7100 Std and Woodmizer; Green/yellow JD Buck, Gator and 410j.
Apr 26, 2016
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Wahkiacus, Washington
Approximately a 1984 B7100. Has anyone added an idiot light for temperature? I don't need a gauge/sending unit - just a light on the console. But I don't see any plug or accessory location that a sending unit could be installed.

It's gonna be another hotter than normal summer. (but what is normal these days?)
 

North Idaho Wolfman

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You're going to need to add a temp sending unit adapter, it installs in the upper radiator hose.
Then you'll have to find a sensor that trips at the proper temp (that's the hard part).

Like this, but Probably in a smaller hose size.

Or something like this will do the job.

 
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GreensvilleJay

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curious, grabbed the WSM... NO thermostat.. aka 'thermosiphoning ' system...
neat 'inline well adapter' ... but,well this is nuts....

$5 cdn....sensor,wires,meter..

You could 'gear clamp' it to the upper rad hose ? bolt to the water pump ?? While more than an 'idiot light', you'd know the coolant temperature and see IF ti was going up to 'critical'.
Yes, overkill but yeesh $5 !!! 1/2 the price of the 'well adapter' and I bet a Klixon is more AND you still need a light on the dash. re: Klixon.. what temperature should it be ?

hay, it might be an option for you ??

heck clamp one on both the upper and lower rad hoses, see the difference in temperatures, you could figure out when the rad's getting plugged up.... :)
 

JRHill

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Orange: B7100 Std and Woodmizer; Green/yellow JD Buck, Gator and 410j.
Apr 26, 2016
59
11
8
Wahkiacus, Washington
Thank a bunch for the ideas folks!

Mr. Wolfman I found the right switch but there's no way to get it in the short upper hose and the bottom hose has an in-line engine heater in it, darn it. If there was one in a 90 degree I'd be set... Come to think of it I recall the farm store has 1 1/4" barbed steel 90 hose/tubing connector. Just tap 1/8 NPT and I'd be good to go!

Jay, you gave me an separate option. I could easily use one of the studs on dyno cover/upper coolant hose connection. You're right, it wouldn't be actual coolant temp but I'd sure know when to take the load off of it with the RPMs run up a little to cool it down. All I'd have to know is what the display showed normally and do a cool down at, say, 160-170F?

I've never overheated the 'lil rig with backhoe or loader work. It's mainly when pulling a long steep grade between sites. Please don't think I'm being silly. This old rig is getting a bit weak and I really baby it so it will out live me.
 

GreensvilleJay

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You might want to pull the rad and 'chemically ' clean it, maybe flush the block as well, while you're trying to plumb in some kind of sensor. An 'ounce of prevention' deal ?
At one time I had a copper 1.25" Tee fitting where the stub as 1/2", one of those odd ball WHAT could I use this for fittings ? If (if ?) you had room, maybe something similar could be put into service ? Maybe some 'boiler heating' piping ??
options and think 'outside the box'......
 

kubotasam

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Thank a bunch for the ideas folks!

Mr. Wolfman I found the right switch but there's no way to get it in the short upper hose and the bottom hose has an in-line engine heater in it, darn it.
I have one of the fittings like North Idaho Wolfman suggested installed in the upper hose on my B7100. I don't think my tractor is any different than yours.
 

85Hokie

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I too installed one many years ago - bought a new radiator hose just to be safe - measured 5 times and cut once!;)

1678841938816.png

1678841984629.png


works like a charm!
 
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85Hokie

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. All I'd have to know is what the display showed normally and do a cool down at, say, 160-170F?
I would not be "guessing" at other metal connectors as to how hot there are - I would take the temp DIRECTLY from the coolant at the head or in the upper radiator hose. An idiot light tells you typically that you are already in the danger zone whereas a gauge will tell you when to slow down.

As for temps at top of radiator - you WANT to get that machine hot, like 210 at top hose - and yes make sure you are cooling via radiator - lower temps should be less than 100.
 

JRHill

Member

Equipment
Orange: B7100 Std and Woodmizer; Green/yellow JD Buck, Gator and 410j.
Apr 26, 2016
59
11
8
Wahkiacus, Washington
OK Hokie. It is the same. I was gonna ask if someone could take a picture of the fit-up so thank you. I think I'll go with the red one (wink). Is that a Kubota hose and P/N? Where did you put the gauge so its not hanging down under the console to snag your boot?

Frankly my upper hose really needs to get changed out... I am definitely going in this direction now.

Appreciate you guys!
 

North Idaho Wolfman

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Pull the hose off yours and measure the diameter and get the fitting that fits.
That is not a Kubota hose that's aftermarket, just walk into a auto parts store with your original hose and have them match it up.
 
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North Idaho Wolfman

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I stand corrected, the hoses that I got for my B7100 were still the cloth covered hoses.
 

JRHill

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Equipment
Orange: B7100 Std and Woodmizer; Green/yellow JD Buck, Gator and 410j.
Apr 26, 2016
59
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8
Wahkiacus, Washington
I too installed one many years ago - bought a new radiator hose just to be safe - measured 5 times and cut once!;)

View attachment 97973
View attachment 97974

works like a charm!
Got it rigged up and tested. It's holding with no leaks. I did have to shorten the cast housing a bit so it didn't kink the hose even with the formed 90d bend. Somehow my radiator is a little lower that in the picture. Now I have to find the darned idiot light that is up in the shop somewhere and wire it up which is a cakewalk.

Thx again for the pix.
 
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#40Fan

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Jul 21, 2022
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Make sure that you run a ground wire to the adpater fitting.

But, I'd remove that from the upper hose and put the sending unit in the block somewhere. If the T-Stat sticks closed, you'd never know.
 

trial and error

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I'm curious on the outcome of this setup, the parts used and links to get them, I have two brand new rad hoses waiting to be installed on my b7100 but if this whole setup works I may look into it before installing them. The whole thermo syphon system on these things makes me nervous especially now that I've added a loader. I've never had a "boil over" but i feel its inevitable some day. Amd this may help prevent it
 

85Hokie

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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
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I'm curious on the outcome of this setup, the parts used and links to get them, I have two brand new rad hoses waiting to be installed on my b7100 but if this whole setup works I may look into it before installing them. The whole thermo syphon system on these things makes me nervous especially now that I've added a loader. I've never had a "boil over" but i feel its inevitable some day. Amd this may help prevent it
It all works perfectly = and the only thing wrong with the thermosyphon system is that physics always works all too well, thus the operator must stay on top with the little things like keeping the radiator clean and whatnot.

Make sure your hydraulic radiator is also taken good care of - as you are going to increase the hydraulics temps.

TEE FITTING

GAUGE and FITTINGS

double check the fittings before buying
 
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6869704x4

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Jun 29, 2011
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I would rather have an alarm.
The overheat indicator on my 49 8N is when it blows boiling coolant on my face.
 
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slyoteboy

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B7100HST
Nov 26, 2023
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Y'all that have installed the temp gauge in the upper rad hose on the b7100, what kinda temps are you getting? im consitently showing 220+ while working it, Is that normal? Doesnt matter hot/cold outside, if im working it its in the red. Radiator never loses coolant, and it aint spewing out.