KD-409 rad temp gauge... puzzled...

JohnDB

Active member

Equipment
M4500DT
Jun 9, 2018
376
63
28
NZ
Greetings, does anyone know what the point of this thang is and how it is supposed to be used? I can't find any info about it on the 'net. Thank you.
KD-409 rad temp gauge face.jpg
KD-409 rad temp gauge probe.jpg
 

GreensvilleJay

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Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
9,923
4,068
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Greensville,Ontario,Canada
my guess...
remove rad cap, insert, start tractor, run for say 10-15 minutes, read the temperature ?
 
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JohnDB

Active member

Equipment
M4500DT
Jun 9, 2018
376
63
28
NZ
my guess...
remove rad cap, insert, start tractor, run for say 10-15 minutes, read the temperature ?
Could be, I don't have any better idea. I don't get the "winter range" "summer range" "all thermostat" sections, or why "winter range" is hotter than "summer range". It just seems totally bass-ackward to me. I wondered if it was supposed to be held in the air stream downwind of the radiator and fan... but that doesn't explain the ranges either.
 

GreensvilleJay

Well-known member

Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
9,923
4,068
113
Greensville,Ontario,Canada
maybe ....

In winter, the air temperature is colder.... so when you shut tractor off, it'll cool down quiker "
In summer, it's hot, engine can't cool down as fast, excess heat in block could do damage ??
 

JohnDB

Active member

Equipment
M4500DT
Jun 9, 2018
376
63
28
NZ
maybe ....

In winter, the air temperature is colder.... so when you shut tractor off, it'll cool down quiker "
In summer, it's hot, engine can't cool down as fast, excess heat in block could do damage ??
Might be on to something there. The lowest range is labelled "Install thermostat" so it may be for engines or something else where a thermostat was an optional item. Could that have been the case for old automotive or stationary engines?
 
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The Evil Twin

Well-known member

Equipment
L2501, LA526,
Jul 19, 2022
2,392
2,313
113
Virginia
Wow! I haven't seen one of those in forever!!!
I was only a kid, but my grandfather had one like that. My vague memory is that it was used like this:
To check the thermostat operation you would push the blunt end up against the lower rad hose leaving the block.
Coolant will be hotter leaving in the winter because the thermostat would be mostly closed. The cold air would "overcool" the coolant. The Stat would throttle flow way back and the coolant would pick up more heat per gallon of water since the flow was lower. Lower gpm but more heat per gallon.
Summer is sorta reverse. Warmer air wouldn't cool the coolant as much. The Stat would be open more. Leaving coolant wouldn't pick up as much heat per gallon but there were more gpm through the block.
The "install thermostat" meant your Stat failed open. Time to install a new one.
Remember, back in the yesteryear, radiator fans were motor driven and most had no clutch. They always were spinning. Definitely no electric fans.
 

JohnDB

Active member

Equipment
M4500DT
Jun 9, 2018
376
63
28
NZ
Wow! I haven't seen one of those in forever!!!
I was only a kid, but my grandfather had one like that. My vague memory is that it was used like this:
To check the thermostat operation you would push the blunt end up against the lower rad hose leaving the block.
Coolant will be hotter leaving in the winter because the thermostat would be mostly closed. The cold air would "overcool" the coolant. The Stat would throttle flow way back and the coolant would pick up more heat per gallon of water since the flow was lower. Lower gpm but more heat per gallon.
Summer is sorta reverse. Warmer air wouldn't cool the coolant as much. The Stat would be open more. Leaving coolant wouldn't pick up as much heat per gallon but there were more gpm through the block.
The "install thermostat" meant your Stat failed open. Time to install a new one.
Remember, back in the yesteryear, radiator fans were motor driven and most had no clutch. They always were spinning. Definitely no electric fans.
Hope it brought back good memories! Can I clarify something though, you mention "lower rad hose leaving the block" I sort of feel that the lower rad hose would be leaving the radiator, and entering the block, like the flow of coolant. Is that what you mean? It's the upper hose where flow leaves the block. Thanks!
 

The Evil Twin

Well-known member

Equipment
L2501, LA526,
Jul 19, 2022
2,392
2,313
113
Virginia
Hope it brought back good memories! Can I clarify something though, you mention "lower rad hose leaving the block" I sort of feel that the lower rad hose would be leaving the radiator, and entering the block, like the flow of coolant. Is that what you mean? It's the upper hose where flow leaves the block. Thanks!
Lol!! Yes! Upper hose. Total brain fart on that one.