Accuracy of temp gauges?

DrCharles · Nov 23, 2017

I have a 70D with what looks like the original temperature gauge. It doesn't register any more, even when bush hogging heavy weeds/saplings. Engine is definitely getting warm though

So once again I thought I might roll the dice with another Indian gauge copy. Although shipping is slow, for only $15 delivered the price is good and it looks nice.

However... at my altitude (1004'), water should boil at 210F. This gauge stabilizes at 200 when the sensor is immersed in a pot of boiling water. So I'm not super impressed with the accuracy, or lack thereof.

Just wondering how accurate anyone has found their JD gauges to be, and if I should even worry about it. I do run a 50/50 antifreeze and water mix, and with a 180 t-stat, I wouldn't expect to ever hit 210 anyway (all I basically use the tractor for is bush-hogging). thanks.
-Charles

Dan in Ohio · Nov 23, 2017

Charles,

Get your gauges from Jerry Trcka (EverGreen Restoration) and they will be accurate. I use an infrared temp gun to check engine temp. My 70D's must all have t stats that open about 170, now my gas 70 is a different story. I put a 195 degree stat in it a couple years ago and I do not think it has opened since. I thought the diesels were the cold blooded ones. Jerry Trcka phone 715-635-8629, cell 715-520-7876.

DrCharles · Nov 23, 2017

Oh, I'm sure Jerry will sell me an accurate temp gauge, but probably not for $15

Diesels are more thermally efficient than gas engines, so when lightly loaded I would not expect them to be pushing the limits of the cooling system. But the lowest marked division above the pin is 140 and all our tractors had better be getting at least that warm. If the t-stat is not open, the coolant temp should keep rising until it does open!

Or does your gas 70 have a radiator shutter like my 50 does? No idea if it ever opens either...

620 John · Nov 24, 2017

That's what my cheap gauge does too, stops at 200 F at about 1000' sea level in boiling water. I'll just have to make sure the needle doesn't get above 190.

James Howell · Nov 24, 2017

"[b:654c4848f0][i:654c4848f0]does your gas 70 have a radiator shutter like my 50 does?[/i:654c4848f0][/b:654c4848f0]"

None of our Model 70 gas tractors have shutters.

Take a look at the [b:654c4848f0]Radiator[/b:654c4848f0] diagram below.

Hope this helps.

James Howell · Nov 24, 2017

"[b:654c4848f0][i:654c4848f0]I wouldn't expect to ever hit 210 anyway[/i:654c4848f0][/b:654c4848f0]"

We have used both of our Model 70 diesels, "<a href="https://youtu.be/My_-rJrC2FI">Big John</a>" and "<a href="https://youtu.be/0UJaC-r3plU">John W</a>", to power a KRONE 260 round baler during the Summer here on the farm in NE Texas.

The temperature gauges on both tractors "appear" to be original and will register.

Neither of the two tractors have ever overheated in 100o plus temperatures.

We also use the 50/50 antifreeze/water mix in the radiators.

Hope this helps.

Kent Petersen · Nov 26, 2017

running an engine with a gauge that is not right is about like driving with a blindfold on if you can.t afford a good gauge you should not be restoring tractors

DrCharles · Nov 26, 2017

That's your opinion, which you are welcome to although I completely disagree.
No one said I couldn't afford it.
Nor have I ever indicated that I was "restoring" this tractor or any others. I want it functional and don't care if it's concours-ready! You'd probably have a fit if I told you that the very old 13.6-38 rear tires (that were on it when I bought it in '00) are two different makes, too. Should I now go out and spend $1200 or so just to make them look better?

And how exactly does knowing that the gauge is 10 degrees low, by actual measurement, equate to driving blindfolded which obviously doesn't work at all??

jwitty · Nov 26, 2017

Those indian gauges your talking about...if it's on eBay I'd stay away from him. If you look at the reviews, at first glance they look amazing, until you see that 95% of the reviews are the same person lol. I tend to stay away from them because more likely a scammer selling crap stuff and no returns if it's bad. Go to a better known site.

buickanddeere · Nov 27, 2017

the lightly loaded diesel is blowing heat up the stack with the unused air from too lean of combustion operation. . The stat can be fully closed and the engine will never warm up.

DrCharles · Nov 28, 2017

Diesels almost always run very lean except at wide-open and full load, since they don't have a throttle. Lots of intelligent
commentary here https://www.researchgate.net/post/What_is_the_stoichiometric_A_F_ratio_in_diesel_engines2 (and many other places).

But I never considered that "air cooling" could work so well under light load! How much of a load would you say my 70D needs to
get the engine up to 180F? All I've got right now is my bush hog since I had to leave a disc and 2-bottom plow behind in a move
years ago.

Accuracy of temp gauges?

DrCharles

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Dan in Ohio

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DrCharles

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620 John

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James Howell

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James Howell

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Kent Petersen

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DrCharles

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jwitty

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buickanddeere

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DrCharles

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