2008 Kubota BX23 engine in BX25 Temp Gauge Stuck pinned HOT

[Russell King]

@pgrovetom

Since you seem to be electrically oriented and you (or someone) mentioned LEDs, could you use the existing gauge and embed a few leds into it? Maybe three to six LEDs and set them off at different temperatures and color code them?

Basically a digital/analog type of gauge. I think I have seen some on modern car dashes.

 

[pgrovetom]

@pgrovetom

Since you seem to be electrically oriented and you (or someone) mentioned LEDs, could you use the existing gauge and embed a few leds into it? Maybe three to six LEDs and set them off at different temperatures and color code them?

Basically a digital/analog type of gauge. I think I have seen some on modern car dashes.

Yes I thought of that and might end up doing that. The reason is mounting a clumsy gauge on a tractor with no logical place that often gets rained on is a problem. I thought of just doing the circuit I already showed and by adding a simple comparator like an LM393 and 3 LEDS for maybe Blue or white =cold, Green = in safe range and Red for too hot. I could just put them inside the existing dash which is waterproof and located in front of the driver. Not a bad method. thanks... It eliminates the mechanical gauge mounting issues which is messy. Its all I need to know anyway. I could even but a small buzzer alongside the red LED as an audible Hot warning. This might just be the best solution. I could just tap the existing temperature sensor voltage entering the dash and calibrate my LEDs for appropriate voltages for cold, normal and hot.

 

[GreensvilleJay]

curious, found these, Amazon probably have them as well...

18mm 20mm 22mm 24mm 1 8 npt hose adapter water temp joint - Temu Canada

deals on 18mm 20mm 22mm 24mm 1 8 npt hose adapter water temp joint pipe sensor aluminum temp gauge radiator temperature system temperature monitoring durable joint precision fitting adapter cooling system part on Temu. Shop on Temu to start saving.

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$5 CDN...... 1/8" NPT. To me it's the simplest solution, leaves original sensor in the block, YOUR 'upgrade' is 100% independent of the original wiring and such.

just checked amazon.ca, 2x the price to $54 !! for same piece !!!

 

[pgrovetom]

curious, found these, Amazon probably have them as well...

18mm 20mm 22mm 24mm 1 8 npt hose adapter water temp joint - Temu Canada

deals on 18mm 20mm 22mm 24mm 1 8 npt hose adapter water temp joint pipe sensor aluminum temp gauge radiator temperature system temperature monitoring durable joint precision fitting adapter cooling system part on Temu. Shop on Temu to start saving.

www.temu.com

$5 CDN...... 1/8" NPT. To me it's the simplest solution, leaves original sensor in the block, YOUR 'upgrade' is 100% independent of the original wiring and such.

just checked amazon.ca, 2x the price to $54 !! for same piece !!!

Don't actually understand what you are suggesting.

I'm already bread boarding the 3 LED circuit - to put inside the dash where the temp gauge is. I put my dash back together and installed it in the BX25. I measured the existing temp sensor cold and it was 9 volts. I let the BX25 warm up and the voltage quickly dropped and stabilized at 1.75 volts - when the thermostat opened. That suggested to me to light the Blue=cold LED above about 6 volts. Light the Green = normal LED at about 5-1.5 volts and hot = RED LED at less than 1.25 volts. I have a replacement BX25 sensor coming from Amazon. I'll repeat that test to be sure those values are ok with the new sensor. I already changed the thermostat. If not its easy enough to tweak some resistors to adjust the ranges. I'll hide the small bread board PCB under the dash and run the 4 wires for the LEDs up into the dash. Drives for Blue, Green, Red LEDs and fused +12v. This approach leaves the dash alone ( except the tiny LED board) and leaves the sensor alone.

I realized measuring the water temp outside he engine and not Block water temp is risky. If the BX25 lost its coolant, the outside block/head water sensor wouldn't work. But the existing sensor is screwed into the head which will get hot even if the water is gone or not flowing.

 

[xrocketengineer]

Did you check with mountainman for a spare instrument panel working or not working?

 

[GreensvilleJay]

I didn't realize you'd reuse the existing sensor and others were NPT ,so the 'rad hose' adapter looked like a simple solution.
Both temp and fuel circuits will have a voltage regulator on the high side( typically 10 volts ) allows for better more accurate and stable readings. The WSM should have a chart of resistance vs temperature.
I use bowl of water on stove to slowly heat up sensors with a know calibrated themerometer close to the sensor. That way I can plot the sensor's actual response.

 

[Joe.G]

Does anyone have pictures of the Different style gauge clusters used over the years in the BX25 Series? I believe my tractor is and 2014 and looks like the one in the picture I believe or it was used for more than a few years.

 

[pgrovetom]

Did you check with mountainman for a spare instrument panel working or not working?

 

[pgrovetom]

I tried. No response.

 

[pgrovetom]

Does anyone have pictures of the Different style gauge clusters used over the years in the BX25 Series? I believe my tractor is and 2014 and looks like the one in the picture I believe or it was used for more than a few years.

I believe its this one at the Messicks website https://www.messicks.com/parts/kubota/K2771-99000#locator

 

[Joe.G]

Mine doesn't look like one in the link.

 

[xrocketengineer]

I tried. No response.

Give him some time.

 

[Russell King]

I tried. No response.

If you want to, try to contact him on this site now that the holiday is over tomorrow!

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