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Discussion Starter #1
I recently picked up an X495. For a while I thought the temp gauge wasn't working at all as it tended to always stayed just into the green without moving. This was when running or not running. I just figured that the meter wasn't working at all and I knew this was a common problem with this tractor.

Today I ran the mower for a while at about the highest RPM and operating the 62" deck. After a bit of that the temp gauge showed much higher. Still in the green, but not too far from the upper red zone.

I'm just trying to figure out if this is fairly normal? I want to have some confidence in my temp indicator but these two extremes leave me wondering.
 

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You did not state year or hours on the machine. Did you change ALL fluids after getting it? If not, I would change your coolant, check your thermostat for operation, make sure the screens are clear on the radiator and blow the radiator fins clear too.
 

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My x595 normally runs a little in the green at operating temp.If your running close I'd check things out as stated above.
 

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Discussion Starter #4
Thanks guys. So you agree that this seemed to be running too hot. It sure seemed so to me.

It has just over 600 hours. I did check the screens and the coolant level. I did not change the coolant. I have every reason to believe that it has been serviced appropriately. I'll double check all the airflow & coolant again. Given it's jump from near zero to what seems to be high I'm suspecting the temp gauge operation. I know the instrument cluster has a reputation for acting up.

Does anyone know what voltages should be seen going to that temp gauge? If I had that I could check the gauge operation out.
 

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There is some information in the attached document starting on page 180...showing the range of resistance of the temp sender:

The engine coolant temperature sensor is a variable
resistor, providing a ground circuit path for the temperature
gauge. As the engine coolant heats, the resistance
decreases. As the resistance decreases, more current is
allowed to flow across the engine coolant temperature
gauge causing the needle to rise and indicate a higher
temperature. The temperature gauge is part of the
instrument panel.
The engine coolant temperature sensor resistance is
approximately 40 - 700 ohms.

...and the nominal voltage at the panel gauge when engine is not running:
3. B2 Engine CoolantTemperature Switch -- 6.0 to 7.0 volts

Test B2 Engine Coolant Temperature Sensor (See Temperature
Sensor Test).
If the switch is OK and the P2 Coolant Temperature Gauge
does not operate correctly, replace instrument panel.

Here is the section excerpt of the document:
View attachment X495 electrical op and diag from TM2024.pdf

...Bummer if you have to replace the dash module...looks really expensive!

Chuck
 

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Discussion Starter #7
Ok I seem to have figured this out. First, yes I double checked the coolant level and that the screens were clear. Unlikely that I really had elevated engine temperature.

I picked up a 1k pot so I could reproduce the 40-700 ohms stated in the tech manual quoted by Chuckv above. I connected power (pin 17) and ground (pin 20) to the connector and the pot between ground and the temp input pin (pin 2). When I adjusted the pot I got movement on the temp gauge but the needle position wasn't always proportional to the pot setting. That seemed to reproduce what i was seeing with the "jumping" gauge while it was in use.

So I took it all apart. I pulled the instrument cluster open, took 4 screws out and got the PCB out. I inspected it carefully for broken solder joints and that sort of thing, and I noticed that the pins on the back of the two instruments were a bit corroded. After trying a few other things I just cleaned those up with some very fine sandpaper and everything works now. Here are some pics for future reference:

Here's the PCB where the instrument plugs in...
IMG_20190404_204627.jpg

Here's the back side of the instrument. These are the pins I cleaned up to make better contact...
IMG_20190404_204910.jpg

I can't say that I'm highly confident that this fix will last. Some conductive compound may help that.

NOTE: Don't use dielectric compound/grease or Vaseline on these contacts.
 
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