Temperature idiot light

[Sam27]

I took a long trip in the M1008 today and ran into a situation where the temp idiot light kept coming on. I could pull over, open the hood and wait five minutes and it would go away for a while. I was cruising about 55, but not doing any major hills or anything. I had a few axles in the bed.

I have a few questions. First, where is the temp sensor that runs the light? Is it the same as used by the GP controller? If this was a real overheat situation and not a gauge problem, is it a known issue? Suggestions on what to look at? Thanks.

 

[Barrman]

The trouble shooting section of the -20 manual takes you through how to test the light.

The sensor is on the drivers side front cylinder head.

 

[cliffyp]

You can also take out the existing sender and put one for an actual gauge so you can see how hot you are running all the time. With the idiot light you might be sitting just under the threshold for the light to come on and thinking all is well just because the light isn't on. What temp is the idiot light set to come on at?

 

[Sam27]

You can also take out the existing sender and put one for an actual gauge so you can see how hot you are running all the time. With the idiot light you might be sitting just under the threshold for the light to come on and thinking all is well just because the light isn't on. What temp is the idiot light set to come on at?

Beats me. I hope it's low since it kept coming on. Or maybe the light is just flaking out. The engine bay didn't seem especially hot when I opened it up. Seems to be running okay.

Is it a different sender than the GP controller uses? I ask because I saw a thread somewhere about where to put a "secondary" sender for a gauge. If all you had to do was replace the idiot light, I don't know why someone would ask that.

Also, would you expect overheating just from sustained 55 mph driving with an M1008?

 

[cliffyp]

The sender for the idiot light and the temp sensor for the glow plugs is not the same. The glow plug temp sensor is at the back and the idiot light sender is at the front front. You can't use a gauge with the current sender. If you purchase a gauge and its appropriate sending unit you can remove the idiot sender and put in the new sender. Then just run a wire into the cab to attach to the gauge.

 

[cliffyp]

As to overheating at 55. Your thermostat could be stuck closed so coolant isn't getting circulated through the radiator, your radiator could be clogged or your idiot light/sender could be malfunctioning among other possibilities.

 

[Sam27]

Thanks. I guess the guy in the other thread wanted to keep his idiot light or something. A gauge will be the easiest way to debug this.