Water Temp Sensor - More Information is Good
Quote:
Originally Posted by
gmwillys
In regards to your water temp gauge conundrum, 2.8k is way to high
I don't know the gauge scheme on the M38A1. I am assuming that as the engine gets hotter, the sensor resistance goes lower, more current flows through the gauge and the needle goes upscale toward 200+ degrees. I also am assuming that the gauge is still a bimetal thermal gauge.
Now that the engine is cool, clip lead the sensor back in place and see what it reads. If our guess about how things work is correct, the needle should hardly move at all.
2.8K seems high for a cold sensor, but again, this is a 24-volt system and we'll learn something from this experiment. AT least now we know that there is not an internal short in the sensor that pegs the gauge.
In the '48, we managed to damage the oil pressure gauge. Someone (?), probably the shop goat, dinged up the oil pressure sender and shorted the gauge to ground. (You know, that goat that walks through the shop at night and takes things off benches, eats up pans full of screws and little parts and generally causes havoc). That short warped the gauge innards - it reads about 20 PSI with the engine off and 50+ PSI with oil pressure on the engine. That's a project this winter.
If the sensor lead to the gauge was grounded, the gauge could have been damaged.