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Discussion Starter · #1 ·
I consistently see the water temp gauge reading in the 160-175 degree range. Had the radiator temp checked by a radiator shop, while idling a couple of months ago with an infra red meter; it showed about 185-190. Anyone know of any reason the car's gauge consistently shows a lower temp? Is this normal, or should I just get a new temp sender & install?

ChiefBre
 

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But Mad North-Northwest
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Could just be a dirty connection. You can try cleaning the terminal in the engine bay.

The monopod temperature gauges tend to be pretty accurate in my experience, so if that doesn't help I'd probably suspect the sender. Unfortunately I do not have the specs on the resistance of the sender vs. temperature to verify that.
 

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I would try replacing the sender first as it is an easy and inexpensive thing to try.
 

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Another thought is to check the system voltage. The sender gives a variable resistance for the gauge's ground path. The gauge requires that the system voltage is in the proper range. If system voltage is off (low) the needle will read low.
 

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If you have the mono gauge pod you can send the unit out and have it recalibrated. Or try replacing it with a different gauge if your new sender does not fix the problem.
 

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Discussion Starter · #6 ·
Another thought is to check the system voltage. The sender gives a variable resistance for the gauge's ground path. The gauge requires that the system voltage is in the proper range. If system voltage is off (low) the needle will read low.
What would be a good reading to conclude that the voltage is low? What should it be? I cleaned the terminal clip
today, and after that my nap got in the way of a test...Do you check the sender with the wire attached to ground to measure?
Chief Bre
 

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What would be a good reading to conclude that the voltage is low? What should it be?
Connect a voltmeter to the battery. With everything off a fully charged battery should show 12.6V. With the engine running (alternator charging) it should increase to between 13.6V & 14.4V by ~2000 rpm and stay steady. Switch on the headlights - it might drop a little bit but not much. Let the engine idle and see what it reads then. Once charging (the 2000 rpm) it should continue to charge unless the idle speed is very, very low.

Do you check the sender with the wire attached to ground to measure?
The sender is a variable resistor (the resistance changes with temperature). It varies the gauge's connection to ground through the sender's threads into the engine. I do not know the spec's. You'd need to know what the resistance is supposed to be at a few different temperatures and measure it with an ohm meter & thermometer. You can test the gauge & the wiring to the gauge by switching on the ignition, remove the wire from the sender & touch it to ground (bare metal). The gauge needle should go to max. But that doesn't tell you if the sender is working properly or not.
 

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What would be a good reading to conclude that the voltage is low? What should it be? I cleaned the terminal clip
today, and after that my nap got in the way of a test...Do you check the sender with the wire attached to ground to measure?
Chief Bre
I was going to reply but it looks like Eric covered everything well. Good luck.
 
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