Why does my low coolant light come on when its not low? - Ford Mustang Forums : Corral.net Mustang Forum
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post #1 of 6 Old 04-11-2003, 04:03 PM Thread Starter
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Thumbs down Why does my low coolant light come on when its not low?

The low coolant light has been coming on when the car is just started cold and it will stay on till the car heats up and i turn it off then back on. I checked the radiator and overflow bottle and both are filled to the point were they need to be...The thermostat is working correctly as well....dont know what could be wrong other then the sensor is on its way out....Isnt it located in the engine housing? not sure...thanks in advance

'13 GT
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post #2 of 6 Old 04-11-2003, 04:24 PM
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Their is a sensor located in the bottle.. its attached to the cap housing... sometimes it gets all gummied up, and gives a false reading.... trying pulling it out, and cleaning it up... might be a free fix..

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post #3 of 6 Old 04-11-2003, 04:28 PM
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hey... no help here but I have just recently been fighting the same issue: low coolant on cold starts w/ a full reservoir, then the light goes out as soon as I key off/key on when warm. I havent given much thought to it yet, I have bigger fish to fry, but I suspect it would be either the sensor in the overflow tank or possibly the computer, seeing as how the light stays on until key off. let me know if you find a solution!
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post #4 of 6 Old 04-11-2003, 04:31 PM
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your coolant level sensor is in the overflow tank. I had the same problem when my coolant was cold, its will register a lower amount, once it heats up, it expands and thus the light cuts off.

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post #5 of 6 Old 04-11-2003, 05:19 PM
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The sensor needs a small amount of conductivity between the contacts to "see" the water level. If you added pure water it takes a while for enough mineral/oxide content from the block and such to dissolve and increase the conductivity.

That's one culprit, and the contacts do get gunked up which is an insulator of sorts.
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post #6 of 6 Old 04-12-2003, 02:11 PM
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Mine did that. Replugged it and it worked for awhile but came back so I unplugged it to keep the light off.

As long as you monitor your water level I would think you would be OK. I haven't gotten to a junkyard or checked online to see price. Looks like $47 for the sensor at Fordpartsonline.com but some places are a bit cheaper. Guess I'll wait.

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