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Cooling issues

1281 Views 3 Replies 1 Participant Last post by  **DONOTDELETE**
I recently did preventive maintenance on my '94 Explorer V6 including draining and replacing the coolant, replaced hoses and thermostat and even removed the heater core and thoroughly flushed that as well. I've noticed now that the temp gauge will "spike" occasionally when driving. It will go from the "N" position and jump up to "M" and then back down in a matter of seconds. What could cause this? Air in the system? This didn't happen before I did the coolant work and was wondering if I disturbed anything.

Thanks in advance!
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i always thought temp gauges had h and c or numbers.
is it a mexican vehicle with (n)ada and (m)ucho caliente?

1. air pockets could cause that but generally work their way out of the system. you could have it vacuum filled if you determined that to be the cause.

2. in changing parts, you couldve dislodged some foreign particles which circulated through your cooling system and settled in to restrict coolant flow.

3. its an electrical sending unit. is it possible the wiring developed a short or is touching something which could effect the reading?
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Sounds like your cooling sensor is going bad. To find out if thats the problem, take the radiator cap off and start your truck. Put a Thermometer in the radiator and check to see if its giving you the same reading the Temp gauge is. If its the same than its your cooling sensor.
To be blunt, the stock gauges are trash. What is "Hot" or "Cold"??? To have any idea, you need to install an aftermarket gauge with actual numbers on it.

What you are seeing most commonly has absolutely nothing to do with the temp of the coolant, but more often than not is a voltage regulator for the gauge cluster on the fritz.

On a side note, don't trust the Oil Pressure gauge either. It is just a switch set at 3-5lbs of pressure. Anything above 5 lbs and the gauge reads normal, anything under and it reads no pressure.
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