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Old 22nd March 2017, 20:10   #1
AustinMaxi
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Default high speed fan on and odd temperature reading on hot engine

After about an hours driving home from work I stopped the car for 3 or 4 minutes, waiting to pick up one of the kids.

On restarting the engine and the high speed fan comes on and the temperature gauge sits in the 6 o'clock position over the blue spot. I stopped the car after 100 yards and checked the engine but no obvious sign of anything wrong.

So I restart the car again and everything is back to normal, no fan and temperature gauge at 9 o'clock.

Is there any explanation for what caused the odd behavoir?
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Old 22nd March 2017, 20:18   #2
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Could be a bad connection to the gauge. Signal could have been right to fan. Most likely computer glitch.
Check water when cold, to be safe.
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Old 22nd March 2017, 22:46   #3
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Quote:
Originally Posted by AustinMaxi View Post
... the high speed fan comes on and the temperature gauge sits in the 6 o'clock position over the blue spot.
Loss of a valid signal from the coolant temperature sensor Martin. The fan runs at high speed as a precautionary measure since the ECU doesn't know the true coolant temperature. Check your wiring to begin with.

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Old 29th June 2017, 09:19   #4
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This incident of the temperature gauge dropping to zero and the high speed fan continuously operating happened again this morning, presumably due to the wet weather and surface water penetration into the electrics somewhere. Fortunately I was ¼ mile from work when it happened and kept on going.

If it happens going home, can I drive the car home without damaging the engine?
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Old 29th June 2017, 12:09   #5
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I have just driven the car at lunch time but the high speed fan came on after 50 yards. Temp gauge sat next to the blue dot and not moving.

I was hoping the heat of the engine this morning may have dried it out.

Can I drive the car home this evening like this?
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Old 29th June 2017, 12:23   #6
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Pull the sensor connector off and check/clean as necessary. Clean the connector pins on the sensor. Apply some WD40 type agent on the pins/plug before refitting. If gauge still remains at 'blue' with the high speed fan running, the wiring from sensor to the ECU is suspect. This is the locationof the sensor.



Driving with the high speed fan running is not in itself a problem other than the noise factor. The running temperature should remain above 88-89C (assuming the thermostat is OK), so no implications for the engine. The fan shouldn't be run continuously at high speed for extended periods, so it depends on the duration of the drive home. How long's a piece of string?

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Old 29th June 2017, 14:34   #7
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Thank you so much, I have followed those steps and taken the car for a short drive and it seems back to normal.
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