2000 V40 Temp Gauge Erratic and Engine Surging

The new temp. sensor (ECT) did the trick – cured all of the temp. gauge problems. My only current problem is a P0128 OBD check engine code. My research suggests that the problem is probably an aging thermostat. I’ll ignore it for awhile and see what happens.

2000 V40 Temp Gauge Erratic and Engine Surging

3 Replies to “2000 V40 Temp Gauge Erratic and Engine Surging”

  1. 2000 US model V40 turbo 1.9 with 78k.

    Erratic temp gauge, fan cycle one comes on at 3/4 and fan cycle 2 kicks in when close to red and stays there.

    Fan cycle 1 comes on when car is turned off for 6-8 min. This can drain battery quickly.

    Disconnect the temp sensor. This stops the cycle 2 fan, but not the cycle 1 fan.
    I would disconnect the negative lead to battery after you get home if you cannot repair it for a few days.

    Took original temp sensor off. Put in cheap $15 replacement. Mistake! Same symptoms started about a few days after.

    Could the cheap part fail that quickly? YES!!

    Went to dealer. Paid $55 for part.
    All symptoms have cleared for now. Apparently they break quiet often and aftermarket on this part is not recommended.
    Make sure you have blue silicon based coolant in the car as this can ruin the sensor.
    Pentofrost NF or Volvo coolant.

    Its a good idea to replace the 90degree thermostat and seal if its been more than a couple of years.

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