Engine water temperature
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OneForTheRoad
MB Enthusiast
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- 2019 Glc coupe 350d was 2017 e350 c207 .. +65 ford kuga 2.0 cdi zetec awd..
I've owned a few mercs now and can't ever remember the fan kicking in. All dirty diesels though.
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- Feb 8, 2007
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- Portsmouth, Hampshire.
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- E55K SL500 E250X2 Smart44 Brabus Track car E450Cabriolet X350 Pick up
Full yield is 100degreesC.
Most fans tick over at 80-90 degrees. The fan is also used for the AC too so its not necessarily engine temp dependent.
Most fans tick over at 80-90 degrees. The fan is also used for the AC too so its not necessarily engine temp dependent.
mine appears to be cutting in at 92 degrees.the problem is its just started doing this the last few weeks.at the moment we have very cold weather.it never did it in the summer or autumn when the ambient temp was higher.what i am afraid off is when the weather warms up the fans might be running nearly all the time leading to them to break down prematurely.
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- Portsmouth, Hampshire.
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- E55K SL500 E250X2 Smart44 Brabus Track car E450Cabriolet X350 Pick up
Cutting in so you can hear it? Is the fan going fast?
if i stop at traffic,or park the car up and switch off engine the fan cuts in within about 15 secs,it runs at the high speed for a few minutes,then a few minutes at the slower speed.
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- Portsmouth, Hampshire.
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- E55K SL500 E250X2 Smart44 Brabus Track car E450Cabriolet X350 Pick up
You could have a faulty AC pressure sensor. Id get it plugged in to check fault codes and the AC pressure sensor actual value just to be sure.
MrGreedy
MB Enthusiast
Mercs typically run (have thermostat operation set) at 87-90 degrees C depending on model/age. Slow speed fan at 92 degrees would be normal.
If the fan is kicking in at this time of the year whilst very cold outside, you are either constantly interrupting diesel DPF regen (that doesn't apply in your C43 case) or you have a fault somewhere.
After fault code checking, the best way to look at this is with diagnostics looking at live data whilst the car is running up to temperature. Looking for wayward temperature readings or the AC system for faults or unusual reading as BlackC55 suggests.
Most likely culprits are AC temp/pressure sensors. Water temperature sensors. Thermostat.
I have known fan control circuitry to become faulty on much older cars after eventual water ingress, but this gave erratic fan behaviour and the water of course didn't get over temp, because the thermostat was doing it's job properly.
If the fan is kicking in at this time of the year whilst very cold outside, you are either constantly interrupting diesel DPF regen (that doesn't apply in your C43 case) or you have a fault somewhere.
After fault code checking, the best way to look at this is with diagnostics looking at live data whilst the car is running up to temperature. Looking for wayward temperature readings or the AC system for faults or unusual reading as BlackC55 suggests.
Most likely culprits are AC temp/pressure sensors. Water temperature sensors. Thermostat.
I have known fan control circuitry to become faulty on much older cars after eventual water ingress, but this gave erratic fan behaviour and the water of course didn't get over temp, because the thermostat was doing it's job properly.
yes,coolant level fine,its never used a drop.
