Volvo 850 radiator fan.
 

Hello, first Merry Christmas to all.

I recently replaced the thermostat on my Volvo 850 1997 non turbo (was broken) and replaced as well the coolant temperature sensor.
I noticed recently that as soon as the temperature of the engine (gauge on dash) reaches half way (and it always stays there afterwards while driving), the electrical radiator fan kicks in even if I just drove a few miles.... I don't recall the car doing this before that early and especially in winter. When I turn the ignition off, the fan keeps running for minutes... the car never did this before, fan would usually switch off as engine was shut off...
Any idea if this is normal? I recently unplugged the battery and could this be linked to the ECU reset or maybe my cooling fan relay has gone bad?
Any idea or suggestions would be awesome! Thanks!

If the thermostat is working properly the cooling fan can come on even if the gauge is in it's "normal" 3 O clock position. If it's coming on after it's warmed up that would likely be normal and the only way to really check it would be to tape a thermometer to the upper hose or hook up an OBD II live data reader if you have OBDII and actually "see" the temperature it's coming on at.

As for the running after the ignition is off. ?? I don't know. I'm pretty sure mine shuts down with the ignition switch but I've never paid attention to it.

well if it did stay on you would definitely hear it... on mine it stays on low speed mode and it's quite loud especially in an enclosed area like a garage.

As for the running after the ignition is off. ?? I don't know. I'm pretty sure mine shuts down with the ignition switch but I've never paid attention to it.[/QUOTE]

Our S70 does that but when the NEW coolant temp sensor went bad, it would run our fan all the time. The fan should come on when the motor reaches 216° and go back off at about 205°. When the car is turned off the fan may run for up to 5 minutes.

My '95 fan does not run if the car is off and I could not find anything in the owner's manual about it running after the car is off.

Many vehicles fans run after shut down. When the motor is off it stops circulating the coolant and the sensor reads that stagnant temperture sending a signal to the fan to cool the radiator. Maybe the new sensor is working properly now which is why it didn't do that before.

Trace (chk/test) each component in the diagram to see who is causing a seasonal joke.

JPN

The issue was a bad connection to the temperature sensor, that would trigger the fan to start no matter what the coolant temperature was.