My wife has an 02 vovlo s40 and last time i drove it, shut it off, i noticed the engine fan remained running for a while. Never heard that before... now druing this -30 degree weather i got it running and noticed right off of enginer start, the temp gauge in the car was already half way (no engine block heater on this car)... not long after the temp gauge was maxed out... coolant levels are ok and what not... what could cause the temp gauge to be incorrect... when it maxes out is that telling the fan to run?? any one experiance this???

 

Think logical.
1.maybe the temperature sender is faulty,unlikely the guage is the problem.
2.Are you sure coolant is correct level.
3.The thermostat will need renewing if you change the temperature sender as it is located near it and just makes sense do to do it while you have it apart.
4.Water pumps generally are changed when the timing belt is renewed on these models.
5.On the passenger side under the car in front of the front wheel there is a little relay that volvo mounted upside down and fills with water and rusts out that holds the engine fan on,get familiar with it.

6.When you turn the engine off on a hot day the fan always runs on until engine is cooled to correct temperature,this is designed by volvo,generally a couple of mins run on then shuts off automatically.

Ok that should get you thinking,go find the problem.