I’ve had a problem with my 1998 V70 surging at idle when warm. If I disconnect the IAC it runs fine but idles high. With some troubleshooting it appears the cooling fan is not turning at low speed, it does turn on high speed at about 217F but that’s right where it trips the check engine light. I also have a 1997 850 and the fan turns on low speed at 170F. I have replaced the thermostat and coolant temp sensor. I have swapped a known good relay between cars and the fan still does not turn on at low speed. I have jumpered 12vdc to the fan and it runs fine both low and high speed. Does anyone have an idea why the fan would not turn on at low speed?

 

Hello boys,

I own a 2010 volvo d5 awd, recently I borrowed an obd readers and I monitored thst the coolant temperature is not going higher thsn 60 Celsius even after long time running or the car stationery!! Is this a sign of a failed thermostat?

Best regards to all