My 300 m has been running fine but one day ran hot all of a sudden and the temperature gauge started rising past half and even more but turned it off. Won't start from being hot but let cool and tried once more, it stared but check engine light was on and no hot air. Had it tested and radiator fan high and low relays tested bad, so I put new ones in. Still ran hot, gauge stayed at half and sometimes began to rise even more. So I did a compression test on all 6 cylinders and they all held at 180 pounds. Then I remove the thermostat and tested in boiling water about 6 times at 212 degrees fahrenheit seemed to open up just fine. And put back together. Same problem as before. I have a new radiator and hoses new thermostat fans turn on and seem to work just fine. They turn on at about below the half mark on the temperature gauge. I even took the top radiator hose off and with the car running put water in the hose and took it just fine. Why is my car still over heating and running hot? PLEASE HELP ME!
Sunday, April 22nd, 2012 AT 11:19 PM