Expert: Robert Summers - 5/31/2008

Question
My sons car gets hot,around 220,fan not running,also CO levels are high, it failed local emisions test,cannot get plates,could this be the coolant temp sensor? Where is it located and what might be the parameters,thanks.

Answer
Hi Mitchell... first see if fan relay is working... relay should kick in at around 90C + or - 10 if relay not working change it or find the open in the circut...plug in scan tool and take a reading for temp sensor...see if it matches what it says on the dash or use a infared thermo gauge. if it matches temp sensor is ok... if not replace it there could be 2 temp sensors on that car, one is for the fan control in the rad. the other should be around the TBI opening on the intake...when you go for next emisions test make sure that you change the air and fuel filter change the oil and filter make sure you show up right at the appt time and car is good and hot so the converter is hot making it work properly, also a tank of higher octane fuel helps. oil change being the most important... and if you suspect that plugs are old change them too... hope this helps