QuestionQUESTION: hello. Ive a 1998 Nissan maxima. Ive always noticed that it seemed a bit hot when in the city driving.
Now,,,when I drive about 30 minutes,at 50mph,,temp gage rises fast,& overheats.
Was in traffic last week and noticed needle a bit up,took to mechanics,they put new relay switch,and fixed broken wire to get fan running.
thought everything was fine,,set out driving,,,glanced at needle,and it was going to top of gage,,,pinned & overheated again. Got back to mechanics,,they ran it for hour,drove local and no over heat again. Im scared to go on any travel,or sit in city traffic. What can it be?
ANSWER: Hi Karen -
Assuming that the fan is working properly, these are other things you can check -
Thermostat
Radiator clogged/fins corroded
Temperature sending unit
Also notice when your A/C is on, does the car run cooler? The A/C switch, when on is supposed to kick the fans on. If the A/C is not on, then the fans will go on when the car reaches a certain temp. If this is not happening, then check the sending unit.
Hope this helps -
aloha
calvin
---------- FOLLOW-UP ----------
QUESTION: WELL,WE SEEM TO BELIEVE ITS THE WATER PUMP. HAVING THAT AS A GUARANTEE ,THAT AT HIGH SPEED ,,,NOT COOLING.
WHY DOES EVERYTHING POINT TO THERMOSTAT>/?
iM REPLACING THAT TOO. WHAT IS THE SENDING UNIT,,I DONT NEED 1 MORE ELEMENT OF QUESTION.
AnswerHi Karen -
Sorry. I was merely trying to explore all components of failure to the cooling system as there are many. The sending unit is the device that senses the temperature of the coolant and if too hot, sends a signal to the relay to start the radiator fans.
The thermostat is the most common item that fails, so definitely should be checked first.
Personally I do not think it is the water pump. If the mechanics ran it for an hour, and test drove it with no overheat, there is no way that the water pump has failed. The water pump is a very expensive repair so be careful of that decision.
Aloha
Calvin
