Hello, I have a 2006 Maxima with only 57K miles.

I have a problem where sometimes when sitting in stop and go traffic after 5-10 minutes, my temperature gauge sudden rises.

If I turn off my AC, the temperature gauge rapidly returns to a normal range.

I have read the many posts on the cooling fans here and on various sites and tried to do some diagnosis.

Here is what I have done so far.

1) Flushed the radiator using Prestone flush. I didn't see any visual corrosion in the radiator, but I guess it could be not visable
2) Verified that both fans turn on when the AC is turned on.
3) Visually check the fan fuses
4) Tested the temperature sending unit.
5) Ran the Nissan IPDM self test and verified that both fans turned on an cycled through the various speeds.

Here is a question that I can't seem to get a straight answer for: When do the fan(s) turn on WITHOUT the AC on? I have left the car sit for long periods of time to let the car get quite warm and I don't ever see the fan(s) turn on when the AC is NOT on.

I then switched positions of all three fan relays and didn't see any change of fan behavior.

I thought maybe I had a intermittent fan, but now I don't know.

Any thoughts would be greatly appreciated.

Thanks,
Bob

 

The fans should turn on from about 90 degrees Celsius. Maybe your engine coolant temperature sensor is malfunctioning.

 

My fans only come on when the AC is on as well. Other than that, they typically do not turn on.

If you have not done so yet, then change out the radiator capo with a new one (when engine is cold). I change mine every 5 years. They cost about $13-$15.

 

Thanks for the reply.

I know the engine is "up to temperature" but maybe it isn't reaching 90 C. I measure the temperature sensor resistance when the engine was hot and it was around 275 ohms. When cold, it was over 2700 ohms so it appears to be working.

 

Thanks

I haven't replaced the cap yet