Engine Cooling problem
2004 Infiniti I35 6 cyl Front Wheel Drive Automatic 109000 miles
My I35 lately seems to be running alittle hot while A/C is on in normal traffic according to the gauge on the dash. If I turn off the A/C and just run the Fan the temp drops slowly. If I turn on the heat the temp will go down to the normal range. If I return to A/C the temp will rise. Mind you that the temp is not rising to the overheat stage, just that the cooling fans are running pretty hard. What do you think is the problem?
What you are describing sounds normal.
By turning on the heat, the blower acts as an additional fan on the coolant and should lower the temp.
The a/c when turned on will allow the second fan to run to help reduce the extra heat produced.
If it is a little hotter than normal it may be a radiator that is partially restricted or restriction elsewhere. A sticky thermostat may also cause a abnormal temp reading. I would try a coolant flush if it is due. Check the fins on the rad for restriction of air also.