Auxiliary fan is a two speed fan. If you notice it has 4 wires connected to it.

It'll activate in stages. 50% and 100%

Regardless of ambient temperatures it's all ECU controlled when the coolant temperature reaches those levels stated above.

It also goes based on a/c condenser pressure when the a/c is activated. Then many other variables play a role.

On the consult information sheet, it states that at certain MPH when A/C is on the fan will be kicked on and above those MPH it'll be turned off. But that's irrelevant to your current condition.


50% = half power
100% = full power

 

I want to thank everyone for their valued comments here. My car is no longer overheating, but I found out the problem was something I previously hadn’t considered.

The day after my last post, I met with one of my valued acquaintances, a Nissan Master mechanic. When I suggested what I (we) thought might be the issue, he quickly told me that I was over-thinking things and stated that he was 90% sure that I’ve run into a problem that he’s seen innumerable times with other cars, especially Nissans- the radiator was clogged!

Since the rad and the AC condenser are so closely sandwiched together, material that gets through the condenser builds up and clogs airflow to the rad and has nowhere else to go. He recently worked on a Titan, an Altima, and a G35 and showed me one rad that had an encrusted mat of material over its surface!

I went home and went to work on this, and without total removal of the rad, flushed what I could off the front of the rad and my temps dropped to nearly normal on the first drive following! No more high temps, even with the AC on!

This past W/E I fabricated a flushing wand (only need a ½” to 1” clearance and sprays at 90 degrees) so I could do a more thorough flush. I sprayed the AC condenser and the rad with foaming condenser cleaner and let it soak for a few minutes and flushed virtually all of the crap out from the rad and condenser.

I’m pleased to say that my temps are within a degree or 2 of the table posted by Eric, the AC is blowing ice cold air, and it's no longer overheating!

So I thought this may something that others may find useful as well!

 

BTW, does anyone know what the AC Economy setting actually does as opposed to just AC?

I've always wondered and not sure if I've ever noticed much difference.

 

So finally does the cooling fan run as soon as the A/C is switched on?

 

When you mean flushed what you could off the front of the rad you mean coolant flush or another type of flush?

 

No. I think it's as Eric said:

 

I did do a coolant flush as well, but what I meant previously and what made virtually all the difference was flushing the fins of the radiator as the grunge that built up, especially between the AC condensor and the rad, was blocking a significant amount of airflow. I also flushed from behind the AC condensor to ensure maximum airflow passing to the rad.

 

When my a/c is on, the condenser a/c fan doesn't turn on so it makes my thermostat go way up the normal. But whenever the a/c is off it stays in the middle... any possibilities?

 

BTW is it normal that the coolant is never at the same level? Sometimes I see none in the bar, sometimes it is at MAX...

 

None at the bar? Please clarify.


Usually while the engine is on and temperatures are operating normal you will see the reservoir tank have a bit more fluid than "normal".... this is normal as long at it is not overfilling and pouring out of the container.

When you wake up in the morning you will notice it may be at Minimum. Again, this is normal as fluid contracts and expands with heat.

Also you have to remember the radiator cap handles these functions.

 

from what i heard(if i find the post ill link it) if its 70 degrees outside and 80 in your car and you set your AC to 60 w/ auto-econ and you hit auto econ, it will use the outside air to cool your car to 70 and then kick in teh AC compressor, and keep it stable like that. that way you're not unneccesairly losing that precious 10-30hp

 

Sounds sort of like what mine was doing. The condenser fan should go on if the dash temp gauge goes above normal however.

The dash temperature gauge is not very useful in trying to accurately figure out what is actually happening however. Fortunately, I have a ScanGauge II installed in my car which shows me the actual temperatures. The dash gauge will show normal (middle) from about 70° C (158°F) to almost 100°C (212°F) I believe. It pretty well stays there within that range, but rises fairly quickly above that when your engine is already overheating and when it reaches the ‘H’ mark at about 125°C (260°F), you could be doing some damage to your engine! You should see if you can hook up an OBD II scannr that will show you the actual temps.

If your car is over 5 or 6 years old, I’d say it's possible your issue may be the same as mine was, ie. that the fins on the rad (between the rad and the condenser are clogged.

Otherwise, it may be likely that it’s one of the other issues suggested here including the fan clutch.

I’d try flushing the rad fins as a first step since that is what made a tremendous difference for me.

 

Hmmm. Sort of makes sense, but I thought I noticed the compressor kick in as soon as the button is pushed regardless of temperatures. I'll have to take more notice next time.

If you could find the link, it'd be appreciated.

TIA

 

If you're a fan clutch engine setup... and running 212... you need to replace the fan clutch. It should never reach past 205 unless you are tracking and not giving the engine cool down laps/periods.

 

ok, not the original link i was looking for but this one should do! look at post #9

https://g35driver.com/forums/g-spot/...-heater-c.html