IROCtheZ28

I changed my hoses, thermostat and coolant due to the recent extreme cold weather here and for maintenance reasons. Fired it up, checked for leaks, 60 mile leisurely cruise. So far, so good. No leaks or other problems.

But...everytime my 305 fires up and idles, the left electric fan spins only while the right does not. The right fan does spin with a gentle push by hand though. The temp gauge is floating normally at a comfortable reading below the 220 degree mark.

My question is does the computer switch on one fan at a time or two under general use?

If the right fan is found faulty, is there the potential for hurting the engine? I ask this because since I purchased the car I absolutely had no overheat or cooling issues at all from day one therefore I'm assuming one fan is doing a fine job but I rather hear and watch two fans spin for assurance.

I also want to know if any of you have any trick aftermarket electric fan setups with the name of the manufacturer also. My stock dual electric fan assembly is showing some minute cracks due to age.

LesPaulGoth

I thought the second one turned on in severe heating cases, I could be wrong though, only one of my fans is left so I wouldnt know lol. You can't really test the second fan though because where you are it's gonna be too cold unless you let on it in park for 20 minutes but you dont wanna do that lol. Just live with it and if you start to notice overheating problems in the summertime, then start to get concerned. Like I said, I only have one fan, and I'm in NJ and I never overheat, then again, I have a manual switch and I just constantly run it.

As far as aftermarket setups, I never looked into it but from what I hear, they are pricey.

raul.garcia

During high-way driving the air circulating through the engine compartment is enough to cool the engine and the fan is hardly used.

The primary should be on by the time it gets to 200°F (as reported by the CTS, not the engine temp gage) if the ECM is programmed for a stock thermostat which should be around 195°F, but this also depends on the Coolant Temperature Sensor (CTS) that's providing the temp signal to the ECM. a faulty CTS signal will turn the fan on too soon, or too late, or set a SES DTC (14, or 15 I think.)
Putting the ECM in Diagnostic mode should also turn on the primary fan.

The Secondary is called a Heavy-Duty Cooling fan.
The secondary fan is controlled by a single wire (mine is gray) High-Temp Switch Sensor(238°F sensor in the passenger side head,) and the A/C High-Pressure Fan Switch because they're in parallel with each other.
The Secondary Fan connector is identical to the knock sensor on the same side, but in the block.
The A/C high perssure fan switch, or the secondary fan turning on signal the ECM informing it of the extra load on the engine.

The positive side of the secondary fan relay coil is connected to a "Hot At All Times " source, grounding the High-Temp sensor connector (negative side of the relay coil) to ground will cause the secondary fan to turn on.

If you want to use a manual switch put it on the negative side of the fan relay coil(s) through another relay powered by a KeyOn fuse box source that way you won't have to worry about forgetting to turn the switch off, but be warned the fan(s) won't last long with full time service.