Is your engine fan running louder than you remember that it used to? Are you having intermittent A/C cooling problems? It could be your engine coolant level!

I know this sounds boneheadedly simple, but I bet it is an easy thing to overlook. I bought my Crossfire three months ago from a very reputable dealer. They gave me the spiel that they had completely gone over the car and checked all fluids and changed the oil with fresh new synthetic. I checked the oil, and it was fresh, so I foolishly assumed everything else was up to par as well.
After driving my car for a while, I noticed the engine fan often ran pretty loud, but not ever having driven a Crossfire before, I though it was normal since the temperature gauge didn't show a high reading. Then I began to encounter an occasional instance of the A/C not cooling properly.
To get to the point, it was simply a matter of low engine coolant - a GALLON to be exact. I feel stupid, but a the same time, my Crossfire is running beautifully, the engine fan is barely audible, even in the July Texas summer heat, and my A/C is delightfully chilly.

 

Why would the fan sound differently with a low coolant level?

 

i would guess that the coolant temp sensor it too hot with the lack of flow, so it's telling the fan to fun faster to cool it down.

 

With insufficient coolant, the fan spins faster to draw more air over the radiator. Higher RPM's equate to a much louder fan.

 

Good to know, most electric cooling fans are one speed. Having a variable speed fan is new to me. I am also thinking that on many cars the loss of coolant inhibits the fan as the temperature never gets high enough to trigger the on setpoint due to lack of coolant around the sensor.

 

I can't make sense of how this would have any effect on the A/C. The faster the fan runs, the cooler the A/C will be.

I even use my "instant cool button" when stopped in traffic to keep the A/C cool. (I put a button on the console to put the FCM into emergency mode, I don't use it much since I had the -10C mod done, which makes the fan run starting at 16 degrees lower than factory. But when I'm in stopped traffic on a hot day, I still use it to keep the A/C cold.)

 

I'm no mechanic, but my assumption is that if the temperature levels under the hood are too high, it will not allow the condenser to remove enough heat to allow the system to cool properly. The condenser is in front of the radiator, but the compressor and the dehydrator are in the engine compartment. If the engine coolant in the radiator is excessively hot as well, I think there simply was not enough of a temperature differential to allow the A/C system to remove the heat from the freon. The fact that the system would begin to cool again after I reached highway speeds validates this issue. (My mechanic thoroughly checked the A/C system - the system was fully charged.) I assumed it was possibly a low freon level, which would have shown up as ice on the high pressure line - when I inspected the lines, they were all very hot to the touch.
Thankfully, the variable speed engine fan is large enough to compensate for such an egregious low coolant level and keep the engine itself from overheating.

I think that is an important point here - the coolant systems in our cars are robust enough to handle even such a large problem as significant coolant loss. I drove my car all over the place in the Texas summer heat and it managed to compensate for the low coolant with the variable speed cooling fan.

 

I'm thinking that maybe you were hearing water pump cavitation due to low coolant. Fan should sound the same regardless of coolant level imo. I think the fan comes on automatically when the AC is switched on to cool the condensor.

 

Might be time to get a new coolant level sensor too

 

You may be right about that. Looking over the materials I got when I purchased the car, they had changed the overflow tank - there's my source of missing coolant. Since I did not get a low coolant light, I am going to check the sensor.

Regarding the fan speed - I can tell you without a doubt that the fan speed on MY car is variable. It may take unusually high engine temperatures to raise the speed - let's hope that is something that most owners have just not experienced.