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Peculiar Fan Activity

2K views 16 replies 8 participants last post by  GasGuzz 
#1 ·
Greetings. Today, after an oil change I had, for the first time since purchasing my 2012 Outback 2.5i CVT, started the engine with the hood opened; it occurred to me that the radiator fans were on for approximately 10 seconds after startup. The present climate in my area is -20 celsius (-4 farenheight) and the fans seldom spin even in the summer months with the exception of A/C use.

Also, following the start up, the fans pulsed on for a few seconds every few minutes.

Whats the story here?
 
#2 ·
Where do you have your climate-controls set? This may affect the operation of the fans.


Just like the AC compressor which is programmed to engage even in the winter to keep the lubrication circulating.... I would not be surprised if the fans are also designed to run once in awhile to keep them from seizing up.
 
#5 ·
I'm fairly sure that anytime the AC compressor is operation the radiator fans also turn on. When you have your defroster on it uses the compressor to remove some of the moisture to help prevent the inside from fogging up.
Feel free to test this out by turning on full AC and seeing if your radiator fans are spinning.
 
#6 ·
The owner's manual for my '13 3.6R indicates the A/C compressor may not cycle on below 32F. So, I think it's very unlikely to run at -4F. I'll check the cooling fans operation when I start the car tomorrow (below 0F predicted) and report back on behavior. I'll bet the cycling is to keep the fans from seizing from disuse.
 
#12 ·
So it was -4F this morning. The radiator fans did not kick on when I started the car, nor with ANY setting of the climate control system. Although the owners manual does not say specifically that the AC does not turn on below 32F, it does say on page 4-8 that defrost may not work properly. The behavior of the radiator fans in my 3.6R seems to confirm that the AC would not work at -4F (which makes sense), assuming the radiator fans run whenever the AC compressor is on.

"However, if the ambient temperature decreases to approximately 32F, the air conditioner and dehumidification system may not work properly."

So, back to the OP question, I'm not sure why your Outback had the radiator fans run in the circumstances you describe.
 
#14 ·
Was it immediately after the oil change you had? Is it possible they ran the engine up to temp to check for leaks and then shut it off and the engine was hot enough when you started it to turn on the fans? Sometimes the engine can get quite hot when the flow stops after shutoff before it begins to cool down.
 
#15 ·
Floor/windshield setting typically means that a/c is on.... anytime any setting that involves windshield automatically turns the a/c on....sometimes, it doesn't even shows a/c symbol on display - as Brainanator pointed out!
I suggest you check the outside fan when all climate controls are off/disabled. If it still pulsates in this mode, then you have an issue....
 
#16 ·
Further testing has revealed the following:
(1) When the car is started from cold (-10 Celsius) the radiator fans do not turn on when the ventilator is set to any setting, including windshield.

(2) When the car is warm, i.e. following a 40 minute trip, BUT allowed to cool for 10 minutes and restarted again thereafter, the radiator fans spin regardless of the ventilation directionality and fan speed selected.

(3) After an approximately 15 minute trip and NO cooling period, unlike configuration (2), the radiator fans will not turn on regardless of ventilator direction, exactly as in (1), starting from cold.

Is observation (2) normal operation? Do the radiator fans need to operate the dissipate heat to the HVAC core in -5 to -10 degree weather?
 
#17 ·
Yes, (2) is normal. The ECU by engine temp parameters turns on the fan. But then again it may not the next time (after 10 mins.), you’re talking modern day engine management – who else can monitor your engine at 5x per second. Your observations are also only by simple visual sampling.
 
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