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Discussion Starter #1
Hey everybody. Anyone have the answer around at what temp or when does car decide to turn engine fan on? With no AC on, when u shut car down I hear the fan come to a humming stop and other times I hear nothing even though car is warmed up. So I suspect, even though if car is at operating temp, that doesn't mean fan turns on.

Any answers? Thanks!
 

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Happened to me yesterday and the fan stayed on for approximately 5 minutes after shutdown. The car operates at 220 degrees but outdoor temperature here in the New Mexico desert was at 101 degrees yesterday at about 2pm. So not sure how that fan reacts to other elements, outdoor temp, body temp of the car, etc. but I assume internal temp for engine still stays at 220.


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Depends on the temp at shutdown.....Most all modern cars work this way..

220 on your Analog gauge is NOT a real temp reading. It's a smoothed "fake" gauge that will report 220 from actual 180 degrees on up. To see real temps bring up the digital readout..
Here's a scangauge readout Vs in car digital vs fake gauge:

IMG_0058-vi.jpg
 

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220 on your Analog gauge is NOT a real temp reading. It's a smoothed "fake" gauge that will report 220 from actual 180 degrees on up. To see real temps bring up the digital readout..
Does your digital sometimes read above 220 while your analog shows 220? I would like to rely on the analog at least for operating temp since I have my DIC set up to display other important info. I have never seen my analog show above 220 but I am assuming the coolant is being maintained at 220. Bad assumption? If the coolant went to say 240 would the analog show 240?

How "fake" is it? Anybody?
 

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My fan may stay on for a minute or so as well depending on temps outside. Hasn't made it out if the 90's yet.....thank goodness. We'll see what happens as summer kicks in.


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Discussion Starter #6
Does everyone's fan make a turbine hum as it comes to a stop? If I'm in garage or have door open as I shut engine down I can hear that. Normal?
 

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Does your digital sometimes read above 220 while your analog shows 220? I would like to rely on the analog at least for operating temp since I have my DIC set up to display other important info. I have never seen my analog show above 220 but I am assuming the coolant is being maintained at 220. Bad assumption? If the coolant went to say 240 would the analog show 240?

How "fake" is it? Anybody?

Yeah...Bad assumption. I don't know at what temp it takes to move the gauge off 220, but I would assume the skew is on the high end as well as the low.
My VW, which have a smoothed gauge readout of 190 degrees reads that same number anywhere from 160 to 215....
 

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I think I'll refrain from posting a comment here since I was branded a hater on another forum on this topic. ;)


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So not sure how that fan reacts to other elements, outdoor temp, body temp of the car, etc. but I assume internal temp for engine still stays at 220.
Well...Not really. Temps will definitely go above 220 depending on conditions. I don't know the fan kick-on setpoint but it is over 220...Determined most likely by the engine temp sensor....Fast idle your car in the drive on a hot day and observe the digital readout.
You'll see at what temp the fan actuates once it hits the setpoint.
 

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I think I'll refrain from posting a comment here since I was branded a hater on another forum on this topic. ;)


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Hater? I won't hate you if you can give some insight to my Q in post#4 on this thread.
 

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Better to understand how the fan is commanded by the PCM by seeing how PCM is programmed for fan rotation and run on.

There is safety logic that if the powertrain temps are too high when engine is turned off that a "run on" function commands the fan to stay running until the values set in PCM calibration are meet. Either by temp and/or by timer in seconds.

Looking at the PCM calibration fan table and constants in a C7 below you see the GM setting is not even commanding the fan any rotation until greater then 218 F water deg
Above that temp the PCM commands a 14.9% rotation and then higher percentage of how much rotation the fan will be commanded to rotate as water temp increases.

View attachment 9336
 

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Yeah...Bad assumption. I don't know at what temp it takes to move the gauge off 220, but I would assume the skew is on the high end as well as the low.
My VW, which have a smoothed gauge readout of 190 degrees reads that same number anywhere from 160 to 215....
"Smoothed" is putting it diplomatically. Its more like non-responsive! To my mind, not showing the difference between 160 to 215 makes the analog gauge about as useful as an idiot light...maybe even less useful. An idiot light at least gets ones attention...usually!
 

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"Smoothed" is putting it diplomatically. Its more like non-responsive! To my mind, not showing the difference between 160 to 215 makes the analog gauge about as useful as an idiot light...maybe even less useful. An idiot light at least gets ones attention...usually!
The two gauges may be measuring two different things using two different sensors. Note that they are identified by different icons. Maybe the digital engine icon is measuring the block temp or "engine temp sensor" as Modshack refers to it in post #9. Never seen that icon used to represent the coolant temp. Modshack, what about that?

My analog coolant gauge reads the gradual rise in temp as the car warms up. It registers 160, 180 etc. as it rises to the 220 warmed up temp. I have seen nothing here that convinces me the analog coolant gauge is "fake" or anything other than what it is represented to be. See other thread on this forum covering this same topic.
 
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