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-   -   Condenser fan really noisy after turn off the car... (http://forum.e46fanatics.com/showthread.php?t=937838)

vinko2000 08-09-2012 04:59 PM

Condenser fan really noisy after turn off the car...
As the title says, the Condenser Fan gets really noisy for about 5 seconds after I turn the car off, like the speed goes up considerably.
Now the facts, the condenser was replaced after a accident on January 2011 when a was living in Seattle WA, it was a used one, I never use the A/C in Seattle, then I moved here to Nashville, last December, and when I try to use the A/C it didn't work, turns out the Condenser had a big leak, it was "repaired" with J-B WELD by a friend, but somehow the A/C wasn't working properly, even when the tester said that it was full of "Freon", the air came just a little bit colder, I took it to "The Car People" in Downtown Nashville (they repair my transmission a few months ago, good job), now they replace the Condenser and the Outside Ambient Temp Sensor ($800), now the A/C works great but I have the problem with the fan, I took the car back to them, but they said that the noise is normal, in the shop maybe the noise is not too loud because all the sound surrounded, but when I go to work for example and I park in the Mall parking lot, the people around me look at me because the noise in my car, really really loud.
Any ideas what this is happening?, I tried to find something in this forum, but nothing similar, I want to take the car back so they can check this but I wanna do it with some information, so they can't tell me again that is normal. Thanks a lot guys.

klax 08-10-2012 01:13 PM

Your fan shouldn't make any strange noises. How long does the noise last - as long as the fan is running? Is your car an automatic transmission?

vinko2000 08-10-2012 04:45 PM

The noise last for about 4-5 seconds; when the car is running, the fan makes a normal sound (as normal as any fan, like the radiator fan), two seconds after I turn the car off is when the fan start spinning really really fast and makes the loud noise, imagine a living room's fan that for 5 second you can increase the speed about five times over the maximum, that kind of sound. When I said that people turns their head, I'm not exaggerating, I guess they are wondering where the noise came from... By the way, the Condenser fan just turn on when the A/C is on, but if the A/C is off and I turn the car off, the Condenser fan start spinning fast and makes the noise anyways after the car is off for the same 4-5 seconds.
And my car has an automatic transmission.
Thanks klax...

mrgv255 12-08-2015 06:43 PM

Hi. Did you ever figure out what was causing this? Same problem here. Thanks!

hirot 12-09-2015 05:30 AM

As you have an automatic you should have two fans an electric one in front of the radiator, called an axillary fan and a mechanical one attached to the front of the engine. Both are for cooling the engine. Manual cars only have one electric fan between the engine and the radiator.
Ordinarily when the car is moving it is cooled by the manual fan, however, when the car starts to need to be really cooled the electric fan comes on. This may be because the ambient temperature is high, the car is going too slowly, working hard etc.
So it could be that the electric fan is only coming on when you stop the car and the heat soaks into the thermostat which turns on the fan for a few seconds. If the electric fan is noisy it probably isn't well.
This was happening to mine and it turned out that the mechanical fan wasn't working properly, it was running much too slowly.
I removed the mechanical fan and the auxiliary fan, as it was 12 years old and replaced them with the manual set up. The car appears to be much happier.

mrgv255 12-09-2015 10:01 AM

Thanks for the reply and the idea to check the mech fan! We've tried just about everything down here including replacing the thermostat, water pump, and 5 or 6 used aux fans I could get my hands on but nothing has changed...

Specifically this is the problem I'm having and it's with the AUX fan: The aux fan seems to slow down and speed up as per normal operating conditions when the car is on.. The problem is that after I turn off the car a couple seconds later the aux fan speeds up to sound like a jet about to take off at full throttle for 5 to 10 seconds (which is incredibly uncomfortable and embarrassing!). I have found no way to fix this and unfortunately I don't remember exactly when or why it started doing this. Since everything seems to work as expected except when I've just turned off the car, I don't know if I should check some sensors or something else...

Any ideas? In the worst case, I'm hoping to be able to get some info to hack up some small circuit with a gate or something like that on the incoming electricity to the fan so that the input to it is cut off when the car is switched off!? Will try anything, thanks for the help!

hirot 12-09-2015 10:21 AM

Not sure why the fan should appear to speed up but if it sounds like tractor then it probably isn't well. Maybe the bearings are going.
If you can easily spin the mechanical fan when the engine is warm (engine off) then it has probably leaked fluid and can't spin properly. The Mechanical fan is basically full of oil which when cold allows the fan to spin slowly and when hot locks the fan so that it spins in order to cool the engine. Another way I saw to test the mechanical fan is to very carefully hold a piece of thin paper to it when the engine is warm and it is spinning. If when you touch the paper to it the fan noticeably slows down then its bust....but be careful/gentle as you don't want to loose a finger/eye or bust the fan.
If you are brave then if both fans are shot then its a cheap fix to remove both fans and just fit the manual puller fan which should theoretically be more efficient and works out a lot cheaper. It just slots in and uses the same electric plug as the AUX fan.

mrgv255 12-10-2015 02:52 PM

Thanks again for replying. We tested the fans as you suggested and everything seemed to be operating well (along with everything else checked) but for some reason the aux fan kept spinning up at max after turning off the car for a few seconds. I got sick of this and took it to an electrician who liked my idea of installing some switch on the input to the fan that will cut off as soon as the car is off (no idea why the fan relay of all tested fans didn't do this already). He called to say he got it working, but I will post back if anything is wrong or if I get any problems with temperatures after I drive it around a few days. Seems like a straightforward hack that should do the job. If you think this is a horrible idea for some reason, let me know.

gwhitten 12-10-2015 03:46 PM

I have noticed with my OBDIIFusion, that the engine coolant temperature as monitored by the temperature sensor located beneath the intake manifold on the engine near the firewall rises after engine shutdown. I'm assuming that this is caused by the heat remaining in the engine block which is no longer being removed by the circulating water. In other words, when the water pump is circulating the coolant, the cool water from the radiator is being pumped into the warm engine block. When the engine is turned off, the water pump stops circulating the coolant. This causes the coolant in the vicinity of the engine block temperature sensor to rise. This may cause the electric fan to increase in speed for a few minutes after shutdown.

BMW-North 12-11-2015 07:38 AM

e46 electric fan guide

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