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  #1  
Old 12-13-2005, 10:58 AM
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mystery noise, is this fan clutch

Under acceleration or load I am hearing a noise that is kind of a hiss or dragging kind of sound that seems to follow endine speed. This sound dissapears at steady speed and will return about a fraction of a sec after you floor it. With the hood up I cant hear anything similar while revving the engine. So, probably something fan related right? If the fan clutch or bearing is bad how do I know or test?

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  #2  
Old 12-13-2005, 12:38 PM
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Could it be the turbo? That would explain why you don't hear it if the engine isn't under load. Are you able to turn your fan by hand? (when the engine is off of course) Should have some resistance but not be totally stiff.
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  #3  
Old 12-13-2005, 12:44 PM
carson356
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hose

check the rubber hose on the side of the turbo, i have seen some split and cause this noise, about the diameter of a AA battery
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  #4  
Old 12-13-2005, 12:47 PM
Craig
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I doubt the sound is related to the fan or fan clutch because it is related to the engine being under load. The fan doesn't "know" is the engine is under load or not.
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  #5  
Old 12-13-2005, 03:43 PM
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Front wheel bearings??
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  #6  
Old 12-13-2005, 08:32 PM
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Ah-ha. Yes there is a hose broken. It is about the diameter of a AA bat. It goes from down low on the turbo to up on the turbo at the intake and is broken at the top. What does this do? If there is vacuum at the top end going into the intake then its probably a certanly that my car has been inhailing engine grime for at least a week.
The fan will move freely back and forth and feels smooth in consistant on its shaft. It has about 1mm of play in and out and when flexing left and right has a little play.
Im curious now about fan design. I am going to post that in a new thread.
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  #7  
Old 12-13-2005, 08:42 PM
Craig
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Quote:
Originally Posted by angst
The fan will move freely back and forth and feels smooth in consistant on its shaft. It has about 1mm of play in and out and when flexing left and right has a little play.
Im curious now about fan design. I am going to post that in a new thread.
The fan has a mechanical, temperature controlled clutch that "engages" based on high air temperatures. The clutch is the finned metal disk that the fan is bolted to. When it's cold, the fan will spin freely and will not rotate at full speed when driving. When it's hot the clutch "locks up" to ensure that the fan spins at full speed. A small amount of free play is normal.
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  #8  
Old 12-13-2005, 08:55 PM
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Quote:
Originally Posted by angst
Ah-ha. Yes there is a hose broken. It is about the diameter of a AA bat. It goes from down low on the turbo to up on the turbo at the intake and is broken at the top. What does this do? If there is vacuum at the top end going into the intake then its probably a certanly that my car has been inhailing engine grime for at least a week.
The fan will move freely back and forth and feels smooth in consistant on its shaft. It has about 1mm of play in and out and when flexing left and right has a little play.
Im curious now about fan design. I am going to post that in a new thread.
There is no vacuum on that hose so it shoudn't have sucked anything up. That is the hose that "shows" the wastegate how much boost is being produced and opens or closes it as needed. Mine was completely disconnected when I got it and it gave the turbo a great sound. It got a lot quieter when I reconnected it.
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  #9  
Old 12-13-2005, 08:57 PM
carson356
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Quote:
Originally Posted by angst
Ah-ha. Yes there is a hose broken. It is about the diameter of a AA bat. It goes from down low on the turbo to up on the turbo at the intake and is broken at the top. What does this do? If there is vacuum at the top end going into the intake then its probably a certanly that my car has been inhailing engine grime for at least a week.
The fan will move freely back and forth and feels smooth in consistant on its shaft. It has about 1mm of play in and out and when flexing left and right has a little play.
Im curious now about fan design. I am going to post that in a new thread.
the hose is a special material, i would try to get the proper one, send me your vin number i will see if i can get you the correct mb number
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  #10  
Old 12-13-2005, 09:26 PM
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Quote:
That is the hose that "shows" the wastegate how much boost is being produced and opens or closes it as needed
So it controlls the wastegate? if left in broken state wastegate wouldnt open and you would get more boost (a good thing, perhaps too much of a good thing)? or other way around and you are getting less than intended boost? I think there may be enough slack in it to use the existing piece, carson are you serious about it being special stuff?

Quote:
The fan has a mechanical, temperature controlled clutch that "engages" based on high air temperatures. When it's cold, the fan will spin freely and will not rotate at full speed when driving. When it's hot the clutch "locks up" to ensure that the fan spins at full speed. A small amount of free play is normal.
So, tempature controlled? The clutch doesnt engage/disengage centrifugally based on rpm? When you say mechanical do you mean the sensor will actuate something in or out in the same fashon as what the thermostat does inside the cooling system?
The reason Im curious about this is a Cummings mpg guide refrencing drivetrain losses and specifically went into detail about fan. I think a few of the guys on the Ford forum have done electric fan retrofits. Not that Im considering this for my merc, just figuring stuff out.
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  #11  
Old 12-13-2005, 09:59 PM
carson356
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hose

Quote:
Originally Posted by angst
So it controlls the wastegate? if left in broken state wastegate wouldnt open and you would get more boost (a good thing, perhaps too much of a good thing)? or other way around and you are getting less than intended boost? I think there may be enough slack in it to use the existing piece, carson are you serious about it being special stuff?
you could try a piece of fuel line, the worst it could do is come off, worth a try
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  #12  
Old 12-13-2005, 10:37 PM
Craig
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Quote:
Originally Posted by angst
So, tempature controlled? The clutch doesnt engage/disengage centrifugally based on rpm? When you say mechanical do you mean the sensor will actuate something in or out in the same fashon as what the thermostat does inside the cooling system?
The reason Im curious about this is a Cummings mpg guide refrencing drivetrain losses and specifically went into detail about fan. I think a few of the guys on the Ford forum have done electric fan retrofits. Not that Im considering this for my merc, just figuring stuff out.
Yes, the fan clutch is temperature controlled, not speed controlled. It locks up based on the temperature of the air behind the radiator. There is some kind of thermostat built into the clutch. I'm not certain, but I believe it is based on hydraulic fluid contained within the clutch.
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  #13  
Old 12-13-2005, 10:42 PM
carson356
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Originally Posted by Craig
Yes, the fan clutch is temperature controlled, not speed controlled. It locks up based on the temperature of the air behind the radiator. There is some kind of thermostat built into the clutch. I'm not certain, but I believe it is based on hydraulic fluid contained within the clutch.
it is a wax or parrafin type substance
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  #14  
Old 12-13-2005, 10:49 PM
Craig
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Originally Posted by carson356
it is a wax or parrafin type substance
Thanks, I knew there was something in there that expands with heat, but I wasn't sure what it was.
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  #15  
Old 12-13-2005, 11:40 PM
Brandon314159
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Fuel rated hose will work just fine. It gets "sorta" warm in there but not too bad. All it needs to be able to do is withstand the oil that gets in there sometimes.

If you don't replace it, you will have boost in excess of 28+psi and this will make your overboost protection valve kick in which will make your car surge under heavy acceleration.

Ask me how I know

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