loud fan-like noise when rev-ing once car is warm (not fan clutch)
01-08-2007, 12:22 PM
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loud fan-like noise when rev-ing once car is warm (not fan clutch)
I met up with fellow UrS owner this weekend(thanks Tom) to take a look at his beautiful white S4's,. While there I asked him about the engine noise I have, and we are both still stumped.
The engine noise sounds like a loud fan (some might say jet engine like). When you first start the car there is no noise. Leave it running for a while and as the engine warms up the noise gets louder and louder. It does not occur when idling, only when being gassed... more gas.. more noise. It is also out of phase, so once you release the pedal you hear the engine wind down, then the loud fan noise about 0.5 second later.
The fan clutch was just replaced as I thought it was the cause (it was on the way out anyway, so no harm no foul). We checked the AC and it is not engaged when the noise is present. When I engage the A/C it makes it's familiar noise (that is drowned out by this other noise) and the second fan (electric) comes on as it should.
There isn't a ticking, or another noise, just the loud fan noise. It also seems to affect the "free rev-ing" nature of the engine.
I am in boston area if anyone would be kind enough to give it a look, but advice by itself is more than welcome.
Thanks in advance.
The engine noise sounds like a loud fan (some might say jet engine like). When you first start the car there is no noise. Leave it running for a while and as the engine warms up the noise gets louder and louder. It does not occur when idling, only when being gassed... more gas.. more noise. It is also out of phase, so once you release the pedal you hear the engine wind down, then the loud fan noise about 0.5 second later.
The fan clutch was just replaced as I thought it was the cause (it was on the way out anyway, so no harm no foul). We checked the AC and it is not engaged when the noise is present. When I engage the A/C it makes it's familiar noise (that is drowned out by this other noise) and the second fan (electric) comes on as it should.
There isn't a ticking, or another noise, just the loud fan noise. It also seems to affect the "free rev-ing" nature of the engine.
I am in boston area if anyone would be kind enough to give it a look, but advice by itself is more than welcome.
Thanks in advance.
01-09-2007, 07:25 PM
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Mot sure but
maybe a couple of tools you can use to check things out.
I've resorted to a broom handle a number of times to try and locate an engine noise. It works as a great stethoscope. Gently hold it against various parts of the motor and hold the other end near you ear. Just mind the rotating bits.
It's obviously on the reciprocating assembly, so try and isolate parts of it. If you can pull of each of the v-belts in turn and see the effect. Just keep an eye on battery voltage and whatever else you are affecting during this process. Don't do anything to leave you stranded.
I'm going to lean towards the fan clutch only because of the specific noise, and you should be able to isolate that pretty easily.
Any gauges or indicators reading any differently? If it were the fan clutch I might think the temp could be off a bit.
I've resorted to a broom handle a number of times to try and locate an engine noise. It works as a great stethoscope. Gently hold it against various parts of the motor and hold the other end near you ear. Just mind the rotating bits.
It's obviously on the reciprocating assembly, so try and isolate parts of it. If you can pull of each of the v-belts in turn and see the effect. Just keep an eye on battery voltage and whatever else you are affecting during this process. Don't do anything to leave you stranded.
I'm going to lean towards the fan clutch only because of the specific noise, and you should be able to isolate that pretty easily.
Any gauges or indicators reading any differently? If it were the fan clutch I might think the temp could be off a bit.
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