Loud wining sound
01-21-2013, 04:49 AM
#1
Rennlist Member
Thread Starter
Loud wining sound
"Whining" ^ typo
Wanted to get some input before I started to tear things apart, or jump to conclusions.
Background:
I've had my 2001 C2 for a few months now. It has 93k miles, no recorded history of the IMS bearing being completed (planning on upgrading it as soon as I have the time)
The Symptoms:
Inside, and outside of the car you can hear a very audible whining noise while the car is running, it is barely noticeable if at all at idle. As soon as you give the car some throttle, it becomes very apparent and obvious at as low as 1,500 RPM's. The whining gets louder, and higher pitched with more RPM's. It is not dependent on being under load or not, it makes the noise out of gear, in gear, clutch depressed, clutch released. It is strictly engine RPM dependent. It sounds very similar to transmission whine, at first I actually assumed it was the bearings in the transmission (common issue on the 996's I've read) but since the noise is not dependent on being in gear, I think that isn't the cause.
Stethescope Test:
After somewhat realizing it's unlikely the transmission is causing the sound, I used a mechanics stethescope to try to decipher where the sound was originating from. I first checked near the accessory belt. Every pulley sounded fine, with the exception of the alternator pulley. I attributed this to just the alternator making it's own noise, and noticed it sounded nothing like the whine while the Wife held RPM's at 1,500. I tested a few other areas around the top of the engine bay, and still couldn't seem to find the location of the sound. I then tested a few spots under the car, the variocam area was exhibiting the sound a little, but it wasn't too loud through the stethescope. I then tested a few areas where the transmission, and engine block meet, BINGO! 100% sure that this is where the sound is originating from, which from the little I know can only spell bad, expensive news.
It puts me back to the original Transmission whine idea, but this could be clutch related... possibly throw out bearing? or pilot bearing? I always figured those make certain noises at engaging or disengaging of the clutch usually... Another scary possibility is the IMS bearings starting to make some noise. I know when they completely fail they normally make more of a rattle... but I guess it may be possible they are whineing first. The sound has slowly been getting worse the past few weeks, I didn't notice it when I first bought the car, it may have exhibited a little bit, but most 911 H6's have a bit of a howl/ whine to them, just not this much.
Last bit of info, the clutch was replaced by the previous owner about 8k miles ago. It was done with the factory 3 piece clutch kit at Porsche of Honolulu 996-116-911-00 so the throw out bearing isn't too likely.
Any ideas?
Wanted to get some input before I started to tear things apart, or jump to conclusions.
Background:
I've had my 2001 C2 for a few months now. It has 93k miles, no recorded history of the IMS bearing being completed (planning on upgrading it as soon as I have the time)
The Symptoms:
Inside, and outside of the car you can hear a very audible whining noise while the car is running, it is barely noticeable if at all at idle. As soon as you give the car some throttle, it becomes very apparent and obvious at as low as 1,500 RPM's. The whining gets louder, and higher pitched with more RPM's. It is not dependent on being under load or not, it makes the noise out of gear, in gear, clutch depressed, clutch released. It is strictly engine RPM dependent. It sounds very similar to transmission whine, at first I actually assumed it was the bearings in the transmission (common issue on the 996's I've read) but since the noise is not dependent on being in gear, I think that isn't the cause.
Stethescope Test:
After somewhat realizing it's unlikely the transmission is causing the sound, I used a mechanics stethescope to try to decipher where the sound was originating from. I first checked near the accessory belt. Every pulley sounded fine, with the exception of the alternator pulley. I attributed this to just the alternator making it's own noise, and noticed it sounded nothing like the whine while the Wife held RPM's at 1,500. I tested a few other areas around the top of the engine bay, and still couldn't seem to find the location of the sound. I then tested a few spots under the car, the variocam area was exhibiting the sound a little, but it wasn't too loud through the stethescope. I then tested a few areas where the transmission, and engine block meet, BINGO! 100% sure that this is where the sound is originating from, which from the little I know can only spell bad, expensive news.
It puts me back to the original Transmission whine idea, but this could be clutch related... possibly throw out bearing? or pilot bearing? I always figured those make certain noises at engaging or disengaging of the clutch usually... Another scary possibility is the IMS bearings starting to make some noise. I know when they completely fail they normally make more of a rattle... but I guess it may be possible they are whineing first. The sound has slowly been getting worse the past few weeks, I didn't notice it when I first bought the car, it may have exhibited a little bit, but most 911 H6's have a bit of a howl/ whine to them, just not this much.
Last bit of info, the clutch was replaced by the previous owner about 8k miles ago. It was done with the factory 3 piece clutch kit at Porsche of Honolulu 996-116-911-00 so the throw out bearing isn't too likely.
Any ideas?
Last edited by ccaarmerciill; 01-21-2013 at 08:22 PM.
01-21-2013, 11:16 AM
#3
Instructor
Have hou run it with AC off? Mine makes exactly that noise, but with AC off...quiet. (Yes, I need to fix it but not critical right now to do so as it is -5 to -15 *C outside...)
01-21-2013, 06:14 PM
#6
Rennlist Member
Thread Starter
Sound is not A/C dependent.
In a little bit when my "assistant" comes home, I plan on trying to get a more accurate idea of where the sound is coming from...
It shouldn't be transmission related if the noise is made completely out of gear, as well as in gear correct?
In a little bit when my "assistant" comes home, I plan on trying to get a more accurate idea of where the sound is coming from...
It shouldn't be transmission related if the noise is made completely out of gear, as well as in gear correct?
01-21-2013, 06:17 PM
#7
Instructor
Correct! One way to remove accessories like a/C, power steering etc is to run it without the belt (only short periods, maybe 10s or so as there is then no water circulating to cool things down or generator charging battery).
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01-21-2013, 06:59 PM
#8
Rennlist Member
Thread Starter
I made a quick video of the sound... (posted in top of thread)
I'll remove the belt now to see if that solves it.
I'll remove the belt now to see if that solves it.
Last edited by ccaarmerciill; 01-21-2013 at 08:22 PM.
01-22-2013, 02:25 PM
#11
Instructor
With accessroies elimnated, the only other engine external thing I can think of is like a stone or bolt lodged between block and main front pulley (towards rear of car). Noise is the same with clutch engaged and not right which should elmnate transmission? Other than that...it is somewhere inside 
i'd start with trans out first to check flywheel and the support bearing to the transmission rod (not sure of the english name for it) before engine out. In summary, I'd go to a specialist.
i'd start with trans out first to check flywheel and the support bearing to the transmission rod (not sure of the english name for it) before engine out. In summary, I'd go to a specialist.
02-28-2017, 01:15 PM
#13
Rennlist Member
I know this is old but I stumbled upon it during some searching to try to figure out why my car is making a whine noise. Mine sounds just like the video. Did you ever figure it out ccaarmerciill? Anyone else have the same sound?
02-28-2017, 02:53 PM
#14
Rennlist Member
Have you tried clutch depressed and transmission in gear vs. out of gear with clutch depressed? Even though the clutch is down I wonder if its possible that the transmission input shaft is still spinning with the engine is there is no real resistance (IE: in gear).
To answer your question earlier - the pilot bearing is spinning when the car is not in gear. The thrust / throw out bearing spins when you have the clutch depressed. Although in its resting state I wouldn't be surprised if it is still spinning, just without much load applied.
To answer your question earlier - the pilot bearing is spinning when the car is not in gear. The thrust / throw out bearing spins when you have the clutch depressed. Although in its resting state I wouldn't be surprised if it is still spinning, just without much load applied.
