Engine Whine getting louder

I know this topic has been disused, and I did a search but could not find a solution. I have a whine in my 100K 996 C4s 6mt. It seems to be this exact problem: 996 startup engine whine no belt - YouTube But that is not my video. It appeared about 3 weeks ago and has gotten a bit louder in the last week. I pull the serpentine belt and the sound remained, so I do not suspect any of the accessories. It appears both while stopped (in neutral) and while driving and matches the revs exactly. Its is far too loud to be considered normal engine noise, even my oblivious wife asked about it. Any thoughts are appreciated.

Don't run the engine any more. I hate to be dramatic but that sounds like an IMSB. I hope I'm wrong. But if I'm not all might not be lost. The engine can be salvaged. But if you run the engine any more the engine can be toast. Even if it isn't the IMSB that the noise is present with the belt removed is generally not a good thing. About the only thing I can think of that wouldn't be engine related would be a bad clutch release bearing. 'course, it you tell me the car's a Tip, never mind.

I'm betting it's the SAI pump making the noise. Mine whines occasionally, especially when it's cold in the mornings. It's a fairly common issue with these cars. I'll probably pull mine soon and relube the bearings. There's a DIY on rennetech.org, I believe.

Have you checked your power steering fluid level? But then the noise would be easy to connect to steering wheel movement. Sorry, you said the belt was off, never mind, that includes the steering pump.

SAI pumps only come on on startup.

Have to agree with Macster. That is not a normal engine noise and I would not run the engine. Logic dictates that - with the serpentine belt removed you have eliminated all accessories and belt driven components; thus it is something internal to the engine. Sorry for the bad news, but with 100km, and you gave no clue as to previous maintenance, timing chain pads, spun bearing, bad bearing, etc. Would be wise to drain the oil and check for metal particles and cut open your oil filter to inspect for metal fragments. Since the video is your exact problem, perhaps subscribe and see what the OP found or fixed.

Shot in the dark - AOS problem?? Sometimes they do Screech, buzz, yodel when the diaphragm goes bad. Remove the oil fill cap and see if it changes the noise. This is not always a definitive test but it is quick and free.

Forgot to mention but you need to get the car flat bedded to a qualified/experienced Porsche shop and let an expert listen to the engine. He will strive to pinpoint where the noise is coming from as quickly as he can. Knowing from where in the engine -- if it proves to be from the engine -- then helps one better guess at the cause. I must stress that you should not run the engine any more other than in the presence of and under the supervision or direction of an experienced tech. While the noise might be from a relatively speaking benign cause it might not be and thus any further running of the engine can just make the situation worse. There are times when one can attempt to diagnose what may be wrong, there are other times when this is best left to a pro. This is one of those times best left to a pro. Just to be safe.

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Ugh. Well, I was hoping to do the IMS when the clutch needed replacing but I guess I will have to suck it up now. [Insert string of cursing]. I really hope this turn out to be something else, but I am afraid this isn't going to be a pleasant conversation with the mechanic. The AOS was replaced 1000 miles ago by the previous owner.

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Don't assume things. Have your mechanic do a proper diagnosis and tell YOU what is wrong. You shouldn't be telling HIM what's wrong based on a few posts over the internet.

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Ha, fair enough. No need to be pessimistic when hope remains alive!

Just to update the thread; I took it in to TPWS here in Austin (well respected independent Porsche shop) and they called me and said that they didn't really think the noise was significant. They felt it was most likely a clutch release bearing. Seems odd to me, but I trust their judgment. The clutch is probably within ~5,000 miles of the end of life so I am having them to do that and the IMS/RMS while they are in there. I will update later to see if this truly solves the issue. Amusing side note: Frannie runs the shop and she sounds like a church lady you should getting baking tips from not the kind of women who would have opinions regarding LN Engineering VS. Pelican IMS replacement parts.

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You should hear the "Tips" she gives after she drops a wrench on her foot. (J K don't know her or the shop)

LOL, so once again the paranoia hits again... Engine whine = possible IMS = don't drive anymore = clutch release bearing Meanwhile did you or the techs even pull the sump or inspect the oil filter at the least? I mean I don't automatically assume my migrane headache is a brain tumor. But at least if I suspect something isn't right, I at least get a basic diagnosis like an MRI...

Did you notice any change in noise as you depress and release clutch (in neutral of course)? While I agree with the "change IMSB while your in there" theory, I just hate guessing what a problem is.

I am very curious about this. I too have a "whine" that follows the rpm. The IMS was just replaced by the PO along with clutch and water pump. I took it to House Automotive in Pasadena where it spent most of it's life and I even let the mechanic ride in it. He said the sound was "normal," not anything to worry about mechanically. He did suggest to change the serpentine belt, which I will do but haven't gotten around to it yet. I'm also going to change the two rollers "while I'm in there."

You forgot to ad "flatbed to shop" which seems to be a standard answer.

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Well, they are going to do that when they replace the clutch. I just replaced the oil 800 miles ago (argghh) and there was no metal in the filter at that time. Nope. Which is why I still feel like the bearing seems like an unlikely culprit. But they did say that was "normal noise". Paranoia indeed!

So this is odd. I got a call today that they were replacing the clutch, and attempting to replace the IMS when they discovered the engine was the later, non-serviceable, IMS. It was my understanding that this was only found in the M97 engine? Why would someone have put an M97 in a 2004? Or were some late 2004 cars shipped with the later IMS? Their have been two previous owners of the car and the one from whom I bought never mentioned anything about an engine change, but he was pretty forthcoming on everything else (especially since an engine change is kinda-sorta good in this situation). Sucks not being able to swap the IMS without cracking the case.

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Odd indeed, I would question your tech's competence. If they were on the ball, they would have checked the engine number with the vin and established some facts: 1- the engine and chassis numbers match (tech is crap) 2- engine is not original engine, but from a later 997 (how likely you really think this is?), corroborated by comparing engine with chassis number get that clarified, and decide where to go from there

No first hand experience here but I've seen a few posts before complaining the same with no resolution. See this thread especially reply from Hartech on page 2 http://www.pistonheads.com/gAssing/t...ngine%3F&mid=0 Re your engine, just google some pics of 996 and 997 engines, i'm pretty sure you can tell them apart and see which one you have.

If PO got remanufactured engine from Porsche after mid 2000's, there's a good chance it could've had the larger bearing. Take a look or take a pic of your engine serial number to see if it has "at" in it. However, I still don't see how a whine automatically requires IMS change.

OP - your very hard to replace IMS bearing, while not being bulletproof, does have a lot better track record than the smaller single row bearing that is replaceable.

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Finding the larger bearing in an M96 is not at all unheard of. It does mean that the bearing was replaced after about 2006, and likely by a Porsche dealer's shop. I have an '01 C4 that had this newer bearing installed in 2011 by the prior owner. If it was replaced at a Porsche dealership you might be able to find out more info about the circumstances by contacting the dealership. Also, at pointed out above, check to see if the serial # has the letters AT in it which would indicate a factory rebuild. The new bearing is much more reliable than any prior generation bearing, and since I have this bearing in my car my concern is more for the several other modes of failure than can occur.

I wanted to follow this up in case someone else was having this problem. First, thanks everyone for their input. Regarding the whine: The clutch replacement did eliminate it. In discussions with the mechanic, he is aware of no audible whines that he would consider "major". In his experience, those rev-matched whines only come from the throwout bearings or accessories. Regarding the engine: It is a re-manufactured M96. The first owner must have had it replaced under warranty and the later IMS was installed by Porsche. This was apparently common. According to him, and other posters in this thread, the non-serviceable IMS _almost_ never fail. He said he had only ever seen one give out.