Finished Clutch / IMS Job, now have scary mystery squealing noise
 

I was planning to return home tonight and write up my IMS experience for posterity. Instead, I find myself pondering a worrisome noise that started as soon as I fired the Boxster up after the job.

To set the stage:

I just replaced the clutch w/ sachs kit, pilot bearing, throwout bearing, clutch release lever, installed a low mile resurfaced second hand flywheel out of a wreck, replaced IMSB with Pelican / OEM type replacement bearing, bolted everything back up and torqued it all down.

The noise is a high pitched squeal, sort of like a bad wheel bearing or belt. It only seems to happen under engine loading, but does not depend on clutch position or gear.

I noticed it immediately when pulling out of the garage, giving partial throttle. When driving, the noise is only present when accelerating -- it goes away when I back off the throttle.

I can also make the noise when not moving in two ways:

Firstly, with shifter in neutral and giving it throttle, the noise is present while engine speed increases, but not when it is constant or falling.

In gear, when I slip the clutch at idle against the brakes by using two feet I can produce a constant squeal. I did this while the car was on a lift while an associate poked around underneath. He seemed to think it was coming from the driver's side axle area.

Some thoughts:

It shouldn't be the IMS bearing (god help me if it is!) or serpentine belt because they shouldn't care about load, only engine RPM or rotational acceleration. It shouldn't be the clutch, CV axle, or wheel bearing because I can make the noise while stationary in neutral (by poking the throttle). It shouldn't be the motor/trans mounts or dual masses of the flywheel because of the continuous nature of the sound, which means it has to be something making full rotations.

I am stumped, and scared. Please give any constructive input. I will try to make a recording tomorrow and will not be driving the car until this is solved. Thanks.

Oh, by the way car drives fine, clutch feels good, although it engages very low.

You received the wrong clutch disc, or installed the disc backward.. The center hub on some discs are thicker than others, even with Sachs we find inconsistencies in this area..
Been there.. I'd bet lunch on this.

I definitely put the flat side towards the flywheel, so maybe the clutch disc was wrong?

If so, and thinking wishfully, will the clutch break-in period smooth it out?

Will this account for the low engagement point?

I didn't know you could resuface the dual mass flywheel successfully.... who did the work on the flywheel?

I used sachs clutch kit k70290-01, which is definitely referenced as the right one for an '00 Box S.

Feelyx -- the DMF was resurfaced by a local shop in Queens, they do them all the time for BMW's etc...

BB, sounds like Jake also said your clutch disk might be installed backwards. On this clutch disk, the center section is bowed out towards one direction. Which orientation did you install the disk: Bow towards the flywheel or towards the transmission?

Pilot bearing...? Does the pitch frequency increase when rev'd up..?:confused:

Here's video:
Mystery squeal after clutch / IMS bearing replacement - YouTube

seems to be from driver's side of engine.

Hi BB,
For what its worth... I was told by a German auto mechanic here in So. Cal. that DMF typically are not machinable without completely being dissembled, machined, and rebuilt with new everything. He said it was more cost effective to purchase a new one. This fellow is from Germany and has been a Merc, BMW, Porsche mechanic most of his 60+ years.
So unless the machine shop there in NY has a really effective way of assuring the flywheel is locked down and doesn't move or they rebuilt the whole thing I'd almost suspect the flywheel as being warped or as mentioned the clutch disc is wrong or is compromised somehow. As far as being backwards it's pretty hard to put one that has a dome on it in backwards. I would think you would notice it as soon as you attempted to install the pressure plate. I've only done one so I'm not an expert but just some thoughts... :) Good luck, Cheers

I have never seen a resurfaced dual mass flywheel that worked, and taking one apart is just not economically feasible, which is why they are replaced when they are no longer flat. Most attempts end up with an uneven surface or kill the elastomeric material and defeat the purpose of the dual mass.

Jake has a valid point on the disc, some aftermarket discs are thicker in the hub area than the OEM units and cause no end to problems, which are often very difficult to diagnose. If it is not an OEM disc, or had not been checked against an OEM disc before installation, I would consider looking there and checking that flywheel for trueness as well......

a bad flywheel shouldn't cause the issues that I'm seeing though, should it?

At this juncture, no one really knows for sure what the issue(s) is (are); regardless of their basis in fact and experience, all suggestions are conjecture and nothing more. I have seen the exact problem Jake mentioned; I have also not seen a resurfaced dual mass work correctly. That said, I doubt the dual mass can make a noise, but I do know the wrong clutch disc can make all kinds of noises. In addition, I also know that if the car was in my shop and made noise after reassembly, it would already be apart to see why…………… It is not going to “heal itself”. You have work to do.

Yep, time to dig back in there or hire a new mechanic. :)

I dropped the transmission with the slave still attached. It seemed to be in the right place in the release lever.

http://986forum.com/forums/uploads01...1345600262.jpg

Sorry for the poor photo, but this shows the clutch disk with a bit of scorching near the the fastener. This probably occurred while we purposely made the noise on the lift.

http://986forum.com/forums/uploads01...1345600364.jpg

This is what the pressure plate looked like.

http://986forum.com/forums/uploads01...1345600398.jpg

The throw out bearing that I installed was for a 987 (pelican said this was the only one they sold) and I had to buy a new ball pin and release lever for it. This is the old OEM 986 pivot piece that was in there from the factory (or last clutch job). I left it in even though the new release lever didn't seem to have grooves for it. Maybe that was a mistake?

I still don't know what was causing the problem, and am not sure if the clutch disk is still good... Not really sure how to proceed here.

New reality:

It's not the clutch. I started engine up with only the flywheel attached, and it still makes the high pitched squealing noise when you poke the throttle, but only during crankshaft loading (acceleration in this case)

Also, as I mentioned before, the noise seems
to be coming from the left hand cylinder bank.

I had to really beat on the ims shaft to remove the nut from the installation tool when I switched out the bearing, using pelican set screw method. I hope the ims cam chain sprocket isn't pushed too far in or something else that will require the case to be split!!! I am dead on terrified of this outcome.

Is there a safe way to get a stethoscope in there while making the noise?

Try turning the AC to Off. Maybe it's the pulley as it loads. Even the belt and other pulleys may be suspect? I also have a noise but it's more a whine than a squeal. Haven't had a chance to dig into it but the more I listen to it the more I'm convinced it's a hose sucking air and it goes into high pitch on high revs.

Might want to pull the oil filter and inspect before any more testing.

Plus 1 on the oil filter, also...if you don't have a stethescope, a dowel rod will work just as well (1/4 to 3/8 in diameter).

Have you taken your interior engine cover (behind the seats) off as well as the top engine cover? In listening to the video it almost has a failed bearing from a steering pump or AC unit...just a guess. Fingers crossed for you it is something minor and fixable.

The AC is off. I hear the noise when trying to start the car, and then again when trying to accelerate the flywheel. I do have a stethoscope, but the noise is too intermittent to fin using this method I think

Try removing the serpentine belt, that way you can eliminate the AC compressor, power steering pump, alternator, water pump, and idler bearing. Be careful not to run it any longer then needed to diagnose the noise with no cooling.

Just a thought.... what if you pulled the spark-plugs and rotated the engine by hand.... listen/feel for any roughness or rubbing. If there is some then pull the serpentine belt and rotate again. Like Eric G mentioned could be a bearing on anything connected to the engine. Maybe focus on those items closest to the driver side first. If you feel no rubbing without the belt then check all the items driven by the belt. If all that comes up negative then it possible the IMS sprocket moved during the IMS bearing install and is rubbing. If that happened then it's probably 'pull the engine time'.. :(
Wish we could help hands on.

Try putting on your old flywheel and see if the noise changes....

can't, don't have it anymore.... the machine shop resurfaced it, but then said it was bad. They still won't give it back without me paying out...

Here's a question:

What physical changes in the positions of various engine parts occur when the engine is under load (either accelerating or being loaded at idle by the clutch)? That will help me to narrow down the list of possibly interfering parts. I am also planning to slip off the drive belt to rule out any bad accessories. The motor was running / sounding fine before this whole mess (other than a cold startup rattle that I hear is pretty common on older boxsters)

Here is a real dumb idea. Are there any bolts that pertrude through the fly wheel hitting the engine block? Just another thought.

Thinking out loud... If a chain tensioner became hyper-extended and was stuck beyond it's normal range of travel due to movement during the IMS retro, would it cause a nasty noise like that? My brother developed a squeal on his 99 and it was worn out chain tensioners.

Mystery solved? Read on...

After running the car with the cam tensioners loosened with no effect, and with the serpentine belt off (no change here either), I pulled the flywheel and think I found the culprit. See pics below:

http://986forum.com/forums/uploads01...1345683326.jpg

Fresh nicks in the engine side of the bell housing.There were more of these.

http://986forum.com/forums/uploads01...1345683500.jpg
http://986forum.com/forums/uploads01...1345683601.jpg

These are closeups of the teeth on the backside of the flywheel.

The pics are not great, but I think that what they show is that the flywheel was off-balance and was oscillating under load, causing it to hit the case, producing an awful racket. The horizontal teeth on the backside appeared to be bent inwards a little bit.

The only thing that throws me off is that the noise did seem to emanate from the left cylinder bank, but it's possible that was due to acoustics within the engine compartment. I was never able to isolate it with the stethescope.

Am I justified in thinking this was the cause of all the trouble?

I guess I'll be ordering a new LUK flywheel and bolts in the AM. What a ********************show this whole job has been...

At least it wasn't the IMS sprocket... that's a good thing. :)

Black Box was it the fly wheel like you thought? I've got exact same sound and it's driving me crazy. Had serpentine belt changed today and pulleys checked no cigar. Mechanic thinks it might be the water pump but it's not leaking at all.

Even if the water pump is not leaking, it could still have faulty shaft / bearings....

Thanks Steve I guess it's a new water pump then. Needs to be done regardless I'd imagine been awhile hopefully solves the squealing.

The flywheel was not the problem. I replaced it, and still had the squeak. After spending more time under the car while an assistant revved it, I think it's coming from the left hand cam sprocket area.

Sorry to hear you still have the squeal. Have you considered it could be the water pump? Like I said earlier I have the same problem exact same sound as your video. Changed the serpentine belt and checked all pulleys still squeals. The shop that did it stated it seems to be the water pump but I didn't wanna pay to change it yesterday as they said its not leaking.

Curious if anybody else has noticed a squeal before changing water pump?? Seems to be quiet until car warms up as well.

It makes the squeal even with belt removed.

I've pulled my IMS cover off again, and with it off, with both rear tensioners off at TDC and with cams locked I see that the entire IMS shaft is cocked off at an angle.

http://forums.pelicanparts.com/uploa...1346209207.jpg
http://forums.pelicanparts.com/uploa...1346209226.jpg
http://forums.pelicanparts.com/uploa...1346209249.jpg

Could this be related to the noise?

Ouch! After the IMS retro-gone-bad fiasco I had a feeling it might be fecked. I'm not sure if this can be repaired without splitting the cases. Ever considered a nice used 3.4L? :)