what does IMS problem sound like?

[drewbz818]

Just got a boxster, makes a sound when started cold for 1-2 seconds, is this ims?
if not what does it sound like and when does it make that sound?

[Wayne 962]

Yes, it very well could be. That and/or chain tensioners. Does it make the sound at any other time?

-Wayne

[drewbz818]

no only when i start it cold, any other things i should look for?

[Wayne 962]

Noise at cold start = probably the tensioners that have not gotten up to pressure quite yet. Mine makes the same noise, and I'm ultra-sensitive to it as well. I would probably leave it alone. IMS issues will make the sound at startup, and then will occasionally make the noise when idling as well.

-Wayne

[Dale_K]

My car makes a very brief rattling sound on a cold start that goes away in less than a second. Personally I'm convinced it's one of the chain tensioners. I had a BMW motorcycle that made the same noise and it was coming from a tensioner. I'm trying to put you at ease in the sense that some other cars make a little noise at startup.

[drewbz818]

I wanna say thanks to all who replied, feel better about my boxster now, rain should stop tomorrow will let my e30 rest, and pull out the porsche.

[thstone]

My '99 makes the same cold start rattling noise for about a second then quiets down to normal. Dealer says its the tensioners and nothing to worry unless it goes on longer or never quiets down.

[Andrew D.]

Chain tensioner noise on cold start-up is a fairly common, known issue.

[sjlee001]

I was driving from Chicago to San Fran when my IMS went. It sounded like somebody dropped a few nuts nuts into the engine compartment, literally.

I took it to the local Porsche dealer, who found metal particles in the oil filter. They took the bearing cap off and sure enough, the bearing race surface was badly pitted.

[Wayne 962]

Originally Posted by sjlee001

I was driving from Chicago to San Fran when my IMS went. It sounded like somebody dropped a few nuts nuts into the engine compartment, literally.

You mean when it finally went - it started to fall apart many miles previously. The trick is to catch it before then...

-Wayne

[NOTASIX]

Of all the IMS failures that we see, most of them occurred with zero advance notice. This was either due to the driver not being attuned to the engine and its "normal sounds" or the fact that no noise occurred.

No mechanical noise is a good one. The majority of the start up noises are related to tensioners or worn vario-cam wear pads in the earlier 5 chain engines. We hear noisy timing chains more at start up as well, but I've never heard any noise generated by an IMS bearing at start up. Start up noises can generally be eliminated by a proper, invasive service where the tensioners are cleaned or replaced along with all the vario-cam wear components being replaced along with the 4th and 5th chains in the 5 chain applications. The choice of Mobil 1 engine oil is generally the worst for keeping tensioners quiet at start up, I have eliminated those sounds simply by changing brands of oil.

Our direct experience with IMS bearing noises has been that they simply don't occur soon enough to save an engine. We have been working on the development of a means of noting IMS bearing issues before they become critical to the life of the engine. You'll see more about this in the future as it is in practical application testing now.

As Wayne stated, the key is not to wait until you are forced to replace a bearing or an engine, but to electively retrofit the IMS bearing while you still can. From the trends we have noted all IMS bearings will eventually wear out, its just a matter of time and luck. The service life of the factory bearing is certainly less than the remainder of the other wear components within the engine.

[eric523]

agree that it's likely tensioner noise at cold start, pretty common, especially with the Mobil 1 0-40 as Jake had said.

Yeah IMS noise is hard to catch. I've had only one customer notice the change in pitch of his motor at idle and knew enough about the problem to tow it in. We listened to it with a stethoscope and indeed it sounded ready to fail. Sure enough, when we pulled it out the bearing was about to go. Replaced with the L&N retrofit and all was good again.

We've started to make a habit of listening to the bearing at idle with a stethoscope when these m96 motors are in for service. Some of the bearings sound really smooth while others are quite grumbly. It's not the most perfect way of inspecting, but a few saves have been made though so we will continue to do this.

[Wayne 962]

Originally Posted by NOTASIX

No mechanical noise is a good one. The majority of the start up noises are related to tensioners or worn vario-cam wear pads in the earlier 5 chain engines. We hear noisy timing chains more at start up as well, but I've never heard any noise generated by an IMS bearing at start up.

I can't recall if I took a video of it, but the 996 that we bought "with engine problems" had a start up noise, then would run okay, and then start to make chirping noises. This is what the previous owner heard and then took it directly to a shop here in Los Angeles. They diagnosed that it needed a new engine, and then he ended up selling the car to me ($10K). We opened it up, and found this:

So, we were able to hear it definitely with this engine. When we replaced the bearing with the new Pelican prototype kit, the noises went away, so I don't think the chain tensioners were bad. So, at least in maybe rare cases, you can hear the bearing beginning to fail - I guess it just depends upon various factors. By the way, this car had 31,000 miles on it!

-Wayne

[Wayne 962]

Originally Posted by eric523

Yeah IMS noise is hard to catch. I've had only one customer notice the change in pitch of his motor at idle and knew enough about the problem to tow it in. We listened to it with a stethoscope and indeed it sounded ready to fail. Sure enough, when we pulled it out the bearing was about to go. Replaced with the L&N retrofit and all was good again.

I think it's going to be a foregone conclusion that everyone needs to do this at clutch time!

-Wayne

[drewbz818]

thanks Wayne for all the info, a little more at ease with my car. Still gonna change the ims jus for peace of mind, jus deciding if i should take it to a shop or attempt it myself. Several members on here have offered help so will see what im gonna do. Jus hate freakin out every time i hear something. I oppened this baby up the other day on the freeway and gotta say i thought my stroked out e30 was fast, aint got **** on this stock boxster, felt so agile and nimble. Hey can you send me a pic of where to listen with a stethescope to see if ims might be making any noise? Appreciate all the help and advice from you and fellow members. Any mechanics in LA that you recommend who price fairly?

[turboflyer]

Could we possible just be hearing a little hydraulic lifter build up from leak down on cold start up? My 01 has done that almost from day one. All oil lab work is normal. Car runs flawless, now at 76K. I too would like to check that bearing, but with the TIP no easy way, unless there is an access for the stethoscope probe. Then not knowing what normal sounds like unless it is growling and moaning would be subjective. Dont suppose there is a secret sound recording and of course a way to access the area with the TIP?

[Schumi]

Having been one to work with an engine with a similar bearing (in oil-bathed condition) fail, I can attest the the intermittent chirping.

We had a formula car with a wet-clutch gearbox where the main basket bearing was a large ball bearing. It was in a case halve that had sat for a long time and the bearing was either badly contaminated or damaged by it's special installation tools.

The engine would run great, but every now and then, under power, we would hear a short but steady chirp sound, similar to a slipping power steering belt, for 1-2 seconds at a time.


We eventually traced the problem on an engine-transaxle dyno to that bearing- there were bad wear marks on the races and certain badly worn balls in the bearing that were catching on the races and dragging themselves around, making the squealing noise.

This, from the pictures I've seen, is the what happens when the Boxster IMS fails- the balls get hot and friction starts to drag them around, and they wear the races until the races rip themselves up and the worn down balls can pop out and the shaft jumps timing.

[BerneseMtnDog]

drewbz818 as a newbie to Porsche last year and a generally decent home mechanic I can tell you doing the clutch, flywheel, ims bearing and rear main seal was a lot easier than it sounds. There's a lot of help here and Wayne's book is indispensable. I did the work on my car before the book was out and used his online tutorial along with some other folk's notes and suggestions. Been on the new clutch now almost a year and I like to think I did more thorough work than someone not emotionally invested in the car. Saved a pile-o-green too.

Steve
200 2.7L

[Wayne 962]

Originally Posted by BerneseMtnDog

drewbz818 as a newbie to Porsche last year and a generally decent home mechanic I can tell you doing the clutch, flywheel, ims bearing and rear main seal was a lot easier than it sounds. There's a lot of help here and Wayne's book is indispensable. I did the work on my car before the book was out and used his online tutorial along with some other folk's notes and suggestions. Been on the new clutch now almost a year and I like to think I did more thorough work than someone not emotionally invested in the car. Saved a pile-o-green too.

Steve
200 2.7L

When I first started working on the book, a bunch of "old school" Porsche guys were telling me that these cars (Boxsters & 996s) were too difficult to work on, and the secondary market would never take off. I didn't agree with them, and pushed on. Now, after writing the book and the early 911 101 Projects book, I would have to say I think that the Boxsters are easier to work on than the early 911s. Very few rusted bolts, clear snap-through engineering, intelligent design for manufacturing. Not to put down the older cars - they are like a hand-built Swiss watch. But if you've ever tried to work on a hand-built Swiss watch, you would immediately go nuts!

-Wayne

[intakexhaust]

Gotta love these post... working on these cars. Even Jay Leno had recently written an article of getting intimate with your car. This was brought on by him taking the McLaren in for an oil change. His crew or himself choose not to do it for various reasons (personally, I would... thought it was a BMW 5.0 V12 powerplant?).

Wayne's comment cracks me good... 911 - swiss watch. Well, the Boxster reminds me of a German cuckoo clock gone bad. Take that motor down to it's pieces and you have a real pile to put back together!