IMS Bearing Questions

[Gas Junkie]

Hello Folks,

A few weeks ago I was driving my Boxster and noticed a unusual noise. It was a crunching noise. It occurred periodically and seemed to be dependent on engine speed although it was not in sync with the engine. I drove the car again and it still had the crunch but after a while a new noise started. The new noise sounded like a bearing going out (whirring noise) and the pitch was completely in sync with the engine speed.

I drained the oil and cut open the oil filter. I did find some debris. Probably enough to cover the top of a pencil eraser. I dragged a magnet through the debris and about half of it stuck. I removed the sump pan and only found a few small pieces of debris, one of which was stuck in the oil pump pickup.

I am thinking the IMS bearing is in the process of failing. The car is an early 2001 and it appears, based on engine serial number, to be a double row bearing engine. I will verify this before ordering parts.

I am thinking about doing the L&N Retrofit but there is a statement on their website that worries me.

Also, if you have already had a failure where ANY debris has collected in the sump or on the magnetic drain plug, and IMS Retrofit™ cannot be done. No exceptions!

Taken on face value, it would seem my car is not eligible for this repair. I am wondering what the problem is? When does it go from noisy to failure? It seems the bearing extractor discussed on the L&N website attaches to the bearing support shaft and, with force, overcomes the spring clip that holds the bearing in place. It looks like the bearing support only contacts the inner race of the bearing. So if the bearing is the least bit compromised I would think the puller would just yank the inner race out leaving the outer race still in position. Anybody have any input?

So the items I need input on are;

1. Has anyone else experience the noises I described prior to an IMS failure or replacement? What else could it be? I would have done some stethoscoping but I was worried about running the engine any more.

2. Why can't I do the L&N Retrofit when a seemingly miniscule amount of debris is present? Could this debris be from something else? If I'm not eligible, what are my options? Is a complete tear down required?

Thanks in advance for any help.

[tonythetarga]

Are you planning to do the work or are you planning to have a mechanic do it for you? How many miles? I think the place to start is with an opinion about what the problem is after a mechanic looks at the car. It might likely require the trans to be dropped and the IMS inspected visually before removal. At least you'll know where you stand at that point.

If you are doing the work yourself, there is lots of discussion about what some debris can do to the engine and where to look. Without physically looking at your situation, you are bound to get opinions all over the place. Pictures will help too.

All I can say is not waiting for a failure and replacing the bearing is a much preferred solution. I replaced mine with 67,920 miles on it and have pictures posted. The bearing looked fine from the outside but when the seal was removed there was oil in it and no grease. The balls were OK but it would just have been a matter of time before it would have crumbled. The $1000 bucks was well worth it!

I hope your engine is salvagable. Good luck.

[JFP in PA]

Originally Posted by Gas Junkie

Hello Folks,

2. Why can't I do the L&N Retrofit when a seemingly miniscule amount of debris is present? Could this debris be from something else? If I'm not eligible, what are my options? Is a complete tear down required?

Thanks in advance for any help.

See my post in the IMS thread below on this exact subject..............

[feelyx]

In your case as you described, I would pull the filter housing and pull the bypass valve out and see if any debris is stuffed under there. You just hook the plastic piece in the bottom of the housing and give it a quick jerk and it pops out.

You will have to pull the oil pump and inspect for debris in the bypass. and gouges in your pump.
There is a shelf, that catches oil under the IMS, you might be abe to get one of those bendable magnets up there and see how much metal is really in your engine.
Pics of everything really helps too.
The LN puller is the best tool for the job, very well designed for the job. Snapon makes a race puller but I don't have the part # for it.

[Gas Junkie]

Thanks Tony.

I am still trying to decide whether to tackle it myself or take it to a mechanic. I live in North Alabama and we don't have too many qualified Porsche shops in the area. I am a pretty experience shade tree mechanic. I have read a good bit about the procedure and the only thing that makes me nervous is the extraction of the bearing.

The car has about 50,000 miles on it. Mostly daily driver stuff but it gets a few full throttle runs most every time I drive it.

At this point, I am sure the IMS bearing needs to be addressed whether its the culprit of the noises and debris. It just a matter of how I do it and if its too late for the L&N Retrofit

I have enclosed two pictures. The one with the WD-40 tube in the upper corner is pretty much the extent of the debris. Some metal flakes are missing from the magnet test. The other photo is a close up of the debris.

[Gas Junkie]

To JFP in PA, I reviewed the thread "What actually, IS the extent of the damage when the IMS goes?". Thanks for the pointer.

It seems to me that removing the IMS bearing and evaluating how far gone it is, i.e. how much grit/debris has been released, would be the right thing to do. If it appears to be mostly intact and my inventory of debris seems to be in line with the condition of the bearing, I should be able to clean things up the way feelyx describes, replace the IMS bearing, run the car, change the oil after a few hundred miles and evaluate the filter? If its clean, I am good to go?

[tonythetarga]

hard to tell from the pictures but it looks like chain tensioner debris. Is all that metal or is it plastic?

[Gas Junkie]

Tony,

The debris is mostly plastic. I really looks like bug parts to me

Feelyx,

I just checked the bypass valve in the oil filter housing and it was clean as a whistle.

Is there one oil pump or one on either side of the engine?

BTW, there didn't seem to be any affect on how the engine was running. Maybe a slight misfire but it could have been my imagination.

Thanks for everybody's help.

[JFP in PA]

I think that Tony is on the money here, that looks more like the wear pad from the chain tensioners, or possibly some sealant that has broken loose. IMS debris is a very small, but gritty and shiny metal, and usually ferrous (can be picked up by a magnet).

I really would not be considering pulling the IMS to determine how bad a shape it is in, if there is no real accumulation of grit in the pan, it may have wear but is not yet terminal. As replacing the tensioner(s) with the worn pads is going to put you in the position of having to lock the engine down in the same manner you would to do an IMS upgrade, I would just do both and be done with it; otherwise you get to do everything twice.........

[tonythetarga]

You got some good advice from Jeff.
I did my 911 with the LN bearing but the Boxster with the Pelican kit. LN says that the 'lifespan' is about 50k and Pelican says their range is 30-45K. I went with the sealed Pelican bearing (kit works for both single and double row) and will change the oil every 5k or once a year, whichever comes first. The difference in price was worth it to me. You will need the 'tool' to do the job and my local shop had one, so all I needed was the bearing kit.
A 'while you're in there' suggestion is replace the AOS if it is older than 2 yrs, which is relatively easy with the trans out of the way.

[Gas Junkie]

I have replaced the IMS bearing and the old one was pristine. No apparent damage to the seals. However, I wiped the bearing down after removing it and put it on a paper towel. I noticed later some oil had apparently seeped out of it. So I think (dangerous, I know) oil can get around the seals and break down the grease even if the seals are intact.

I did find the smoking gun for the noise I was hearing, the water pump. I removed the belt and turned it by hand and it wasn't smooth. Upon removal, I found the shaft was slightly cocked and the impeller has some of the tips missing. That would account for the crunching noise as well as the bearing whine.

So where do these pieces of impeller tend to collect? Should I really sweat them?

[BYprodriver]

Originally Posted by Gas Junkie

I have replaced the IMS bearing and the old one was pristine. No apparent damage to the seals. However, I wiped the bearing down after removing it and put it on a paper towel. I noticed later some oil had apparently seeped out of it. So I think (dangerous, I know) oil can get around the seals and break down the grease even if the seals are intact.

I did find the smoking gun for the noise I was hearing, the water pump. I removed the belt and turned it by hand and it wasn't smooth. Upon removal, I found the shaft was slightly cocked and the impeller has some of the tips missing. That would account for the crunching noise as well as the bearing whine.

So where do these pieces of impeller tend to collect? Should I really sweat them?

Good work so far! The WP impeller pieces are loose in the coolant passages & some of the smallest passages are in the heads which cause hot spots & cracking the heads. So you need to find all the pieces to prevent future cooling problems.

[Phillip Jones]

If you get in over your head on something try Casey at Eurasian Auto or Carl at Momentum in B'ham. Both extremely experienced porsche mechanics.