996 IMS Issue - How real is it?

[LS1RX7]

Hi All,

I've been looking at a few 996's of late, and in doing some research have come across the IMS issue. I've had a chat with the service manager at my local PC and he's told me he's only seen 2 in 8 years. I know it can happen, and I know it does happen, but I'm just wondering how prevalent this issue actually is.

cheers

I recently purchased a 98 model 996 and did a fair bit of research prior to doing so. The IMS issue was something that although relatively un-common especially on the 3.4 with double row bearing, was something that made me a little nervous to the point that i decided to do the LN Engineering IMS upgrade on whatever car I bought purely for the peace of mind. There is a lot of information on the inter web and it is a reasonably easy task if you have basic mechanical ability and reasonable tool kit. I bought the bearing kit from Autohaus Hamilton for $1200 and the IMS tool kit from a seller on Ebay for $180. I also replaced the water pump and thermostat at the same time as this is another known failure point. The IMS took me a whole day to do on my own, luckily I had access to a hoist as it is a job I wouldn't attempt to do on the ground.

The water pump and thermostat took a couple of hours, the most frustrating  part of that was refilling the coolant and bleeding out all the air. I chose to completely flush the cooling system and replace the coolant while I was at it. I used AC Delco dexcool as it is readily availably and meets all the porsche coolant requirements and was recommended by a radiator reconditioner  I know, who said from experience it is the best coolant he has come across for aluminium engines. Use the genuine water pump with the plastic impeller, don't use the one with the steel impeller. The genuine water pump is only about $400.

Back to the IMS, although my bearing hadn't yet failed and there were no metal fragments  in the oil sample i took upon purchasing the car. When I removed the old bearing there was a substantial amount of dark smelly engine oil trapped in the intermediate shaft that had made its way through the original bearings seal's and was getting cooked everytime the engine was running without being cooled or filtered. The fact that the oil had made it to that point ( the other side of the IMS bearing) means it had already diluted and washed out the grease lubricant that this bearing rely's on and it was only a matter of time before the grungy oil that was building up in the intermediate shaft worked its way back through the bearing and caused the bearing to deteriorate and eventually fail. My car had 130,000k's on it when purchased and I'm glad I didn't ignore the IMS issue, it is obvious it would have bitten me eventually.

Anyone with a 996 or boxster or anybody thinking of buying one should treat the IMS bearing like you would a timing belt on other cars for peace of mind alone, they are usually replaced around the 120,000 km mark. There are other things that can go wrong with 996 engines but i have the peace of mind of knowing that I have reduced the risk considerably by replacing the IMS and water pump. 

[Peter M]

LS,

Great "hands on" work and write up.

I agree with your pre-emptive replacement approach.  However I'm not so sure that the bearing failure is primarily related to lubrication, whether that be grease, oil or combination thereof. 

For the purposes of research, could I have your old bearing please?  Happy to pay postage etc.

 

Regards

Peter

[firstone]

Hey diggin, if you have no further use for the tool I would like to buy it. Pm me if you're interested. 

[Skidmarks]

I just got the C4S back and they said that the IMS was fine. Still very happy to have had it done. Peace of mind and a great selling point. The new clutch, pressure plate and flywheel -  a bit of "while you're in there ..." as well as a full service added significantly to the bill but it's all as good as new and ready to enjoy. 

[Diggin]

Hey Skidmarks, Wasn't me. I think LS1RX7 is the person you're after.

 

Anyways, ended up getting a MY09 987 Boxter S.

[t888]

Hey Skidmarks, Wasn't me. I think LS1RX7 is the person you're after.

 

Anyways, ended up getting a MY09 987 Boxter S.

the one at gulsons for 69,990?  Can i ask how much you paid?

 

[LS1RX7]

Hey diggin, if you have no further use for the tool I would like to buy it. Pm me if you're interested. 

Hi firstone,

It was me that has the tool kit, when I purchased it I had intended to sell it on after completing the job, but have reconsidered now as i may buy another 996 in the future and it will be a handy kit to keep in the workshop. This is the one I bought on eBay it has gone up in price, I only paid $189.00 au in December 15, i hope this helps. Porsche IMS tool kit for 996 986 Boxster Carrera

[firstone]

☺ I realized my mistake but never got back to correct. 

Thanks for the tip. I want to do it myself as well. 

[LS1RX7]

LS,

Great "hands on" work and write up.

I agree with your pre-emptive replacement approach.  However I'm not so sure that the bearing failure is primarily related to lubrication, whether that be grease, oil or combination thereof. 

For the purposes of research, could I have your old bearing please?  Happy to pay postage etc.

 

Regards

Peter

Hi Peter, 

I'll check if I still have it, I have established a habit recently of throwing out worn or replaced parts, as I found I was hoarding too much stuff that was never going to be used again. If I can find it I'll get back to you for address details.

[dan_189]

Is that tool a replica of the LN tool? If it isn't it can only install the classic LN bearing rather than the pro one. If you're doing the solution I dont think it matters. 

[LS1RX7]

I used it to do the double row in my 1998 3.4L

 

[dan_189]

Ah right, so the 3.6 has a single bearing so do late 3.4s. 

There are 2 LN upgrades available:

Classic which is a ceramic single row or the pro which is a dual row in place of the single which requires a specific LN tool to install. 

[Macca]

100%, I was exhausted with reading and procrastinating. I purchased my 996 off a friend about 5 months ago. He replaced the OEM bearing (found to be in perfect nick) with a ceramic (old style LN - I am quite sure) about 3 years ago.  (80,000kms is the used by of that ceramic bearing). I bought the vertex bearing after owning the car for 3 weeks and its been staring at me from my desk on a daily basis. My indie will install the vertex next week. Will be interesting to see, but I wont be surprised if the ceramic is in perfect condition. Love the internet and the anxiety.  

EPS bearing in. Old bearing out. The IMS old bearing is in perfect nick. As expected.  

 

[LS1RX7]

Hi Macca,

The best case scenario is removing the old bearing to replace it as a preventative maintenance item and finding the old bearing in perfect condition. A less than ideal situation is to find that the bearing has already deteriorated and started shedding metal particles that have been traveling around the engine doing other damage, or worst case the bearing collapses and causes a catastrophic engine failure costing potentially 10's of thousands of dollars. In comparison the cost of replacing the bearing as a maintenance item every 120,000 kms or as LN suggests every 75,000 miles is relatively small for longevity and peace of mind. Just like a timing belt on other makes of vehicle that have to be replaced at around 100,000 klm's.

As for the EPS cylindrical roller bearing, I had a couple of people advise me to stick with the LN option as the EPS one hasn't been around long enough to prove itself and one Porsche specialist said he had already heard of some issues with it. I do believe that some LN bearings have had failures as well, nothings perfect but either option has got to be better than leaving the old bearing that has demonstrated the potential for failure whether it be from lubrication issues or lack of load allowing balls to skip as has also been  suggested. Either way there is a potential issue, some cars are doing 200,000-300,000 k's on the original bearing and some less than 60,000.

Regardless of which option somebody chooses, I would recommend doing an oil sample analysis at every oil change to establish a baseline and monitor potential wear so if there is a problem developing you can catch it before it does to much damage. You may also find another component at risk before it fails. We do regular oil samples on our earthmoving equipment for this reason. I know other components can fail other than IMS bearing,  but I now have more peace of mind after replacing the IMS and water pump and can enjoy owning my Porsche rather than stress about it.

The 996 has gotten a bad rap from the purists as well as it's reputation for potential engine failures, but if you can live with the boxer style fried egg headlights and treat the potential known engine issues as maintenance items, it is a much better car than it's predecessor's at a fraction of the cost of them or the 997 which still has the same potential issues. The 996 is a real Porsche and really is great bang for buck as long as you do what you can to make sure they don't go bang.

[WOKA]

And what about cylinder scoring or whatever..  I know its not IMS - but is there much weight to this issue as well..?  Separate thread perhaps but do you have any thoughts on that..? And what's this about cold starts..

Is the 996 really plagued..?  They got described to me yesterday as a 'ticking time bomb' and not a matter of IF but more a matter of WHEN.

 

[t888]

And what about cylinder scoring or whatever..  I know its not IMS - but is there much weight to this issue as well..?  Separate thread perhaps but do you have any thoughts on that..? And what's this about cold starts..

Is the 996 really plagued..?  They got described to me yesterday as a 'ticking time bomb' and not a matter of IF but more a matter of WHEN.

 

it really happens. A for "IF but WHEN" no mechanical part will last forever, regardless of which kind of car. Google "bathtub curve".

[LS1RX7]

Hi WOKA,

I believe there are several other potential issues with the 996 as I did a fair bit of research prior to buying one, but that goes for any car really especially when you consider that early 996's like mine are 17 years old now. Cylinder cracking is another issue that has occurred in some cars  but again this issue is not exclusive to Porsche 996's, cylinder cracking is a risk to any internal combustion engine. A bit like IMS bearing issues you don't hear about the many thousands of ones that don't fail, only the ones that do. I think the reason there is so much about the issues of the 996 on the internet is that someone that owns or wants to own a Porsche usually has a passion for the brand and will try to find out as much as they can, and those that already own a Porsche like to share their experience's good or bad because of that same passion.

I also think one of the reasons the 996 gets a lot of attention on the internet when it comes to failures is that the cost of major engine failure can be lots of money compared to falcon or commodore but owning a car like a Porsche 911 is a lot different to a falcon, commodore or other mass produced car. Porsche ownership is still new to me but from carrying out the IMS bearing replacement and water pump replacement as preventative measures I got to see first hand how well these cars are engineered and put together.

As for ticking time bomb, I think that applies to any internal combustion engine it's just that the Porsche engine is going to be more expensive to repair than a ford or holden but same goes for any european car. I weighed up the the fact that you can buy a good 996 for under $40,000 at the moment, (I paid $30,000 for my 1998 manual coupe with 130,000 km's and a complete service history.) against what else you can buy for the same money, remembering that a 996 is a 911 and a real Porsche, all 911's are considered to be supercars of their era. I negotiated my purchase on the basis that i always intended to upgrade the IMS bearing and replace the water pump as they are the two main items that can cause a major failure and are able to be carried out with the engine still in the car. I am also fortunate that I am able to carry out the work myself, at the end of the day it wasn't that hard, when you look at it a Porsche is the same as any other car in so much as it is just nuts and bolt's, I'm not a mechanic I just have a passion for cars and in particular Porsche 911's.

If you have some mechanical knowledge and ability there is plenty of information on how to do work on your 911 and that can make ownership both economical and enjoyable. If you have to put it into a workshop for everything in can get expensive. I maintain that in my opinion if you buy a 996 with a service history and deal with the known issues as maintenance items then the 996 is great value for money when you consider you are buying a true supercar.

[Jim45]

Anyone actually just replace the bearing with an OEM Porsche one if its being treated as a service item? - Or are the designs fundamentally different..?

On a side note the 996 I just bought had the clutch done 15k km ago and the guy was advised to leave the IMS bearing alone by an independent as it as it had the "newer" one?? I'm now deliberating whether to get it updated. I did speak to his mechanic and he said he had inspected it when the clutch was being done and there was no visible indication that there was an issue and there was no play??

Jim.

 

[dan_189]

There were revisions through the years. I wouldn't trust the original though. That mechanic wouldn't have been able to inspect it because removing it isn't overly simple.  For piece of mind get the LN pro. 

[Jim45]

There were revisions through the years. I wouldn't trust the original though. That mechanic wouldn't have been able to inspect it because removing it isn't overly simple.  For piece of mind get the LN pro. 

It's the next thing I'm going to do..

It's weird as the previous owner actually asked to have it done and was told don't.

Jim.

[dan_189]

When I was researching the 996 I called the dealership who told me "if it hasn't gone by now it won't". He was probably right but it's too big a risk to not have it dealt with. $1500 for piece of mind.  

[LS1RX7]

Hi Jim45,

You can't inspect the bearings condition without removing it, once you do remove it, it can't be re-used as the removal process relies on pulling from the centre stud. This puts pressure on the balls against the shell which in turn can create  small flat spots on the balls which if re-used can cause the balls to skip intermittently and the flat spots get worse and start damaging the bearing surfaces which starts a downward spiral of deterioration which can accelerate rapidly. 

Porsche doesn't sell the OEM bearing separately, you have to buy the whole  intermediate shaft assembly. There is some differing opinion on the cause of IMS failure, from lubrication issues due to the seals failing and allowing oil to pass through the bearing into the intermediate shaft washing out the original grease to lightly loaded contact allowing the balls to skip which then starts to multiply the damage. 

The other thing to consider is that there are many cars out there approaching 200,000-300,000 km that are still on there original bearing. The low km cars are the ones that seem to be most at risk, probably due to seals hardening through lack of use. early 1998-2000 model cars with the dual row bearing were at least risk with a 2% failure rate 2000 model onwards with single row bearings had a 5% failure rate. My car had 130,000km when I bought it last year  and i didn't want to take the risk leaving the original bearing in there. 

When I removed the bearing it was intact and showed no signs of wear or play however there was a lot of really grungy bad smelling oil that came out of the intermediate shaft itself from behind the bearing. This was engine oil that had made it past the original bearing seals and into the hollow shaft, the oil then gets cooked every time you run the engine and can't get back out to be filtered or cooled or replaced at scheduled oil changes if you maintain the correct oil level in  the sump. This oil breaks down and becomes acidic and if it works its way back into the bearing  usually due to lower than optimal oil level which may only be 1 litre of oil lower than optimal, it can start to damage  the bearing and cause the downward spiral that will continue regardless of oil supply. So whilst my bearing was still ok the bearings seals had been compromised meaning it was probably only a mater of time before failure cycle would have started had I not done anything about it.

My advice if you don't want to change it now would be to have an oil sample taken and analysed and then have another one at 5000km later to see if there is any over the top level of wear metals present, or if there is a small amount present  and in most normal cases there will be, compare the two samples and see if there is any dramatic increase to determine if there is a potential problem developing. Be diligent with checking your oil level and keep it at optimal level using the dipstick rather than the gauge but don't over fill it.

Having the bearing replaced should give you peace of mind. In my opinion replace the bearing with the LN engineering one and sleep better at night and enjoy your Porsche instead stressing about it.

 

 

 

 

 

[Hughesy]

My 2 cents

I've picked up an immaculate C4S that has a faultless ppi and is in showroom Cond. 

Im getting the Ln solution done before I drive her home 

you know it makes sense. If it's a 30 or 40 or whatever $$ car it's damn cheap insurance. 

Keep out of the kitchen if you can't stand the heat 

cheers lads 

[LS1RX7]

Agree totally Hughesy, you buy a Porsche to enjoy it, you don't want to be stressing about it.

[Whytar]

If it's a known issue that can be catastrophic, and an upgrade resolves the issue, I can't imagine a valid argument for not doing it upfront for total peace of mind... why would it even be a discussion point worth 3 pages of forum?