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Hello all,

I am now ready to take the jump and have my IMS replaced on my 2003 996 C4 Cab. MY2003 has 80K miles on the clock. I am the 2nd owner and do not have all of the records from the previous owner. All I know is the car was maintained by what used to be Barrier Porsche (now AutoNation) in Bellevue, WA. There is no record of an IMS replacement in any of the records that came with the car. I would assume there would be, if it had been done.


I am going to have the work done at a local very reputable indie dealer here in Bellevue, WA.


The attached file is the Quote.


I have done extensive reading about the IMS and its replacement, but now that I am getting ready to pull the trigger, I have some questions for the forum.


As a side note, my AOS was replaced last year. 


When I look at the quote, it looks fairly straight forward. What am I missing?


What can I expect after the work has been completed? What other items/parts/procedures need to be looked at or changed out while this work is being done (other than what they have noted on the work order)? 


I would assume they will look at my clutch/flywheel assembly, water pump, my transmission and ???


I realize this is a fairly broad question, but thought I would ask to see what else might be addressed while they are doing this work and what I can expect after the work is completed.


What type of driving can I do after the work is completed? Do I need to break it in, for example?


I trust these guys as they have always done excellent work.


Any additional thoughts? Any insight?


I appreciate your help.


Thank you,




Edited by Loren
quote removed at the request of the original poster
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Why not do the clutch too? The incremental cost should be small. I see you have selected the LN ceramic single row IMSB. Did you consider doing the LN/Raby "solution"? If you plan to keep the car for a long time you might want to pay the extra for the "solution". Good luck.

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I don't see either in your post or the estimate sheet what the miles are on your car.  That might help the members respond with more 

accuracy.  If missed it I apologize in advance.

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For what its worth, if you plan on keeping the car , then do everything an 80K car will need. 996, like any Porsche 911 has a fairly well

documented history of things that break/wear out. At 80000 miles, you are at the point where stuff happens. So,,, yes, do the IMS, do the rear seal, the AOS, bellows and ALL the coolant lines, as well as the **** coolant tank, including a new sending unit and the blue pressure cap upgarde. Do the water pump, and thermostat while you are at it. Clean out the throttle body, etc. Yes do the clutch, etc.

I doubt the flywheel is out of round or damaged. Not sure if your year was a single or double.

Radiators will be another area to keep an eye on. Theyre cheap in comparison to over heating an M96 block which will render you 996 into a very expensive lawn ornament.

If the car trani is manual, its the perfect time to refurb it. If the car whines coming off of Hi Rev driving or you have 2nd gear pop out, or synrchros that clunk, then its time to rebuild it.

I did all of this on my 00 C2 6MT coupe at 92000 and have had zero problems since. Car is now well over 100K and humming along as good as new.

The peace of mind far out weighs the costs. Plus , it WILL help future valuations when you do sell out of it. Why spend $2K now , only to have to spend another $2K 6 months from now, and that much again 6 months later.

Goodluck. Keep everyone posted.

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Hello all,

Thank you so much for the replies and the advice. I appreciate it as it gave me some great talking points when I met with the guys that are doing the work.


There are a couple of reasons I am going for a simple IMS bearing replacement solution. I will never drive my car on the track. I drive my car in the city and haven't and don't plan on any long road trips in the near future. The Jake Raby LN Solution with DOF is over kill for me. My understanding is that I am getting a replacement with ceramic bearings and it will take the high temperatures and lack of lubrication much better than the existing bearing. The other of course is money. If I had $3 or $4,000 dollars, I would buy myself a different car (see below).


The thought that my beautiful Porsche could potentially become a lawn ornament has haunted me for over a year now.


The guys that are doing the work told me they consider the bearing a 'replaceable' part and the replacement will last for about 50,000 miles. This is for 'normal' wear and tear of my Porsche. I think it will be sufficient. If any of you think I am making a horrible mistake, please let me know. I think it will be okay.


I had the AOS flipped out last year, but they are going to replace it again with this job. They will also look for any leakage/issues with my water pump, they will look at the flywheel and clutch which was replaced last year and has ~11,000 miles on it. It seems to be working fine, but we will see. I don't hear any whining from my transmission and it doesn't pop out of gear. It shifts smoothly with no issues. I am curious about the intake and the throttle body work. I don't have any issues now, but will be looking for the types of things that may be indicators of trouble ahead. And, I trust they will let me know if anything else on my car needs attention.


As far as all of the other items noted in your replies, the car was very well maintained when I bought it and I have continued to have it checked out and have updated parts as necessary. I don't feel like I need to do a major over haul at this time.


I do appreciate the note about the radiators, I will keep it on my wish list as well as my exhaust system (I do have a small problem there...).


I try to stay ahead of everything that should be replaced and taken care of. I have never had a CEL and for that I am thankful...knock on wood.


I am only doing the IMS for preventative reasons and for peace of mind. 


I love this forum and I appreciate being able to ask what might have seemed like a silly question. It wasn't. Your feedback was quite helpful.


btw...when I was at the shop, I saw a beautiful early 2000 CarreraS Turbo, midnight blue/grey. The curves on that car were absolutely stunning. If I decide to trade in my car, I definitely know the direction I would go. Not only is it fast, it is exquisite. 


Thanks all!



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Hi Julie,


I'm also in Bellevue. I had my AOS done at Chris' German earlier in the year. I was also going to get the IMS done at the same time but it turns out that my car has a rebuilt engine and the IMS had been replaced with the non replaceable kind found on the later cars. Apart from Chris', I also go to Squires and on occasion Bellevue Porsche (formerly Barrier). PM me if you want to discuss specifics further.


If the AOS was already replaced, I'm not sure why it would need replacing again. Granted it is only a $150 part but why replace it unless there is a reason to do so? When they are doing the IMS, they will be able to inspect the clutch and flywheel. In my case, the clutch did not to be replaced so it was not done. The previous owner put a new clutch in a 73k miles and I am at 86k miles. Again, I tend to believe in replacing what needs replacing. I'm not aware of any particular "post-operative" care that's required.


If there is no evidence that the water pump has been replaced, I would have this done. If, however, it was done less than 40k ago, I'd leave it alone. If there's not evidence of coolant leaks (telltale white stains in the engine compartment especially on the tubes), I would leave that alone. However, it is worth having the latest "blue cap" for the coolant tank if you do not always have this. It is probably worth doing draining and replacing the coolant, transmission oil and brake fluid especially if you do not do not know when this was done.


Hope this helps.



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I would think about the coolant reservoir, coolant level sensor and a new pressure cap. My coolant tank started to give problems at about 9 years of age at 45K (2003 996 C2).  Coil packs are also worth doing.  One of mine started to split at 55K and at the same time I put on stainless steel silencer boxes by Dansk.

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What I can never understand about this later bearing change is why direct lubrication is not provided through the normal engine lubrication system. It is not unusual to find roller bearings lubricated with sump oil. It was being done with the BMC Mini which had a combined engine and transmission sump in 1959.


Would it be possible to drop the sump pan and prise out the bearing seal to achieve this?  I have a feeling I have seen this questions asked before, but can't remember the answer.





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Here i found a possible solution to the so-called "non replacable bearing" maybe something to consider? https://vimeo.com/118923581


That entire idea is more than a little scary............particularly when the bearing you would be replacing is one of the least troublesome, and its replacement is a complete unknown.

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This is not possible in my view, only by removal, gearbox, clutch, flywheel and shaft cover, but i could be wrong.


You are correct; you cannot see the IMS from the sump.  The trans, clutch and flywheel have to be removed. 

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  • 3 weeks later...



If you ever do get a CEL I have a Durametric you can use.  I'm local and would be glad to assist.  As long as your doing the clutch, the  IMS and the RMS, I would also recommend replacing the transmission fluid with a Porsche approved 75-90W oil and maybe upgrading the thermostat with the LN 155 degree one. You also might want to consider getting your oil tested after hitting 90K and upgrading to a spin on filter.   Remember brakes should be bleed every two (2) years.

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