I have leak in rear main seal, 60K miles Should I replace IMS at the same time?


Asked by Feb 06, 2016 at 02:45 PM about the 2003 Porsche Boxster Base

Question type: Maintenance & Repair

18 Answers


IMHO - absolutely yes! Take care of the weak link in the car and you'll sleep better at night. Personally, I wouldn't drive one w/o LN engineering fix.

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Yes, without doubt. A large part of the cost is already being spent to remove the transmission and flywheel

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Makes sense to me, while the tranny is out. Also a good time to repack and maybe replace the axle boots, depending on condition. I did them while changing clutch and bearing along with the rear main seal in my 2000 996. Take care of 'em and they'll last longer than you ever dreamed. Good luck!

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Certainly. I agree with the comments above, and it's relatively cheap insurance - especially since the transmission is/will be out.

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I will be using one of these when it comes time. The direct oil feed IMS unit.

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The open ceramic bearings are obviously in direct contact with the sump oil. No tubing needed. You're asking for trouble.

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Make sure that this is truly a main seal leak and NOT the failure of the Intermediate Shaft Bearing. The IMS failure is a well known manufacturer's defect, that affects this year and others (I believe 1999 to 2006). If the IMS fails, there is no fix. Only replacing the short block and associated accessories. This happened to me. Now I have a giant, junk paperweight of a car. Not worth repairing and even though Porsche lost a class action suit for this very issue, I was not part of that class and didn't know of this issue. Porsche customer service REFUSED to even offer any type of compensation to assist in the cost of this repair. While I loved the Boxster, I WILL NEVER OWN ANOTHER PORSCHE AGAIN (due to the known issue that they won't now stand behind and the awful customer service!) BUYER BEWARE ON THESE YEAR BOXSTERS


To Michael Kane: You are aware the the OEM bearings are SEALED bearings, either one or two rows?? There is no safe way to unseal this type bearing to allow for a pressured oil feed line. The bearings must be changed, either to ceramic or conventional, but with open cages to allow submersion in the sump oil. Your set-up accomplishes nothing, only risk of a future oil leak, or worse.

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@copters, which year and model Boxster have you got? If you are near the Bay Area, I could be interested in some parts from it, or buying the whole thing.


Just took my 2003 boxster base 65k miles into shop for rear main and LN IMS $2450.00 Hope ill be happy


car runs likes a top. I was losing 1 cup of oil between 5k oil changes. decided to change out IMS with a LN replacement since I had to have motor torn down for rear main. Smart move?

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I paid a lot less for mine, but the peace of mind is worth it at any price, (almost). 1 cup or 8 ounces in 5k miles is perfectly normal oil consumption. Doesn't justify replacing the rear main seal if it's not leaking. Your engine runs like a top? then don't fix it!


Smitty your allowed to have your opion. The failure of these bearings seem to be from lack of lubrication. Th DOF style IMS setup provides constant filtered oil directly into the bearing as the car is running, that in my mind seems to be a good peace of mind in my opion. Although ive read many stories of IMS failure with different Bearing single/double ceremic/steel, oils and oil types, high and low mileage, casual driving and spirited as well and it always seems to com back to lack of lubrication. Im not saying your wrong either there could be failure with the DOF style as well. I just hope to see a correct fix so these amazing cars stay reliable and last like they should. In the mean time heres a video link for Smitty or anyone whos interested in the IMS bearing: https://www.youtube.com/watch?v=qj06dqBk0to


Hey Michael, Explain to me and the other readers how a SEALED bearing can be lubricated with pressurized oil. Porsche OEM are sealed bearings. And that's the problem. Being sealed they never get fresh oil, either pressurized or an oil bath in the sump. Not opinion, FACT. Thats why you have to replace your sealed bearing with an open cage set- up, preferably the ceramic type. The sump provides plenty of lubrication, no need to risk a pressurized leak.

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Its an open bearing that oil flows through providing lubrication. If it was sealed there would be no oil flow through the bearing you see. Sealed units burn up due to lack of oil. The great thing is you can use any type of bearing you want ceramic/steel and take that chance if you want. Im going to post this last video link that shows the correct fix for the IMS issue. Watch it and let me know what you think: https://www.youtube.com/watch?v=MCqiYU9uU1Y

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The history of the IMS video: https://www.youtube.com/watch?v=hzUq2DFpeKw

1 out of 1 people think this is helpful.

Hi Michael, I checked out your link and found it very interesting. So you're saying to replace the sealed bearings with open cage bearings and utilize an oil squirt set up that squirts oil directly into the cage. Should work, I like it. I've already converted my 996 to a twin row ceramic set-up. I'll just have to run an extra quart of oil to get more submergence in the meantime. Exposing a high pressure oil line at the bottom of the engine is risky, as one stone will break the line. Maybe someone should engineer a shield to protect it. Thanks for the link, and especially Pedro at Pedro's garage for a great bit of detective work.


Smitty Im just happy to see your just as passoinate about these cars as I am. Ive been researching this for a few years in preperation for my next Pcar purchase so I can have a good plan and know what to look for. Theres still lots of info and reasearch to do on this IMS issue and Im sure this will be one of many post about IMS failures. Have a great weekend everyone!

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