1996-1999 Boxster IMS
 

What is the rule of thumb for 1996-1999 Boxsters and IMS? I know they are not immune but have heard that after 50k they are probably going to be trouble free? Any truth to that?
Thanks

I suggest you do some research on the 986 forum. Those years I believe that there is reduced chance of ims failure but increased chance of slipped sleeve.
Guy

There are a lot of anecdotes and there are companies pushing fear in order to sell their 'solutions.' The old term "follow the money" applies. Anecdotally, it appears the solutions could have a higher rate of failure than the original bearings. I don't know anyone collecting stats on that.

As you may know, there was a class action suit that smoked out actual statistics on the IMSb failures. I recommend you stick with sources that incorporate those statistics in the dialog.

If you go to 986 forum and do a search for poll ims related engine failure. It gives historical % of ims related engine failures for each year.
Cheers, Guy

The IMS issue is not as common as some would like you to believe.

I've found that the majority of M96 failures comes from infrequent oil changes and babying the engines. They need to be run hard and oil changes every 5-6K.

The biggest issue with IMS failures is their catastrophic nature. You're buying a new engine if it goes.

Look at the number of known issues that can cause complete destruction like that and compare the % then. Are IMS's going to failure as much as, say, a window switch? No, but window switches are not 5 figure fixes.

I own a Porsche repair shop in Ct. I've had three 96-00 Boxsters lose IMS bearings
Percentage wise it's small but if it happens to you it's 100% The repair is cheap and the car
otherwise is great so fix it forget it and enjoy the car

Yes the IMS failure can happen. From all of the research the failure rate seems to be 3-5%. The pre 2001 cars appear to have an even lower failure rate. I've decided to assume the risk with my Boxster. If there is a failure, there are plenty of good, used Boxster engines out there.

I bought my '97 with 100k miles on it. It now has 216k miles on it with the same IMS bearing. I drive it hard and don't worry about it. My bulletproof SC snapped a head stud 2 years ago with 125k miles on it.

The earlier cars (through '99 I believe) had the more robust dual-row bearing, failures of those are very rare. Failures on the 986 seem to be more rare overall than the 996, some have suggested that the M96 motor is less stressed in the 986 due to its lower power and therefore more robust.

They are fantastic cars. If you don't like the worry, replace the bearing for $800 when you do the clutch. That's not a lot of money in Porsche terms. I had a '97 with 135k on the original IMS, it was a great little car.

Thanks to all for the great advice. How do I determine if my car has the single row or double row bearing?

Pull the transmission. Or just drive the piss out of it.

Engine Number Model Bearing Type

Up to engine # M 651 12851 Boxster 2.7L M96.22 Double Row Bearing
Up to engine # M 671 11237 Boxster S 3.2L M96.21 Double Row Bearing
Up to engine # M 661 14164 Carrera 996 3.4L Double Row Bearing
From engine # M 651 12852 Boxster 2.7L M96.22 Single Row Bearing
From engine # M 651 11238 Boxster S 3.2L M96.21 Single Row Bearing
From engine # M 661 14165 Carrera 996 3.4L Single Row Bearing
All 2005 Boxster 987 (maybe some 2006 models) Single Row Bearing
All 2005 Carrera 997 (maybe some 2006 models) Single Row Bearing
Maybe some 2006 Cayman models Single Row Bearing

Read this article: Pelican Technical Article: Boxster Intermediate Shaft Bearing Replacement and Upgrade (IMS) - 986 Boxster (1997-04) - 987 Boxster (2005-06)

Small percentage of IMS failure's but THEY DO HAPPEN. Some without warning. Depending on MY, Porsche did goodwill engine replacements. Basically that was to keep a customers at bay and escalate class action issues but behind the walls saying they made errors. Time has expired on any of that so will it happen to you? For those naïve thinking there's some fear marketing for monitors or update, well that's like going without insurance. I personally have known of four having failures. Theories of why it happens vary but HIGHLY suggest reading the many informative threads here on Pelican and solutions. That's all.

I wish this was mentioned more often. Nostalgia always dictates that the old stuff was better, but every Porsche model has had it's flaws. Just think if head stud prevention were that cheap.

100% of ball bearings will wear out eventually. It's an inescapable fact. I'm only familiar with the 2006 Cayman S 3.4. Our failure alert noise happened as we had just done a brake job and were letting down the lift. The bearing inner stub on this model is 1 mm smaller than the i.d. of the IMS tube so it was riding on the stub and making god awful noises. I don't know how much clearance/support the earlier models would have. If I had an early, I'd certainly make sure the stub had a minimum clearance to the IMS tube for safety net. At high rpm, there may have been MAYHEM, but my son was able to limp it 6 miles to the home garage. SOoooooo lucky!

Other than the IMS problems, The 96-97-98 and maybe some 99's had the cylinder wall casting porosity problem and the 'D' chunk failure mode, wear a cylinder wall can crack and fall apart. Most of those engines were replaced by Porsche by now. They would rarely last long, but every now and then you would hear someone have it happen again.

By 50,000 miles, you should be clear of that.