[stobbie]

over 130000 miles on my 1999 996 Carrera convertible. Never been serviced by specialists, just diy oils and filter changes. Not have had any problems yet. Most of the time I shift at 5000 RPM but it gets revved to the red every week a few times for short moments.
My first minor problem has developped now, I've got a small oil leak, it drips on the exhaust so will have to investigat the cause.
I live in the Nethelands, but have a US-spec car...

[Cicerosecundus]

Early 2001 C4 with the double race IRS bearing assembly. At 95K miles did the clutch (first time) and at the same time replaced the factory IRS bearing assembly with the double race version created by LN Engineering and put in the latest RMS. The factory bearing assembly showed no substantial wear on the bearings, but the engine side seal showed some breakdown, which would have in time led to a leak of engine oil into the bearing assembly with the possibility of bearing failure due to incompatibility between engine oil and the "permanent" grease that Porsche uses inside the bearing assembly. Also put in the LN Engineering 160 degree thermostat. Results: engine runs fabulously well and I do not have nightmares of IRS failure and an engine replacement. Also, with the low temp thermostat, when the C4 is at speed on a highway, the temperature that shows on the temperature gauge is substantially cooler then before. When I get into bumper to bumper traffic, the engine heats up as always. I have ordered a fan controller that when installed will let me program the two fans to come on at a lower temperature and to switch to high at a lower temperature and to stay on for a short period if the engine is heated beyond a particular temperature. My suggestions for taking care of this engine:
1. Never lug it: drop a gear or two if going uphill, even on the highway.
2. Do not leave your P car locked in a garage all Winter - the seals dry out and are damaged.
3. Never go over 3K RPM when warming up the engine and never warm it up at idle.
4. Change oil more frequently than Porsche recommends: I do mine at 5K miles and do three changes to equal one factory change at 15K miles.
5. Do the LN Engineering IRS bearing assembly replacement and replace an older RMS with the newest.
Thats it. I understand that there are far fewer engines needing replacement in Europe compared to North America. My explanation is that in Europe a P car is a daily driver year round - it would be unusual in Germany to leave a Porsche parked in a garage for the entire Winter and in good weather to only use it on weekends and at that, when it does not rain.
Cicerosecundus

[Wayne R. Dempsey]

I just posted a similar article on our site: http://www.pelicanpa...ne_Failures.htm

It contains some updated information from Jim's article...

Enjoy!

-Wayne

[Rennsource]

@Wayne

Thanks for posting the article here. 1) Rumor has it that the IMS issue is much more rare on 996 tiptronics - your thoughts? 2) Are you going to do a 101 projects for the 996?

pete

[rb101]

Wayne,
There are some errors in the boxster tech article #16:

photo 15:
There are three externally accessible chain tensioners on the Boxster motor. The one shown here tensions the chain between the crankshaft and the intermediate shaft and is by far the most difficult to reach. It’s located underneath the air conditioning compressor, inside the cylinder head, and is accessible from inside the engine compartment. In order to loosen this tensioner, you need to remove the two screws that hold on the air conditioning compressor and nudge it out of the way. Then use a 32mm socket to loosen the tensioner as shown in the inset photo in the lower right. You loosen the tensioner in order to replace the intermediate shaft bearing (see Pelican Technical Article: Intermediate Shaft Bearing Replacement and Upgrade (IMS)).

The picture is the adjuster for 4-6 underneath the A/C compressor

photo 16 :
This photo shows the chain tensioner for cylinders 1-3, which is located inside the bottom of the cylinder head. The three tensioners are all different, but look remarkably similar. Porsche marked the top of each tensioner with different rings in order to help distinguish amongst them. A- The main intermediate shaft tensioner located under the air conditioning compressor. B- The chain tensioner for cylinders 4-6, which fits inside the crankcase near the flywheel. C- The chain tensioner for cylinders 1-3, which fits into the bottom of the cylinder head. Note the handy marking on the head itself (purple arrow).
IMS adjuster is by the flywheel
1-3 is on the bottom of the 1-3 head
4-6 is on top the head under the A/C compressor

photo 17:
This photo shows the tensioner for cylinders 4-6, which is located on the left side of the engine case very close to the bottom of the flywheel. When replacing the intermediate shaft bearing, loosen the tensioner as shown in the inset photo. If the tensioners are leaking, you should replace the metal sealing ring (orange arrow, PN: 900-123-147-30) and the small o-ring on the tensioner shaft (purple arrow, PN: 999-707-344-40).
This is picture of IMS adjuster

[txhokie4life]

Came across this on another site -- the picture is worth the link if nothing else

IMS Issue Caught at last moment

Mike

[Wayne R. Dempsey]

You're right rb101, I flubbed those descriptions somehow. Also got by a bunch of editors too! Thanks for the note, I have corrected the article!

-Wayne

[Wayne R. Dempsey]

Rennsource, on May 13, 2010 - 05:46 PM, said:

@Wayne

Thanks for posting the article here. 1) Rumor has it that the IMS issue is much more rare on 996 tiptronics - your thoughts? 2) Are you going to do a 101 projects for the 996?

pete

The tips do seem to reduce the problems for some reason. Perhaps its because of additional water cooling?

Yes, I am working on 101 for the 996, it should be out in 2011!

Thx,

Wayne

[Heidster]

I just had a clutch replaced on my '99 996 C2 - 6 speed. FYI my car was an early build from Jan 1998 so the engine should have exploded by now...statistically speaking. @ only ~48K mi (without warning) the clutch pedal had a funny vibration and seemed too easy to push and slow to release. It also didn't have a reliable "catch point". It ended up being some bent fingers that was causing the disc to be at a slight angle in catch and release. There was not that much left material-wise on the clutch either. I was a bit surprised as I thought I'd get ~100K.

The real reason for this post is the original RMS was in fine shape (but replaced with the latest) and never leaked and the IMS bearing was replaced with an LN retrofit bearing. The original bearing was in almost perfect condition. Seal was intact, could not feel any play. I had an oil analysis done last year with all the readings normal. I'd say for ~$20 it might catch metals from the bearing and give you a warning before it fails.

But...I will sleep better. Or at least another 60,000 miles for this clutch.

This post has been edited by Heidster: July 19, 2010 - 03:48 PM

[johnnyreb2010]

earlyapex, on September 27, 2005 - 05:29 AM, said:

This reaffirms what the air cooled masses don't want to hear. The water cooled 996 motors are very reliable and cheap in the long run to own. Is is still a Porsche if the motor doesn't need to be taken apart every once and awhile? They quickly overlook the fact that air cooled engines are not cheap to rebuild. Ask me how it felt dropping off a big check to my mechanic for my 3.0 L engine rebuild. I lost a cylinder at 105,000 miles. I could buy a M96-03 engine for the same amount of money.

i own a 02 996 & have been looking for a 97 or 98 993, i love the older widebody look, my friend which owns one said the motor in a 993 will last forever, VERY SELDOM will one blow up, but when he told me what it costs to repair one, well i'm not looking quite as hard now, when i bought my porsche 2 years ago, i wasn't really lookin for any certain model, little did i know AFTER i bought it than it wasn't a REAL porsche, but i looked & looked, & i couldn't see paying as much or more for the older models when the interiors weren't nearly as nice, they didn't have reliable cold air, the ride itself wasn't as nice, so thats why i bought the 02, actually when i saw it i didn't even know it was a porsche, didn't really look like what i thought a porsche was suppose to, definitely didn't like the plain ol look, had to add some mods & then i didn't know the 997 was suppose to be alot better car, oh & i didn't really notice the headlights at the time, guess when i went lookin i didn't do my homework on porsches. but i did like the 996 because it had 320 hp, i didn't realize the older porsches didn't have much hp, except turbos, i mean you think of porsche i thought that meant bad *** cars, i guess it just depends what your lookin for in a car. if motor does blow, whats this i hear about puttin the LS vette motors in a porsche, i guess thats a BIG no-no in the porsche world.

[jthailer]

Johhnyreb,

Take your car to a PCA track event. You will have a whole new appreciation for what your car car do. It is not all about HP. HP is great in a straight line after that it is all about handling and braking ability.