Reliability of 996 Engines

[jorge61]

Interesting thread on the "reliability" of the 996 engine. I have owned several Porches in my days and currently drive daily a 04 996 C4S. We all desire reliability even though some of us drive the living hell out of these engines shamelessly. I too desire longevity and reliability and usually follow the following guidelines. Never drive the car below 2000 RPM's and shift at 3000 RPM's when cold (below 180 Temp) and 4000 RPM's once warm. This is for everyday driving in most conditions and I will open her up to 5000-6000 RPM's occasionally to get the lungs breathing properly. This has worked well for me since new and my 996 has performed flawlessly. In looking at objective data pick up the Consumer Report Used Car Guide and you will see some interesting data regarding the 04 996. It is a consumer report "recommended" model year for reliability based on all the parameters reviewed. Not bad for a Porche.

Jorge

[bmohr]

well stated jorge. Just hit the 120k mark.

Edited October 21, 2009 by bmohr

[nghiaho58]

Interesting thread on the "reliability" of the 996 engine. I have owned several Porches in my days and currently drive daily a 04 996 C4S. We all desire reliability even though some of us drive the living hell out of these engines shamelessly. I too desire longevity and reliability and usually follow the following guidelines. Never drive the car below 2000 RPM's and shift at 3000 RPM's when cold (below 180 Temp) and 4000 RPM's once warm. This is for everyday driving in most conditions and I will open her up to 5000-6000 RPM's occasionally to get the lungs breathing properly. This has worked well for me since new and my 996 has performed flawlessly. In looking at objective data pick up the Consumer Report Used Car Guide and you will see some interesting data regarding the 04 996. It is a consumer report "recommended" model year for reliability based on all the parameters reviewed. Not bad for a Porche.

Jorge

So, this is how I understand your guideline:

1. Never drive the car below 2000 RPM's.

2. Shift at 3000 RPM when cold and 4000 RPM's when warm.

3. Once awhile drive at 5000 - 6000 RPM's (watch for cop) or rev it up to 5000-6000? If revving then how long to keep it at 5000-6000 RPM's.

This is really interesting guideline. One of the Porsche Tech told me that don't drive the Porsche like a Camry or Accord. Drive it hard (not like racing) and occasionally drive it at 5000-6000 RPM's, of course at an open road and no CHP arround. This will make the car more reliable because this is the way the car was designed.

And based on this thread I see daily driving Porsches are more reliable than the low miles Porsches, especially the ones has mileage between 40K -50K.

MY is 2000 C2 and has new engine/cluth at 47K miles. It is now has 57K miles and I am driving it hard when ever I have a chance. :D

Thanks for the guideline.

:cheers:

[jorge61]

Old habits die hard, especially if you have good results. Twice a year I put injector cleaner in the engine and run the car the following way. After the car is warmed up (180 temp) I run the RPM's to 4000 and keep them at 4000 for two minutes, afterwards I run to 5000 RPM's for one minute and lastly I run to 6000 RPM's in every gear possible for the last part of the workout. This is not a track car so I do this to give the Porche a good workout. For those folks that track their Porches I see no benefit to this routine (they have other problems to deal with). Porches love to be driven continuously and methodically. I firmly believe if you take care of them they take care of you. ($$$)

Jorge

[nghiaho58]

Old habits die hard, especially if you have good results. Twice a year I put injector cleaner in the engine and run the car the following way. After the car is warmed up (180 temp) I run the RPM's to 4000 and keep them at 4000 for two minutes, afterwards I run to 5000 RPM's for one minute and lastly I run to 6000 RPM's in every gear possible for the last part of the workout. This is not a track car so I do this to give the Porche a good workout. For those folks that track their Porches I see no benefit to this routine (they have other problems to deal with). Porches love to be driven continuously and methodically. I firmly believe if you take care of them they take care of you. ($$$)

Jorge

What kind of injector cleaner do you use? I am afraid of using the none OEM (not Porsche approved) brand which may cause more damage than good.

Thanks!

[jorge61]

Old habits die hard, especially if you have good results. Twice a year I put injector cleaner in the engine and run the car the following way. After the car is warmed up (180 temp) I run the RPM's to 4000 and keep them at 4000 for two minutes, afterwards I run to 5000 RPM's for one minute and lastly I run to 6000 RPM's in every gear possible for the last part of the workout. This is not a track car so I do this to give the Porche a good workout. For those folks that track their Porches I see no benefit to this routine (they have other problems to deal with). Porches love to be driven continuously and methodically. I firmly believe if you take care of them they take care of you. ($$$)

Jorge

What kind of injector cleaner do you use? I am afraid of using the none OEM (not Porsche approved) brand which may cause more damage than good.

Thanks!

I usually use STP or Chevron Techron. I am not aware Porche sell's approved fuel injector cleaner. It's an engine not silly putty.

[lovely09]

Very useful article.I more understand how everything works with the engine.Giving a preview makes the reader learn more of reliability.

[libbi78]

Hello all,

This is my first post in the forum. I recently purchased a 2000 996 with 111K on it. Since I am a dealer, I was able to pull all service records, etc, from Porsche and found (before purchasing) that no major problems occurred with the vehicle since new. Oil changes were done at the very least, every 5000 miles and all scheduled maintenance was completed. After purchasing the vehicle, I drove it TWO MILES before I heard a pop followed by large bellows of smoke from the exhaust. I took it to the local Porsche dealer where they diagnosed a failed oil cooler. After replacing the oil cooler and flushing the engine and cooling components, I drove the car home. After driving 143 miles, I noticed my coolant level dropping and my oil level increasing in addition to it being a milky white cooler. There was oil in the coolant reservoir as well. Both the compression AND leakdown tests were perfect. Any ideas as to what may be causing this? Thank you!

[txhokie4life]

Hello all,

This is my first post in the forum. I recently purchased a 2000 996 with 111K on it. Since I am a dealer, I was able to pull all service records, etc, from Porsche and found (before purchasing) that no major problems occurred with the vehicle since new. Oil changes were done at the very least, every 5000 miles and all scheduled maintenance was completed. After purchasing the vehicle, I drove it TWO MILES before I heard a pop followed by large bellows of smoke from the exhaust. I took it to the local Porsche dealer where they diagnosed a failed oil cooler. After replacing the oil cooler and flushing the engine and cooling components, I drove the car home. After driving 143 miles, I noticed my coolant level dropping and my oil level increasing in addition to it being a milky white cooler. There was oil in the coolant reservoir as well. Both the compression AND leakdown tests were perfect. Any ideas as to what may be causing this? Thank you!

Possibly a blown cylinder head freeze plug? unfortunately I bough it that way so I can't tell you what it sounded like at the time of failure.

I've got a pointer to a whole rebuild of my Boxster S due to that. (search this forum)

the root cause was a broken water pump.

mike

[FredL]

Hello all,

This is my first post in the forum. I recently purchased a 2000 996 with 111K on it. Since I am a dealer, I was able to pull all service records, etc, from Porsche and found (before purchasing) that no major problems occurred with the vehicle since new. Oil changes were done at the very least, every 5000 miles and all scheduled maintenance was completed. After purchasing the vehicle, I drove it TWO MILES before I heard a pop followed by large bellows of smoke from the exhaust. I took it to the local Porsche dealer where they diagnosed a failed oil cooler. After replacing the oil cooler and flushing the engine and cooling components, I drove the car home. After driving 143 miles, I noticed my coolant level dropping and my oil level increasing in addition to it being a milky white cooler. There was oil in the coolant reservoir as well. Both the compression AND leakdown tests were perfect. Any ideas as to what may be causing this? Thank you!

Wow, I thought I was reading about my 2000 C4 with 81k miles. I had the same problem, failed oil separater, reduced coolant, increased oil level, oozing coffee color fluid. I had the cracked cylinder wall problem. :cursing: $16,000 later I had a rebuilt engine installed. :angry: Odd thing, the original engine did not use much oil at all, the rebuilt engine uses more oil. I hope it lasts. I am disapointed with the 996 engine.

[c70Pete]

Hello all,

This is my first post in the forum. I recently purchased a 2000 996 with 111K on it. Since I am a dealer, I was able to pull all service records, etc, from Porsche and found (before purchasing) that no major problems occurred with the vehicle since new. Oil changes were done at the very least, every 5000 miles and all scheduled maintenance was completed. After purchasing the vehicle, I drove it TWO MILES before I heard a pop followed by large bellows of smoke from the exhaust. I took it to the local Porsche dealer where they diagnosed a failed oil cooler. After replacing the oil cooler and flushing the engine and cooling components, I drove the car home. After driving 143 miles, I noticed my coolant level dropping and my oil level increasing in addition to it being a milky white cooler. There was oil in the coolant reservoir as well. Both the compression AND leakdown tests were perfect. Any ideas as to what may be causing this? Thank you!

Wow, I thought I was reading about my 2000 C4 with 81k miles. I had the same problem, failed oil separater, reduced coolant, increased oil level, oozing coffee color fluid. I had the cracked cylinder wall problem. :cursing: $16,000 later I had a rebuilt engine installed. :angry: Odd thing, the original engine did not use much oil at all, the rebuilt engine uses more oil. I hope it lasts. I am disapointed with the 996 engine.

The safe way to go here is a 3.6 motor that you have reliable service history on and Jake Raby's IMS update... the 3.6 and 3.4 engines have their gremlins but I think the 3.6 engines are stronger with the exception of their IMS shaft... more IMS failures on 3.6 than 3.4 motors... even if I bought a used 3.6 996 I would drop tranny and replace the shaft via Jake's retrofit kit... a must with the 3.6 cars.... the 3.4 cars... its a pure gamble due to cylinder wall failures and cracked cylinder head potential...

[Dennis C]

Just about to roll 89,000 miles. Had it in for the 90,000 mile service last week. I also had the throttle body cleaned. It still runs great, still doesn't burn oil. It's a great daily driver.

[hoacha]

Hello folks.. I am the new guy here. I have 143,000km on my 2002 C4S without any major problems.. Is there anything to extend the life of the motor( RMS and Int shaft in particular) that I could do , other than regular service?. Maybe a thick oil other than 0W40 ? Thanks!!

[thesandman]

Hello all,

This is my first post in the forum. I recently purchased a 2000 996 with 111K on it. Since I am a dealer, I was able to pull all service records, etc, from Porsche and found (before purchasing) that no major problems occurred with the vehicle since new. Oil changes were done at the very least, every 5000 miles and all scheduled maintenance was completed. After purchasing the vehicle, I drove it TWO MILES before I heard a pop followed by large bellows of smoke from the exhaust. I took it to the local Porsche dealer where they diagnosed a failed oil cooler. After replacing the oil cooler and flushing the engine and cooling components, I drove the car home. After driving 143 miles, I noticed my coolant level dropping and my oil level increasing in addition to it being a milky white cooler. There was oil in the coolant reservoir as well. Both the compression AND leakdown tests were perfect. Any ideas as to what may be causing this? Thank you!

Wow, I thought I was reading about my 2000 C4 with 81k miles. I had the same problem, failed oil separater, reduced coolant, increased oil level, oozing coffee color fluid. I had the cracked cylinder wall problem. :cursing: $16,000 later I had a rebuilt engine installed. :angry: Odd thing, the original engine did not use much oil at all, the rebuilt engine uses more oil. I hope it lasts. I am disapointed with the 996 engine.

The safe way to go here is a 3.6 motor that you have reliable service history on and Jake Raby's IMS update... the 3.6 and 3.4 engines have their gremlins but I think the 3.6 engines are stronger with the exception of their IMS shaft... more IMS failures on 3.6 than 3.4 motors... even if I bought a used 3.6 996 I would drop tranny and replace the shaft via Jake's retrofit kit... a must with the 3.6 cars.... the 3.4 cars... its a pure gamble due to cylinder wall failures and cracked cylinder head potential...

Wow, please excuse my ignorance, but that sounds very aggressive to me for preventative maintenance. What would such a retrofit cost installed? Does this guarantee no IMS failures?

[Dharn55]

The cost of the LN IMS bearing upgrade is $595, and about $70 for the tool. Another $1,000-$1500 in labor if you don't do it yourself.

[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.pelicanparts.com/techarticles/Boxster_Tech/13-ENGINE-Common_Engine_Failures/13-ENGINE-Common_Engine_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]

@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.

Edited July 19, 2010 by Heidster

[johnnyreb2010]

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.