Problem Areas

All cars have problem areas, Boxsters are not exempt.

Do not overreact to this list. You have more (and more honest) information here than you will probably ever see about a car.  So a comparison of your impression of the reliability of a Boxster after reading this list, to some other car where you didn't have such information would be very unfair to the Boxster.  Perhaps most telling of my feelings is that I know all this and I bought a second Boxster and when I did, I declined an extended warranty!  My experience with owning a Boxster has been exceptionally good compared to my experiences with other cars my family has owned during the same period (Mazda, Honda and Acura, Dodge and VW brands).  

My 2 Boxsters have never failed to start or left me stranded. I think non-scheduled maintenance costs over 5 years have averaged $12 a month for the Boxster.  

Specifically, my first Boxster (a '99) experienced none of these problems.  My second Boxster (an '01S) experienced problem #6 (RMS) below which was fixed while under warranty for a previous owner.  During my ownership, it has experienced problems #7 (Airbag Light) 4 times, #10 (tired O2 sensor) and #11 (air induction loose connection). Not bad for 5+ years on a 10 year old car.

Not all Boxsters will have all problems, especially the first two which are limited to very early production and which, while serious, Porsche has owned up to.

The color code for these is:

  Red: You need to replace the engine or get it rebuilt for $$$$$.

  Blue: Enough to temporarily disable the car but generally not long term fatal if dealt with promptly/correctly.

  Black: Just annoying

1. Porous Block Early '97 engines had a "porous block" problem that generally massively failed within the first 10k.  All are thought to have been replaced by now. The best description of this problem I know of is here.

2. Slipped Sleeve Mid '98 thru early '99 engines had major internal engine slipped sleeve problems that would cause total engine failure. Porsche replaced all the engines that experienced the slipped sleeve problem under warranty (and many after warranty).  A replaced engine is a good thing as the replacement engines have actually been more thoroughly tested than the ones put directly into new cars. The best description of this problem I know of is here.  I know of nowhere where it lists a manufactured-after date or an engine serial number after which the problem was corrected so that you could know the problem will not affect a specific car.

3. IMS (Intermediate Shaft) bearing failure can affect all 986 Boxsters model years though with varying and unknown frequencies. This is an internal engine failure and can result in the need to replace the engine. There is an expensive parts replacement that is available but not from Porsche and not warranted by Porsche (and many dealers won't install it).

Not all engines will experience the problem. Many Boxster engines are still running with their original bearings at 100k-200k miles. There is no way of knowing the frequency as no one has a large enough sample to be statistically valid except for Porsche and they aren't telling for legal reasons.  There are wildly varying estimates flying all over the forums, all of which should be viewed skeptically. 

As there were three versions of the IMS bearing, a general understanding is that the third generation is much better than the second which is worse than the first.

The probable sequence of events is thought to be caused by a deterioration of the inner seal that protects the bearing from oil in the block. Since the bearing is designed to be lifetime lubricated by grease, when oil from inside the engine penetrates beyond the inner seal and gets into the grease, the hot oil melts the grease and gradually replaces the grease with oil.  Depending on how clean the oil is and how successful the oil is in penetrating the inner seal with regularity, the oil can lube the bearing successfully or not. If not, the bearing wears and gradually the IMS shaft begins to wobble. This can cause the chains which drive the engine internals like the camshafts to jump a tooth on the sprocket on the end of the shaft and that leads to massive internal engine failure due to valve clash with the pistons. This causation theory is supported by pictures of IMS bearings, that, when removed as a preventative measure, are worn, wobble, have no grease in them or just badly deteriorated oil.

There can be a warning of a grinding sound which comes very shortly before the failure or there may not be. There can be camshaft deviation which can be detected with the proper equipment. There can be metal "shavings" from the ball bearings that can be detected by a "Detector" (see LNengineering).

Some say cars driven under high rev'ing street or track conditions and with frequent oil changes suffer less from this problem.  Cleaner oil sloshed around so the clean oil gets into the bearing and keeps it lubricated is the theory. Some say that cars with the automatic transmission (TIP) suffer less from this problem.  Other say that, because the TIP shifts into a higher gear quicker than most people manually shift, there is less oil splashed up against the seal within the block and so, when the seal fails, there is less oil penetrating the bearing so the bearing wears quicker and failure is more likely. Another observation is that cars used for short trips or stored with dirty oil (both of which allow condensation in the crankcase) may allow water into the bearing and rust to form creating a rough spot on the bearing which then contributes to more rapid wear.

This problem has been covered in detail in the June and August 2010 issues of Excellence magazine. The current preventative solution is from LNengineering.  They offers a much better bearing than the Porsche bearing and without the inner seal so it is  lubricated by the engine oil splashing around in the crankcase. Pelican offers a kit which uses a bearing of the original type with an inner seal of the same materials as Porsche used. Hartech in the UK installs an original bearing while omitting the inner seal and using the oil splash approach. There is also a bearing replacement for certain bearings which eliminates the ball bearings entirely and substitutes a bearing made of the same material used in the bearing on the other end of the Intermediate Shaft.  This is lubed with filtered  and pressurized oil. This is (as of January 2013...things evolve so it is best to go to the web site of the supplier for the latest updates) only available thru flat6 and has at least a three month waiting line. It is also expensive. But it is said to never need replacement.

Fixing this problem involves removing the transmission from the engine for access to the rear of the engine and removing the cover, seals and bearing and replacing them. I've heard of costs ranging from $1,000 to $3,000+ quoted with that for a Tiptronic auto-manual trans the more expensive.  You want someone who has done it before to do the job.  References are available from those who sell the bearing. They are most economically installed when a clutch is replaced or the transmission is removed for some other reason. 

If it happens, don't drive the car. Get the car flatbedded.

Porsche will cover this repair and replace the original engine if the car is within warranty.  On line reports in '10 are that Porsche is only helping in out of warranty situations where this occurs if the car is owned by the original buyer, the maintenance is up to date and the maintenance is all done by the selling dealer, the claim is done through the selling dealer and the mileage is low enough (exact limits unknown). (Or the owner has a long history of buying Porsches!)  Other claims seemingly are denied.  There have been several reported cars which have had multiple failures on different engines so there may be a connection between driving style and maintenance frequency and the failures.  Or it may just be statistical probability.

This is the one design issue that most concerns potential buyers and owners and where there is general feeling that Porsche should stand behind their product even for cars out of warranty.  There are third party replacements engineered to fix the problem available here but even the provider of the improved bearing, seal and lubrication method recommends replacing the IMS bearing no matter its source at around 50k miles (though that may prove to be unnecessary after more bearings are pulled and examined.)

Something to consider when looking for a 987 is the difference in the IMS between the early '05 and late '05-'08 models. As you may want to replace the IMS when/if you redo the clutch or when you redo the RMS, the model year does make a difference. The early '05 is a fairly easy/cheap redo of the IMS bearing compared to the late 05-'08 model which requires a $$$$ removal of the engine, a split of the case and replacement of the entire IMS shaft! You might as well rebuild the engine entirely while you are in there.

And to compound the problem, if your car has a replacement engine, it could have any of three kinds of Intermediate Shaft designs and you won't know for sure till the transmission is unbolted from the engine. And if you have a '05 engine, you can't be sure which IMS design Porsche used until the transmission is unbolted from the engine.

As of October-November 2011, there is a device available from which detects the metal particles being shed as the bearing deteriorates and triggers an alarm that tells you to immediately get the bearing assembly replaced. This device is the subject of a Tech Notes article in Excellence magazine, November 2011 edition.

There is a great deal of online discussion in Boxster forums about this problem. Some of the angst and "statistics" are driven by those who have a financial interest in solutions.  The truth is there are no valid statistics.  All mechanical parts which rub against another wear. Some wear out faster than others even if they both were installed the same day in a similar engine. All cars, all parts.

Additionally, there was a class action lawsuit settled in April of 2013 where Porsche admitted to a 10% failure rate on the second design of the IMS bearing (2000-2004+) and offered some compensation. Details are available by searching for the word "settlement" on Rennlist.comin either the 996 or Boxster forums.

4. D-Chunk is the failure of the cylinder liner sleeve which fractures and a D-shaped piece separates from the end of the sleeve.  It is thought to be made more probable by not allowing the car to thoroughly warm up to operating temperature before driving off.  Sharp increases in this problem are reported in the cold months. It is least common in 3.2 litre engines.

5.  AOS  "The air/oil separator is essentially what was called a crankcase breather hose in earlier days. It's simply a vent from the crankcase to the intake. In the past, the crankcase was simply vented to the atmosphere releasing any volatile pollutants directly into the air. Nowadays, the crankcase volatiles are vented to the intake where they are burned in the cylinders. It's a hydrocarbon emissions reducing measure. To reduce the sheer amount of oil that gets drawn into the intake, they developed the air/oil separator which is designed to condense the higher boiling components and the oil mist (very fine droplets of oil that form when warm oil is mechanically whipped up continuously like it is inside the engine) and allow it to drain back into the crankcase.

There are two "failures" with the air/oil separators that I can distinguish. The first is simply a torn accordion looking tube (sometimes referred to as the "bellows tube") that goes from the crankcase to the bottom of the separator. This causes an oil leak and also a vacuum leak to the intake. The vacuum leak to the intake causes a lean running condition, which the ECU detects and adjusts to by enriching the mixture. Ultimately, the ECU maxes out its enriching ability and triggers a check engine light with the fault codes associated with enrichment limit: P1124, P1126, P1128, and/or P1130. (Note that this end result is general for any intake vacuum leak, not just the that caused by a torn AOS tube.)

The other failure mode is the failure of the air/oil separating ability of the separator. I don't know the exact nature of what happens in this case since I've never disassembled an air/oil separator. When this happens large amounts of oil can get sucked into the intake causing major oil smoke from the tailpipe. If this is allowed to go on long enough, spark plugs will become fouled, and I believe the catalytic converters could be permanently damaged. In the worst case scenario a cylinder could even fill up with enough oil to cause a condition known as "hydraulic lock" in which the piston now tries to compress an incompressible fluid in the cylinder on the compression stroke. The oil can't be compressed so something has to give, and kablooie... big problems." 

the above contributed by Brett from San Diego

Symptoms of AOS failure are typically huge oil clouds on startup or under hard acceleration, braking or cornering. Replacing the AOS  can be a ~$120 Do It Yourself that takes several hours.  It is more dirty work than smart work and anyone can do it.  Instructions are on this site.  There is a racing AOS from the GT3 that can be fitted that is said to be more robust but it is much more costly and is not a direct fit.

4.  Heat Exchanger  "The oil/water heat exchanger is simply a radiator-like device with oil and coolant flowing through separate but intimately contacting channels. When the engine is just warming up, the coolant will be warmer than the oil, so the coolant will transfer heat to the oil to help warm the oil faster. When the engine is at operating temp, the coolant will be colder than the oil, so the coolant will take heat away from the oil.

Reported failures of this part are rare, but it has been reported. If the internal passages fail, the oil and coolant will mix resulting in the appearance of a head gasket failure, when actually the problem is much cheaper to correct by simply replacing the oil/water heat exchanger (and of course flushing and replenishing the coolant and oil systems)."   

 contributed by Brett from San Diego

The exchanger for the S model is larger than the one for the base model Boxster and so can be used as a replacement/improvement.

6.  RMS (Rear Main Seal) wear exhibits itself as an oil drip. Attributed to the design of the crankshaft and its supporting structure as well as poorly designed seals. Porsche has provided at least 3 generations of parts and fix procedures. Said to be more common in stick shift models than in Tiptronic-equipped cars. About $1000 to repair. Repair consists of measuring the crankshaft hole and, if it is within specs, just replacing the seal with a new seal. If it is outside specs (crankshaft wobbles in the hole), then the suggested repair is engine replacement. You shouldn't pay for this yourself, it is a design flaw.  Insist nicely but firmly your dealer contact Porsche.

Some cars have experienced multiple RMS problems. Porsche has replaced some of the engines in such cars and in cars where their measurement tool says replacement is the only option. Even out of warranty, they will sometimes buy the engine if you pay the labor.

Porsche has gone through 3 generations of seals. The newest one seems to be a successful fix.

7.  Airbag Light Early Boxsters have a problem with seatbelt buckles not being grounded properly and causing an airbag light to be triggered. Replacement of the seatbelt or repair of the ground is the corrective action. There is a TSB #692450102.80TU and there is some chance that that TSB has been replaced with another one sometime in 2006.  This can be a re-occurring problem, mine has been to the dealers 4 times with this symptom.  For the last 4 years it appears to be fixed using the new procedure.

8. Top Cables Early Boxsters ('97-'99) have problems with the cables which operate the top frequently failing. Replacing with the newer style cables fixes the problem and is a do it yourself item. Instructions are available.

9. MAF Like almost all modern cars, the Boxster has a Mass Air Flow Sensor (MAF) in the air intake between the air cleaner and the engine that reports the amount and temperature of the air to the Engine Control Unit (ECU). The sensing surfaces of the MAF can get dirty.  When that happens or when the MAF fails, the ECU detects bad or missing signals from the MAF and throws a Check Engine Light up on the instrument display.  How to clean it yourself in less than an hour for a total cost of about $30 (and save up to $690) is covered here.  You can replace it with the OEM part even if you aren't an expert mechanic.  Often changed out even though the problem is something else like an intake air leak.  Run through the complete diagnosis flow chart before spending the money to replace the MAF.

10. O2 Sensors sit in the exhaust air stream and signal the ECU how it should adjust the air fuel mixture to achieve clean exhaust gases during startup. Depending on the model year, Boxsters have either 2 or 4 sensors. They wear out on any car as they sit in the dirty exhaust flow.  If it is just an O2 sensor going bad, they give off a very specific code and can be easily and cheaply replaced by a do-it-yourselfer from instructions here.  Or many muffler shops will do it for you if you bring the right part.  No reason to visit the dealers or buy the Porsche-branded part.  Generally occurs around 50-75k miles. Typical of any modern car. My Honda and Boxster failed the same week. The Porsche part was cheaper, the labor the same.

11. Supplementary Air Induction, etc. The Porsche Boxster engine uses complicated engine management sensors and electronics to achieve acceptable emissions, as do all modern cars.  Problems in this area throw a Check Engine Light (CEL) onto the instrument display.  Diagnosing what is wrong can get complicated and is best done with a Porsche System Tester 2 (PST2) or PWIS and other specialized tools and access to the Porsche multi-volume Maintenance and Diagnostic Manuals.  This area includes sensors, valves, tubing, blowers, etc.

12. Ignition Switch  The ignition switch is prone to mechanical failure.  It can be replaced with a $20 Audi part by a do it yourselfer who is young and supple. The dealers want several hours of labor and they are entitled to it as the job involves getting under the dashboard upside down and removing two screws that are devilishly hard to get at.  Someone who is limber and has done it several times can do it in 15 minutes.  I've read speculation that this is caused by too many heavy keys on the keychain.

13. Engine Mount  The "rubber" portion of the front engine mount deteriorates over time.  An improved part is available (PCA members get a discount at most dealers) and a do it yourself if you have access to a lift and the right tools or are exceptionally young and limber.  Symptoms are usually a clunk when shifting or a change in the effort of moving the shift lever when shifting.

14. CVS boots on the axle shafts of 6-speed Boxsters rip with some frequency and, when this happens, dirt and water can penetrate to the bearings, wear can occur and a half shaft replacement can be needed. Inspect and repair the rubber boots frequently if you have a 6-speed. The 5-speed and Tiptronic equipped cars don't seem to be as prone to this problem as their drive shafts are at different angles than the 6-speed cars and don't put as much stress on the "rubber" covering.

15. The Location of the battery The Boxsters battery is locked away in the front trunk. And access to the front trunk can be very difficult if the battery has completely run down and there isn't enough voltage to power the motor that releases the lock. There are ways to jump the battery enough to unloose the lock or to pull an emergency cord that mechanically unlocks the trunk. This is just something you should practice ahead of time because if you ever need it, it is sure to be in the dead of night, raining cats and dogs, etc.

16. The water pump The pump uses a plastic impeller which can fail and the water flow can carry small bits of it into water passages within the head and block. This water flow blockage can result in hot spots which lead to cracks or water/oil intermix.  The current thinking is to change the water pump at about 50k miles. There is no well made reliable metal impeller replacement known.

There are fixes involving improved parts or third-party parts with improved designs available for some of these problems.

People ask me how do I feel about these issues. I reply every car design has them, we just know more about ours because we are so passionate about our cars.  Knowing these issues, I bought a second Boxster.  I continued to drive and enjoy my Boxster on short and long trips with confidence it will get me there.  It always has.

Could it fail tomorrow? Yes. And so could any car.

The other day I had to make a 50 mile each-way trip.  The remains of hurricane Ida were dumping many inches of rain per day on us and winds were gusting to 50MPH.  It was dark and the roads were 2-lane, not lighted at all.  

I had my choice of 3 cars:

  •  Acura TL with new all season tires and new brakes.
  •  Honda CRV with all-season tires well maintained
  •  My '01 Boxster S with summer tires with 15k on them and brakes with about the same.

I chose the Boxster, enjoyed the ride and I didn't even carry a cell phone. I figure that for any given trip, I'm more likely to hit a deer or have a heart attack than for my Boxster to fail me.