
How to Read Porsche Diagnostic Trouble Fault Codes
In this guide, we look at how to read and clear Porsche fault codes (also referred to as Diagnostic Trouble Codes or DTC).
Whether you are new to the Porsche world or a die-hard enthusiast, you have probably heard of the dreaded intermediate shaft bearing, or IMS, failure. This is a terrible stain on the reputation of what is otherwise beautiful, exciting, and reliable sports cars. Luckily, only a few models have any issue with this particular failure.
In fact, there are only two Porsche models affected by the IMS bearing issue:
More specifically, models such as the 996 and 986 models, produced between 1997 and 2004. However, this is not the case with high-performance models, like the turbo. If you are concerned about IMS bearings issues, read on to learn more.
First, Porsche sports cars have been traditionally powered by horizontally opposed engines commonly called boxer engines. As mentioned above, the IMS bearing issues typically impact the 911 Carrera and Boxster.
These incredible pieces of engineering work differently than normal internal combustion engines, as their pistons push outward instead of up and down, creating a very compact power unit. At the time, this was Porsche's first offering of a water-cooled boxer variant to the market. So, you may be wondering, what exactly is an IMS bearing?
The letters stand for Intermediate Shaft, a tube that runs from the front pulley side of the engine to the rear valve timing assembly. The IMS powers either three or five timing chains, depending on whether it is a first or second generation of the Porsche M96 power plant.
At the end of the tube are sprockets that drive the timing chains around the camshaft gears in the cylinder head to keep the valve assembly in time with the crankshaft. In short, the IMS bearing is the glue that holds the entire engine timing assembly together.
Unfortunately, there are not many warnings to the bearing having issues, but there are a few signs you can look out for. Here they are.
To put it bluntly, if the IMS bearing fails, so do many of your dreams. IMS failure is considered catastrophic in the mechanical world, which means it will probably never run again.
The M96 is a high interference motor, so the cylinder head to engine block timing is crucial to its operation and survival. Failure causes the timing chains to skip or even break, making the Pistons come into contact with the intake and exhaust valves, slamming into each other, breaking apart.
The oil pump then sends these chunks of metal to every corner of the engine damaging everything they come in contact with along the way. You now have a Porsche paperweight; this is the part that makes new buyers scared of these truly great cars.
If you own a 911 or Boxster with an IMS failure, you have really two options: replace the engine or sell the car for parts non-running. Refurbished engines range from around $10,000-$15,000 for a 911 and $5,000 to $8,000 for Boxsters; this does not include installation, which takes about 8 hours with a Porsche familiar technician.
Depending on your area and the shop rate, this can be from $1,000 to $2,000, not to mention all the small things like fluids, old rubber hose, plastic clips, rusty exhaust bolts, etc. and small parts that never survive engine out operations that all carry the notorious “Porsche Tax."
You can also save money by purchasing a new Porsche IMS Bearing online.
A ray of hope in this otherwise scary campfire story of what can happen when you buy the wrong car is there are many ways you can keep IMS bearing from ever being an issue. Porsche factory maintenance specifications state that the bearing should be serviced every 60,000 miles or about as often as the clutch.
If you are purchasing a car, always ask for any records the owner has to see if the bearing has been serviced properly. Make sure to get that pre-purchase inspection as well because this is not a DIY job. Special tools are required, and the engine is toast if not performed correctly. If you can not find service records available, then you should factor the cost of replacing the IMS bearing into the initial price of the car.
You have options with either factory Porsche replacement parts or several aftermarket companies that make exceptional and arguable better-designed hardware.
LN Engineering is the industry leader in these retrofit kits with much stronger roller style bearings and even “true fix” solutions that replace the IMS with an oil-fed lubricated bearing instead of the factory dry style. In any case, the IMS bearing is a wear item with long service life, so it is not something to be overly concerned about.
If you own or are in the market for a 996 Carrera or a 986 Boxster, you should not worry. These are great cars that have gotten a bad reputation for being unreliable. Porsche's IMS was partially redesigned in 2002 and completely redesigned in 2004 for the new M97 engine.
In my professional opinion, the IMS failure is mostly internet ghost stories of poorly maintained cars. This fear has driven the prices way down, which means you can enjoy a wonderful sports car at an affordable price.
By YOUCANIC Automotive Experts Published on: Thursday, January 7, 2021. |