Hei Christian
Fant litt mer info, som kanskje kan være til hjelp. På engelsk riktignok
Some of the more common failure/maintenance points:
Rear Main Seal: The C2 and C4 engine is prone to rear main seal leaks. While the internet makes it seem like a huge deal, it is not as common as one might think. It is definitely something to look for when purchasing a 996 though. Cost of replacement can typically run upwards of $1500 since you replace the clutch while you are in there. The updated seal used is a 997 part number. Typically, if the engine does not show a leak at the RMS by 15k miles, then it will not likely occur. The RMS issue does not exist in the turbos, as the engine is the traditional flat six, split case design. I am sure they still occur on occasion, but not nearly as often. When should you replace the seal? When the oil drips on the driveway start to annoy your wife. Will it hurt anything? No, but a severe leak will obviously lead to decreased oil in the engine over time, and could lead to engine failure if you do not add the oil it is losing.
Clutch: Typically clutch life will be around 50-60k miles. This will all depend on the driver of the vehicle though. I have seen clutches go out around 30k miles, and some cars with 70k miles on the original clutch. Cost to replace is roughly $1500 for C2/4. For the turbo, expect around $2500-3000 due to twice the labor rate (18 hours), and a more expensive clutch.
Stiff Clutch Pedal: Typically a very stiff clutch pedal in the C2/4 is indicative of a bad throw out bearing guide arm. There is an updated arm and release bearing which will alleviate this problem. Again, you are looking in that $1500-1600 range to have it replaced.
Tires: Porsche put quite a bit of negative camber and resultant toe into the rear suspension, and along with the weight of the engine being over the rear tires, tire life is much shorter than a standard car. Typically 15k-20k miles out of a set of rear tires is doing very well. Due to the negative camber/toe, the insides will wear out first, while the outside tread will still look good. Front tires will last longer, and typically you will get twice the life of the fronts versus the rears. You can realign the car to a more neutral toe setting in the rear and extend the life a bit.
Brakes: At roughly 30-40k miles you will probably need at least brake pads in the front. They wear almost twice as fast as the rear pads, so typically you can get a set of rears to last per 2 sets of front pads. At 60k miles, expect to replace the rotors at all corners. To replace everything front and back, expect around a $1200 bill.
Oil Changes: Typically the engines will use a Mobil 1 0w-40, 5w-40, or castrol 5w-40 full synthetic oil. Usually it will take roughly 8.5 quarts of oil, and a paper cartridge oil filter (Mahle #OC128). Some dealers will charge $60, some will charge $250 or more!.
Tune-ups: Tune ups are done every 15k miles, with major services done at 30k, 60k, and 90k miles. Minor services can range from $500 for an oil change, pollen filter change, air filter change, and inspection of the vehicle. A major service will include the aforementioned, along with spark plugs, and a much more thorough inspection of every aspect of the car. A major service can easily run over $1200.
Engine: Intermediate shaft failure. I like to call this catastrophic engine failure, because it typically will require a new engine. Some of the C2/4's have had serious failure due to the intermediate shaft failure. Is it all that common? Not really, but it still does occur on occasion. This is where a warranty will save you, as it will typically run well over $10k for a rebuilt engine to be put in the car. Porsche dealers do not even try and fix the engine, they are boxed up and sent back to Germany where they are inspected. Porsche will install a remanufactured engine which should not suffer the same fate. Having talked to some dealer techs recently (as an independent, I have only seen 1 or 2 failures in the last 5 years), the techs have told me that Porsche has replaced a lot of engines that could have been easily repaired at the dealer. There is a fix to the intermediate shaft issue if it is caught early enough. If you hear the engine making an odd ticking at start up (something you don't normally hear), and you shut it down, chances are the IMS can be repaired. Porsche wanted to be known as having great customer service, so they decided replacing the engine was far better for that. Unfortunately for a dealer tech, you get paid more to repair items, than to replace items under a warranty/good faith type claim. UPDATE: LN engineering has come out with a bearing replacement/upgrade kit for these motors. Recent evidence is suggesting that the failure is happening to LOW mileage cars that are not driven enough. Condensation builds up in the oil, seeps past the IMS bearing seal, and erodes the bearing internally. The higher mileage cars are not seeming to be affected by this at all. I recently pulled a bearing out of a 100k mile 996, and it was like new. LN has a ceramic bearing which does not use an outer seal which allows oil to flow freely through the bearing to keep it lubricated and prevent erosion.
Wheel Bearings: I have replaced quite a few wheel bearings now in the 996/boxsters. The sealed bearing will start to growl, like excessive road noise or cupped tires when they go. Since they are a 2 piece sealed system, they will not exhibit typical bearing play in the wheel. Not a huge deal, but it does happen.
