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Originally Posted by Brucelee
Several years ago, I sold a 2000 Boxster to my neighbor. She loved it so much, she went out and bought a new 04 last year.
On Tuesday, the half shaft let go and, well, in short, goodbye to the engine.
Talk about upset, she is!
The good news is that the new engine should be in by Friday or Monday, no charge.
The bad news is the car is now "suspect" in her eyes. She wants to know why an engine with 10K miles on it should fail while sitting at a stop sign.
I did not have a good answer for her.
Is Stuttgard listening?
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Bruce,
By half-shaft I think you're talking about the Intermediate Shaft. In '03 I believe, Porsche re-engineered this piece and went from a Double- Bearing at the end to a Single-Bearing one, supposedly to reduce vibration.
The intermediate shaft drives the oil pump. When the Intermediate Shaft breaks, a small stud which protrudes from the Intermediate Shaft Flange Seal breaks off and rattles around in the Bell Housing - Not Good!
From the flywheel side of the engine a 13mm nut is centered in the Intermediate Shaft Flange Seal. That nut and the stud its attached to is what breaks. This causes Oil to pour out of the hole left in the middle of the Flange Seal.
At this point in the Failure, the Crank is still driving the intermediate shaft so Oil Pressure is maintained. But, once the engine is stopped, Oil just flows from it similar to catastrophic RMS Failure.
The Intermediate Shaft also drives the Camshafts. The Intermediate Shaft has two Sprockets at one end and one at the other . The end with two Sprockets has one Sprocket for the Drive Chain from the Crank, the other drives the Cams. So, in addition to piercing the Oil Flange Seal when the Shaft breaks, causing the Oil to drain from the Engine, it can also interupt the Valve Timing. The M96 Engine is an
Interference Engine and so when breakage occurs, you can also bend Valves and Crack Pistons - also NOT Good.
Unlike RMS Failure, which tends to occur on Cars under 20k mi., the Intermediate Shaft can fail even at higher mileage, but is less common than RMS issues. Although not restricted to post '02 models, it does seem more prevalent in them. While less common than RMS Failure, Intermediate Shaft Failure almost always destroys the Engine when it goes. There is no maintenance or Driving Practice known to reduce the likelyhood of such a failure. Hope this helps...
Happy Motoring!... Jim'99