So, I thought my Cayman "strange drivetrain noises" drama was over (see this thread: http://www.planet-9.com/987-cayman-...ngine-noise-my-cayman-s-not-blown-engine.html ) : a few weeks ago, I noticed an intermittent "tapping" or "flapping" sound at idle in my garage right after an oil change. After a day or so, this intermittent noise seemed to turn into a more regular "tapping" noise. Apparently, the more regular, rhythmic noise was a different issue entirely.
Because of all the internet stories about the m96 and m97 engines, I feared the worst. I sent an oil sample to Blackstone and had it towed to my local speciality shop, where they scoped the engine, checked the oil filter and sump for debris, and found nothing wrong. Moreover, the oil analysis came back from Blackstone as being perfectly within specifications; in other words, my car had a clean bill of health. During the scoping of the cylinders, the mechanic noticed that a spark plug was loose; sure enough, tightening down the spark plug caused the rhythmic tapping to go away -- it was just compression escaping from the spark plug hole all along.
Well, it turns out that that didn't solve the initial noise that I heard awhile back. This noise is hard to describe, but I would call it a very intermittent and irregular tapping noise that is totally independent of engine rpms; you'll hear a tap, and then a few seconds would go by and you'll hear two taps in a row. And then there will be a long, quiet stretch, and then another couple taps, etc. When you rev the engine, you no longer hear the tapping; if the car is still making the noise, it is separate from the noise of the engine and can't be heard over the sound of the revving engine.
Moreover, I only hear the noise when the car is WARM but not HOT -- you can start to hear it 30-45 sec after starting the car when it's cold, but if I go out for a long drive, it doesn't make the sound when I pull the car into the garage and let it idle there.
It doesn't sound good, but I'm comforted by the fact that it seems to have nothing to do with the rotation of the engine internals. Part of me wonders if it has something to do with a pulley -- or maybe the water pump?
I also notice that if I push in the clutch, the noise lessens but doesn't go away completely. Then, if I put the car in gear and let it roll in 1st or Reverse, the noise stops completely. Let out the clutch, it comes back. Push the clutch down again and it's gone. So maybe it's a throw-out bearing? Or gear chatter? Or something to do with the clutch disk or flywheel?
Anyhow, if you guys could take a listen and let me know what you think, I would be appreciative. You'll have to listen carefully to the video: you first hear the tap right before 7 seconds, but then it gets more regular, with a couple quick taps at 8-9 seconds. There quiet stretches in between when you won't hear anything other than an otherwise fine-sounding flat six. Near the end of the video, I move the camera closer to where the gearbox meets the engine, and you can hear the tapping much more clearly then.
Thanks, and I eagerly await your thoughts.
Because of all the internet stories about the m96 and m97 engines, I feared the worst. I sent an oil sample to Blackstone and had it towed to my local speciality shop, where they scoped the engine, checked the oil filter and sump for debris, and found nothing wrong. Moreover, the oil analysis came back from Blackstone as being perfectly within specifications; in other words, my car had a clean bill of health. During the scoping of the cylinders, the mechanic noticed that a spark plug was loose; sure enough, tightening down the spark plug caused the rhythmic tapping to go away -- it was just compression escaping from the spark plug hole all along.
Well, it turns out that that didn't solve the initial noise that I heard awhile back. This noise is hard to describe, but I would call it a very intermittent and irregular tapping noise that is totally independent of engine rpms; you'll hear a tap, and then a few seconds would go by and you'll hear two taps in a row. And then there will be a long, quiet stretch, and then another couple taps, etc. When you rev the engine, you no longer hear the tapping; if the car is still making the noise, it is separate from the noise of the engine and can't be heard over the sound of the revving engine.
Moreover, I only hear the noise when the car is WARM but not HOT -- you can start to hear it 30-45 sec after starting the car when it's cold, but if I go out for a long drive, it doesn't make the sound when I pull the car into the garage and let it idle there.
It doesn't sound good, but I'm comforted by the fact that it seems to have nothing to do with the rotation of the engine internals. Part of me wonders if it has something to do with a pulley -- or maybe the water pump?
I also notice that if I push in the clutch, the noise lessens but doesn't go away completely. Then, if I put the car in gear and let it roll in 1st or Reverse, the noise stops completely. Let out the clutch, it comes back. Push the clutch down again and it's gone. So maybe it's a throw-out bearing? Or gear chatter? Or something to do with the clutch disk or flywheel?
Anyhow, if you guys could take a listen and let me know what you think, I would be appreciative. You'll have to listen carefully to the video: you first hear the tap right before 7 seconds, but then it gets more regular, with a couple quick taps at 8-9 seconds. There quiet stretches in between when you won't hear anything other than an otherwise fine-sounding flat six. Near the end of the video, I move the camera closer to where the gearbox meets the engine, and you can hear the tapping much more clearly then.
Thanks, and I eagerly await your thoughts.
