Strange new noise from engine - 1998 911

[slaskowski]

After a rather spirited drive this morning here in South Florida, I heard a strange noise coming from my engine.  As my 911 is a Cabriolet, I first thought it was another car around me.    When I got back to the garage I confirmed it was indeed me :(

In summary:

• The sound goes on for 30 seconds then would stop.  It would take another 2-3 minutes then it would come back on.
• Something that caught me by surprise was that I turned the car off and was going to turn it back on to see if it continued.  When I just turned the key to turn-off the engine immobilizer the sound came on even though I had not physically cranked the engine yet.
  • When I started the engine it did not come back on.   I let it run for another 5 minutes but the noise did not return
• I checked to see if it was throwing any ODB2 codes with my Durametric, however, all was clear.
• Oil levels are fine
•  
• I have enclosed two videos
  • One is with the engine running (and the sound disappearing)
  • The second is when I turned the key, but not yet cranked the engine.

 

Any advice/insight into what it could be would be appreciated.    Also would like to know can I drive it to my mechanic (assuming that I would need to), would I be causing any long term problems?

 

Thanks - Steve

[IXLR8]

This was a long time ago. Any update as to what it was.

 

I would have used a stethoscope and listened to various parts of the engine, both on top and below. I know noises can travel in an engine making it difficult to pin point it, but it might help.

Edited March 25, 2020 by IXLR8