Strange Turbine Noise on Cold Start – Video Included

[Stef914]

Hi everyone,

For the past few months my 2001 Boxster 2.7 has been making a strange noise on cold start only, and I’m trying to get some peace of mind about it.

The sound appears about 5 seconds after startup, only when the car has been sitting for about a week or more and the engine is fully cold. It lasts roughly 1–2 minutes, then disappears completely and the engine sounds normal.

The noise is high-pitched and almost metallic, the closest comparison I can think of is something like a small turbine or metal shaving / rotating metal sound. It seems to come from the passenger side of the engine bay.

For context, the car recently had an oil change, water pump, and thermostat replaced, but the noise was already present before that work.

I’m told this might be the secondary air pump, which would make sense since it only happens during cold start, but I wanted to ask here and get some feedback from other owners.

I made a short video so you can hear it — the sound starts around the 5-second mark:

https://youtube.com/shorts/4rou4bkALb4

Does this sound like a secondary air pump starting to age, or something else I should look into?

Thanks in advance for any thoughts.