Whirring sound when engine is cold
 

The 944 has developed a fairly loud "whirring" sound that remains until the car is completely up to temperature.

My completely unknowledgeable instinct says belt noise, maybe a tension problem? I'm pretty sure that all of the belts have been replaced. Any ideas?

I am sure the current 944 Guru will jump in here, you know, the one who loves working on 944s. Any way, from your brief description, I would guess at Torque tube rumble. I don't think you would hear improperly tensioned belts (could be serious problem).Could also be clutch related.
Dirk

If the noise is coming from the front of the engine I would first suspect the timing/balance shaft belt tensioners or rollers unless they are relatively new. It could also be a water pump, alternator, or power steering pump that is getting tired.

I have yet to meet this guy and would wonder about his and the guy in the red suit’s existence. All are good things to check but if noise corresponds with winter solstice the recent cold weather may have made some old fan belts sing. And if you don’t know when your timing belts and water pump were last changed you are rolling the dice and “craps’ are going to be expensive.