Porsche Repair: Porsche 944S2 odd oil pressure related noise!, porsche 944s2, balance shaft

Question
Hi, I have a 1990 944 S2. It is in concours condition and only has 89K on the clock. Recent mechanical check result was that it was 90% mechanically perfect. BUT, when the car is running and up to temperature, there is a curious hum/whine when the oil pressure is at @4.5 bar. Under normal running, the oil pressure is up at 5bar steady and will drop at idle to a steady 3 bar when hot. Along with the noise, you can feel it slightly through the clutch pedal and the steering. It occurs if in neutral or in gear, but only at the above oil pressure. Someone suggested it was the power steering pump, but can this be as it is clearly related to the oil pressure? Any suggestions? Steering is ok, tad heavy, especially after one full turn. There are no adverse running when the noise is there, just damn annoying.

Answer
Paul;

It is hard do diagnose noises over the internet, but I'm thinking that you may have your Timing Belt or Balance shaft belt not adjusted properly.

When was the last time the TB & Balance shaft belt, rollers & tension changed.

Use a stethoscope and probe around to locate the area that is making the noise. Take the probe section off of the steathoscope and use it like a small parabolic microphone.