Hello fellow Briskodians!
I'm now the proud owner of a Mk1 Fabia and aside from the fact that everything works as expected, it makes a droning noise at certain speeds that sounds like trouble!
All speeds mentioned will be as indicated by the speedo, my observations are repeatable and accurate so far.
Between 0-25mph everything is nice and quiet, some vibration in the steering wheel that feels like an unbalanced wheel.
At around 25-30mph the droning noise starts to fill the cabin, vibration in the steering wheel as at lower speeds.
At 40mph the noise reaches its first peak, vibration in the steering wheel slightly more intense.
At 45mph the noise reaches its first "trough", noticeably less than at 40mph, vibration in the steering wheel as before.
At 50mph the noise reaches its second peak, vibration in the steering wheel is less than at 40mph.
At 55mph the noise reaches its second "trough", louder than at 45mph.
At 60 mph the noise reaches the absolute maximum intensity I've experienced so far, a loud resonating boom fills the entire cabin. Vibration in the steering wheel is less than 50mph.
Accelerating to 65mph the noise exponentially decreases and only leaves a slight hum with no vibration in the steering wheel. This is the sweet spot and is a perfectly acceptable level of cabin noise on the motorway. The hum progressively increases in loudness up to 85mph just as you would normally expect in any car (I wouldn't dare go any faster in this Fabia ).
The variation in noise between speeds is the same both in acceleration and deceleration, the same volume always occurs at the same speeds, very repeatable and very predictable.
Additional observations:
Engine and gearbox do NOT affect the noise in any way. There is no difference between gears or neutral, the noise remains entirely unaffected at any of the above mentioned speeds.
Any input is much appreciated, I understand that this may seem like a wheel bearing but the symptoms do not agree, wheel bearing noise only gets worse with speed, not better.
Are these symptoms typical of wheel imbalance, wheel alignment or both? Also are there any telltale signs I can readily observe on the tyres that would help diagnose this?