Alfa 156 whinning noise fixed!
After the car was taken for its 108,000 mile service where I had both the fixed & variable aux belt tensioners (and aux belt replaced) the whinning noise has totally disappeared and now I can enjoy once again the growl from the exhaust note as accelerating from low speed which I had forgotten how fantastic it sounds (now I can hear it!!).
Thank you for everyone who has offered suggestions.
Unfortuntely the engine is not running right, before the service the engine was smooth with no hesitations and drove powerfully right up to max speed. Since the service which included replacing the cam & balancer belts and tensioners, the engine has idled roughly especially from cold (not quite a misfire but similiar) and I suspected that the cam timing was not right.
I took the car back to the garage where they confirmed that the timing was out on the exhaust cam, and kept the car for a day to put right! Unfortuntely when i picked up the car, the vehicle was better but not like it was before the service! it was still a little rough at idle and when driving would hesitate just around 40 mph whether you drive smoothly up to this speed or accelerate hard it would seem to hold back until the speed reached approx 60 mph and then would be smooth all the way to max speed!
After talking to the mechanic who had done the work on the car, I realised that they did not have the 2.0 JTS cam looking tools (which are different from the 2.0 twin spark) and realised that without the locking tools, it is almost impossible to accuratly reset the cam timing!
I then decided to take the car to a new garage that for a few years, I have looked at on the web called the the Alfa Workshop based in Royston in hertfordshire. The website has always looked professional providing lots of advise to Alfa enthusiast (like me). I booked the car into the workshop and with them using the official cam locking tools found that the exhaust cam was still out by a couple of teeth.
I though great this has fixed the car, but when they drove the car the mechanic working on the car was not happy with the performance, and when I drove it with him next to me using the Alfa diag tool, no fault could be found but although the vehicle drove better it still had the hesitation issue.
After a complete morning of swapping every sensor that could be easily swapped, the engine was still the same! It was decided to drive the vehicle around for a couple of weeks to see if the engine management system adaptive memory would correct this issue automatically as it relearned the engine with correct cam timing but it is still the same.
I have also noticed that when cold, it can sometimes run more roughly then when hot and once the engine management system warning system beeped and flashed it warning message when just idling at cold (I suspect cam sensor correlation fault) still cam timing.
This beeping and warning message continued for a couple of minutes until I just blipped the throttle as the engine warmed up and the beeping and message disappeared.
My question is that I do not believe the cam timing is out, as I saw the cam locking tool being used to check and reset the exhaust cam timing, but I woondered if the cam timing solenoid that operated on the cam timing can become faulty (not electrical) but mechanical either sticking or leaking oil pressure to operate the exhaust cam incorrectly, as the fault changes with temperature and during driving at times the fault almost disappears and then comes back!
In addition before the whinning noise, when the engine was cold I got the common tapping noise from I suspected the cam timing solenoid which is very very common, but could not hear this with the whinning, but I have now noticed that this tapping has disappeared with the engine idling frrom cold, which makes me wonder if the cam timing solenoid is causing the problem?
Any ideas or anyone with similiar experiances who can advise would be most appreciated.