Alfa 159 Turbo Noise
I have recently received delivery of my Alfa 159 LE (1.9 JTDm) and although I am very pleased with the car there appears to be a niggling fault which the Alfa dealer does not seem to be able to get to the bottom of as follows:
I have noticed what seems to be an excessive hissing noise from the turbo when accelerating very gently. This noise goes away when accelerating hard. I say that it seems to be excessive because generally the car is quiet with no rattles and the diesel engine is reasonably quiet but this noise makes the car quite noisy in slow traffic where you are accelerating and decelerating regularly.
Additionally after accelerating very gently in 3rd gear at around 30 mph or 4th gear at around 40 mph then if you take your foot off the accelerator (tends to happen more when going up hill) you get a kind of a short grinding or vibrating noise as the transmission begins to drive the engine instead of the engine driving the transmission.
I have taken the car into the dealership and they checked out all of the turbo and intercooler hoses and replaced one of the hose clips which they thought may or may not be contributing to the noise. In addition to this they mentioned that there was a “Service News” letter prepared by Alfa Romeo (which I currently have a copy of) which stated that “if customers experienced air bubbling/blowing type noises” then various checks should be made to the turbo and intercooler hoses. Also “if the checks gave a negative outcome (all ok) then no replacement operation needed to be carried out and the customer should be told that the noise is not a fault but a feature produced by the air circulating in the inlet system pipes and does not, under any circumstances, adversely affect the operation of the vehicle” (which is what was told to me).
I would like to determine if this is normal behaviour for the 1.9 JTDm engine (as prior to purchasing the car I test drove a 159 Lusso with the same engine spec and did not notice this feature at all). If it is normal then I will just have to put up with it but it is a bit disappointing after spending so much money and discovering that this is a normal characteristic instead of a fault and that no fix appears to be available.
Any comments would be greatly appreciated for either of the problems mentioned above.