Hi folks,
This request for advice refers to a 1998 Vectra 2.0 Litre DTH Diesel Turbo Ecotec engine with 110K+ on the clock.
After running just fine for the last 15K since I bought this vehicle, the engine now produces (over the last 100 miles or so) a very noticeable high pitched whistle (variable frequency - turbine like) when pushed hard at RPMs above 2,500. The noise vanishes if I reduce throttle pressure even without reducing road speed. No such noise arises if I get to the same speeds gently with slower acceleration.
Any experiences would help to diagnose this. It's my first turbo diesel and I have been very happy with the engine after spending some time rectifying oddities when I first got it - like EGR valve and airflow monitor unit. I have grown to love the characteristics of a modern turbo diesel and this vehicle suits my needs perfectly.
The Engine management light does NOT come on under these circumstances and I am guessing at either exhaust leaks around the waste gate or manifold or, perhaps, something VERY expensive with the turbo.
My only clue is that the sound drops away fast with throttle - not speed - reduction, whereas I would have thought anything chronic with the turbo would continue with the turbo still spinning fast.
Could I temporarily disconnect the vacuum pipe to the waste gate actuator (and block it with something) to road test it or is it immediately likely to damage something like that?
Direct experiences with this engine would be most welcome. It is pretty difficult to get good access to the manifold with the turbo in place to investigate it while running and, anyway, it does not happen under light loading. Thus, revving the engine with a stethoscope at the manifold is unlikely to help.
As always, TIA,
Tony.