Iv'e read a lot on this, but can't make up my mind on what to do.
I just bought an 2006 Alfa 147, 1.6TS 105HP With 91000km on the clock (about 60000 miles)
The engine has a slight knocking noise. I hear it on idle, it seems to follow the revs, but gets more apparent as the revs fall.
I'm not able to say if this is top or bottom end problems. The sound is a bit higher when I lay under the car, so I suspect crank bearings.
BUT: In my experience, with bad crank bearing/rod Knock it gets bad fast. This have been the same for about 2000km with mostly high speed highway driving (3500-4000 rpm) and some city-driving. It does not get any louder or worse. The other thing is that on idle the noise disappears from time to time, its there for some seconds, disappears for some seckonds and get back. I would believe that rod-knock would be more consistent?
The other thing I suspect is a bad aligned timing-belt. Previous owner had it replaced, the old one was in he trunk when I bought it. But I got a feeling this was a garage job, witch is never good... Could this cause the knocking?
Could also be lifters. Tried the 15-15 second interval rev-thing I found here, and it got a bit better, but came back after a day or two.
What do you guys think?
Thanks for any help and suggestions!
Last edited by mach1frh; 16-08-16 at 10:02.