Alfa Romeo Repair: Alfa 156 TS crank noise, hydraulic valve lifters, crankshaft bearings

Question
hi Mr. Sokol
My 2L (model 2000) Alfa had that diesel-like noise, so I replaced the variator, water pump, timing belts and tensioners, together with pistons oil-retainers (is that the name in English?).
As work is finished, there is still one unpleasant noise (that might me refered to as a ticking valve, but is coming from the lower engine side. It occurs when:
1. fast rpm acceleration
2. certain rpms (like there is a kind of resonance.... if you know what I mean) around 2400 and 4500 rpm.

One last symptom: on idle rpms, the oil lump is blinking (just as one would expect if the engine idle rpms are set too low).
Can you think of anything? My mechanic (the one that repaired the variator says it might be something with crankshaft bearings or so).
Thanks alot!

Answer
This is the symptom of worn rod bearings.  I have found that once more the industry is going through a learning process, this time by recommending too low an oil viscosity to help with fuel mileage. I have two vehicles that the manufacturers recommend using 5w-3o or 10w-30 oil and I have had to switch to 5w-50 because I do not want to use 20w-50 because of varying ambient temperatures.

(I think you meant hydraulic valve lifters).