Giulietta Diesel's Power Loss & Smoke Points to PCV Issue

I had almost identical issues with my Alfa Romeo 159 diesel from 2015. Having some experience with diesel engines, I recognized similar symptoms of white smoke during acceleration and idle problems. The crankcase ventilation system was indeed defective, causing excessive emissions and that characteristic smoke from oil vapor not being properly recycled. After the check engine light came on, I took it to a workshop where they confirmed the PCV valve had failed, allowing pressure to build up in the crankcase. The repair took about 4 hours and cost 360 Euro, including parts and labor. The mechanics also cleaned the intake manifold since oil residue had built up there due to the leak. Since the fix, the engine runs much smoother with no more smoke issues. Before jumping to conclusions though, could you share: Current mileage on your Giulietta, Type of smoke color (white, blue, or black), Does the smoke appear at idle or only during acceleration, Any unusual sounds from the engine, Recent maintenance history This information would help confirm if your symptoms match what I experienced with my 159.

Thanks for sharing that experience. My Giulietta has 94581 KM and had its last major service about 6 months ago. The smoke is definitely white and appears mainly during acceleration, though occasionally at idle too. There is a slight whistling noise when accelerating hard. The symptoms match exactly what you described with your PCV valve malfunction. I will have the ventilation system checked by a workshop, focusing on the crankcase pressure. Regular maintenance clearly wasnt enough to prevent this issue. Did you implement any specific preventive measures after your repair to avoid future valve problems?

Thanks for those additional details. After my PCV valve repair on the 159, I implemented a more rigorous maintenance schedule specifically focused on the ventilation system. The whistling noise you mention during acceleration was also present in my case, it was caused by pressure escaping through the failing valve. Your mileage is very close to when my malfunction occurred (around 92000 KM). Since the repair, I have done these preventive steps: Oil changes every 10000 KM instead of the standard interval, Regular checks of the breather hoses for oil residue, Cleaning the air intake system every 30000 KM The workshop also suggested using high-quality oil that meets manufacturer specs, as lower grade oils can leave more deposits in the ventilation system. This comprehensive approach has prevented any recurrence of smoke or valve issues for the past 40000 KM. The cost comparison might be useful, my total repair was 360 Euro, but preventive maintenance runs about 80 Euro annually. Much cheaper than dealing with another complete system failure.

Thanks for all this information. Based on all the matching symptoms and your success with the repair, I will schedule a workshop visit this week. The whistling noise and white smoke during acceleration seem to point clearly to a PCV valve issue, just as you experienced. My 94581 KM is right in that problem zone you mentioned. I appreciate the maintenance tips, especially about the oil changes and ventilation system checks. Will definitely implement your suggested preventive measures after the repair to avoid future problems. The 360 Euro repair cost seems reasonable compared to potential engine damage from a neglected ventilation system. One quick follow-up, did you notice any improvement in fuel consumption after the PCV valve replacement? With my current reduced power issues, I suspect I might see better efficiency once this is fixed.