Civic Diesel Problems: Boost & Black Smoke Mystery

Hey there! I had a similar issue with my 2010 Honda Accord diesel last year. I have some experience working on cars, but turbo-related stuff is definitely workshop territory for me. Had almost identical symptoms, black smoke, power loss, and that annoying whistling noise. Turned out to be a faulty wastegate valve. Had my trusted mechanic diagnose it properly, and they replaced the whole assembly. Set me back about 860 Euro, but it fixed all the issues completely. From your description, it really sounds like the same problem I had. Though before jumping to conclusions, Any specific error codes from the check engine light? When do you notice the whistling sound most (idle, acceleration)? Has your fuel consumption increased lately? By the way, if it helps, I know the Civic and Accord share similar turbo components for that generation. Let me know these details and I might be able to offer more specific advice!

Thanks for the detailed response! Yeah, I've got 239700 KM on the clock and last service was just 2 months ago. The whistling is most noticeable during acceleration, especially between 2000-3000 RPM. Fuel consumption has definitely gotten worse, I'm using about 20% more diesel than usual. Haven't checked the error codes yet, but planning to get that done tomorrow. Really hoping it's just the wastegate like in your case. Though 860 Euro sounds painful, it's better than having to replace the entire turbo. Did you notice any early warning signs before it got really bad? Just wondering if I should've caught this earlier.

Hey again! Yeah, looking back at my Accord's situation, I did notice some early warning signs about a month before it got really bad. Started with a very subtle drop in power that I initially brushed off as just regular wear and tear. The whistling noise was super faint at first, you could barely hear it unless you were really paying attention. About your car's symptoms, it's like déjà vu! Those RPM ranges you mentioned are exactly where my issues were worst too. And that 20% increase in fuel consumption? Spot on with what I experienced. Before I got mine fixed, I actually tried limping it along for a couple weeks (bad idea, I know ). The symptoms just got progressively worse until one morning it barely wanted to start. That's when I finally bit the bullet and took it to the shop. One thing I learned, if you're getting it fixed, make sure they check the turbo oil feed pipe while they're at it. When they opened up my engine, they found it was partially clogged, which probably contributed to the wastegate failure in the first place. Might save you from future headaches! Keep us posted about those error codes when you get them. Really curious to see if they match up with what I had!

Thanks so much for sharing your experience! That's super helpful, especially about the oil feed pipe, definitely going to mention that to my mechanic. It's weirdly comforting knowing someone else went through the exact same thing. You're probably right about not waiting too long. I've already been putting this off for a couple of weeks, and after hearing how yours got worse, I'm going to get it looked at first thing tomorrow. Really don't want to risk being stranded somewhere or causing more damage. I'll scan those error codes tomorrow and update this thread. Fingers crossed it's just the wastegate! Even though 860 Euro is a lot, it beats having to shell out for a complete turbo replacement. You're a lifesaver, thanks for all the detailed info!