Audi A7 Diesel Glow Plug Issue Causing Cold Start Problems

As someone with moderate DIY car repair experience, I had a very similar issue with my 2015 Audi A6 diesel engine. The engine light came on during cold starts, and the preheating light stayed illuminated, causing rough idle issues. After some initial troubleshooting, my workshop diagnosed a faulty glow plug in cylinder 2. The total repair cost was 440 Euro, which included diagnostics, parts, and labor. The symptoms disappeared completely after the repair, and cold starts have been smooth since then. The tricky part with diesel engine glow plug issues is that they can sometimes mask other problems. Would you mind sharing: * Have you noticed any black smoke during startup? * Does the engine misfire only during cold starts or also when warm? * Have you scanned for error codes? * How many kilometers/miles are on your engine? This information would help determine if your A7 is experiencing the same issue my A6 had, or if there might be something else going on. Based on my experience, I would recommend having it checked soon, as continuing to drive with faulty glow plugs can lead to starting problems and potentially cause additional engine stress, especially during cold weather.

Thanks for the detailed feedback. My A7 has 59131 KM and had its last service 4 months ago. After reading your response, I checked and noticed black smoke during cold starts. The engine seems to run fine once warmed up, but the initial startup is quite rough. The check engine light pattern matches exactly what you described. I havent done a diagnostic scan yet, but based on the similar symptoms, it does sound like my diesel car might have the same glow plug issue. The cold start problems have definitely gotten worse over the past few weeks. Would you recommend getting all glow plugs replaced at once, or just the faulty one if identified through diagnostics?

Based on what you described, the symptoms are nearly identical to what I experienced. Since you mentioned the black smoke during cold start and rough idle that improves after warmup, it strongly points to glow plug issues in your diesel car. In my case, after the initial repair of just one glow plug, I ended up having another one fail within 6 months. The second repair cost me about 380 Euro. Looking back, I should have replaced all glow plugs during the first repair. The logic behind replacing all glow plugs at once: * If one fails, others are likely to follow soon * Labor cost is nearly the same * Prevents multiple workshop visits * Ensures consistent cold start performance The engine light and cold start issues you describe are textbook glow plug symptoms. However, getting a proper diagnostic scan would still be wise to rule out other potential problems that could cause similar engine misfire patterns. The total cost for replacing all glow plugs typically runs between 600-800 Euro, depending on labor rates. While this might seem steep compared to single plug replacement, it usually proves more cost-effective in the long run.

Based on your feedback and experience, I've decided to go ahead and schedule a workshop visit next week. The matching symptoms, especially the black smoke and rough idle during cold starts, have convinced me this needs attention soon. You make a really good point about replacing all glow plugs at once. Given the age of my car and the fact that these components tend to wear at similar rates, spending 600-800 Euro now makes more sense than facing multiple repair bills and workshop visits. I'll make sure to get a diagnostic scan first to confirm the engine misfire pattern and rule out other issues. The declining fuel efficiency and increasingly difficult cold starts are clear signs I shouldn't wait any longer. Thanks for helping me understand what to expect, this will definitely make my workshop visit more productive.