A1 TDI Rough Idle Points to Failing Engine Mount

As someone with some car repair experience, I dealt with similar vibration issues on my 2008 A3 TDI. Initially thought it was a defective engine mount causing the rough idle, but after inspection, it turned out to be a faulty wiring connection to the engine management system. The symptoms were nearly identical, strong vibrations during idle and engine-related codes. The rubber mount looked suspicious at first, but the real culprit was much simpler. A corroded cable connection was causing irregular signals, leading to the engine running rough. The repair was straightforward, the workshop cleaned and repaired the connection points, which resolved both the vibration issues and error codes. Total cost was 95 Euro for diagnostics and repair work. Before jumping to conclusions about mount failure, could you share: Which specific error codes are you getting? Does the vibration change with engine temperature? Have you noticed any other electrical issues? This information would help determine if your issue matches what I experienced or if you truly have a defective engine mount. The symptoms can be quite similar, but proper diagnosis is crucial for avoiding unnecessary repairs.

Last serviced at 159246 KM and the issue persists. Since posting, I noticed fluid leaking around the mount area and the vibrations have gotten worse, especially when shifting gears. The Check Engine Light has come on twice this week. Took it to a shop and they confirmed signs of mount wear on both the engine and transmission mounts. Getting quotes now but wanted to verify if this is a common mounting bracket issue with these models before proceeding with repairs. The error codes are specifically pointing to engine misalignment, which makes sense given the visible mount failure. Would appreciate input on whether I should replace all mounts simultaneously or if changing just the damaged ones is sufficient. Currently weighing repair options between 350-500 Euro based on initial quotes.

Thanks for the update. Having dealt with similar mount issues on my A3, I definitely recognize those symptoms. After my wiring fix, I actually ended up replacing all engine mounts about 6 months later when I noticed fluid leakage like yours. The mounting bracket system on these models is known to show wear around 150000-180000 KM, so your timing fits the pattern. When my failed mount started leaking, the rubber mount deterioration quickly affected the others due to increased stress on the entire mounting system. Based on my experience, I strongly recommend replacing all mounts together. When I only changed the obviously failed mount, the increased strain on the old ones led to another mount failure within 2 months. Ended up spending more doing them separately than if I had done all at once. The vibration issues will only get worse, especially during gear shifts, as the engine movement becomes less controlled. The complete mount replacement resolved all my alignment-related codes and restored proper engine stability. Your quote range of 350-500 Euro sounds reasonable for a full mount replacement. I paid 420 Euro for all mounts including labor, and it was worth every cent for the improved driving experience and prevention of future mount failures.

Thanks for all the input. After reading through the responses and checking my car again today, I have decided to go ahead with replacing all mounts at once. The vibration issues have definitely gotten worse since my initial post, and the mount failure symptoms are now unmistakable. The shop I contacted confirmed significant rubber mount deterioration across multiple mounting points. Given the mileage and the visible fluid leaks, it makes sense to address all potential mount wear issues in one repair session. They quoted me 475 Euro for a complete mount replacement including labor, which seems fair based on the feedback here. Going to schedule the work for next week before the current mount failure leads to additional problems. Will update once the repair is done, but based on the symptoms and professional assessment, this seems to be the right call rather than just fixing the obviously failed mount.