VW Bora TDI Power Loss: Common Turbo Failure Signs

I had a very similar issue with my 2006 VW Jetta TDI. As someone with moderate experience working on diesel engines, let me share what happened. The symptoms matched yours exactly, increased fuel consumption, power loss, and constant check engine light. Initially, the workshop suspected worn piston rings, but after thorough diagnostics, they discovered the root cause was actually a damaged turbocharger caused by a clogged fuel injector. The interesting part was that I had just had work done on the fuel system, and the damaged turbocharger was actually a result of that previous repair not being done correctly. Since it was a consequential damage, the workshop covered the entire repair cost under warranty. The repair involved: Replacing the turbocharger, Installing new fuel injectors, Cleaning the entire fuel system, Recalibrating the engine management system To help diagnose your case more precisely, could you share: Current mileage on your Bora, When was the last fuel system service done, Any recent repairs or maintenance, Whether you notice any unusual exhaust smoke, If there are any specific error codes showing Also, have you noticed any whistling sounds or excessive exhaust smoke? These could be key indicators of where the problem lies.

After getting my fuel injectors replaced and turbocharger inspected, the performance issues persist. The check engine light remains on despite these repairs. My mileage is now at 75184km and the timing belt was replaced during the last service. Most concerning is the black smoke from the exhaust which started appearing after the recent work. Could this indicate the initial diagnosis was incorrect? Looking for advice on next diagnostic steps to properly resolve this ongoing issue.

Thanks for the update on your Bora. Having gone through nearly identical issues with my VW, I can tell you that black smoke after fuel injector replacement is often a red flag. The persistent symptoms despite the repairs point strongly toward a head gasket issue that was missed in the initial diagnosis. When I faced this with my car, the black smoke appeared because the head gasket failure allowed coolant to enter the combustion chamber, a problem that became obvious only after the fuel injector replacement cleared up the initial symptoms. The repair sequence on my car ended up being: Head gasket replacement, Cylinder head inspection and resurfacing, New head bolts installation, Timing belt realignment check The timing belt replacement during your last service is actually relevant here, sometimes if the tensioning isnt perfect, it can contribute to head gasket stress. In my case, the head gasket failure was partially due to this. Before proceeding with more repairs, request a compression test and cooling system pressure test. These will definitively confirm if youre dealing with a head gasket problem rather than throwing more parts at the symptoms.

Thanks for your insights about the head gasket potentially being the root cause. Since you worked on a similar car, your experience is particularly valuable. My mechanic just ran the compression and cooling system pressure tests as suggested. Results show significant pressure loss in cylinder 2, pointing strongly to the head gasket theory. The intake manifold also shows signs of coolant residue, which apparently is another classic symptom. The workshop has quoted 1200€ for a complete head gasket replacement job, including resurfacing the cylinder head and replacing all associated gaskets and bolts. They also recommend inspecting the crankshaft seals while the engine is partially dismantled. Given the evidence and my cars symptoms matching your experience almost exactly, I think Ill proceed with the repair. Really hoping this finally resolves the performance issues and black smoke problem that has been plaguing my Bora. Will update once the work is completed.