My Peugeot 208 Timing Chain Noise Returned After the Service “Fixed” It With Thicker Oil

We took our 2021 Peugeot 208 1.5 BlueHDi with 70,000 km to Balıkesir Peugeot Beyaz Service by tow truck because the engine noise indicated the car should not be driven cold and needed to rest. The service told us they would change the oil and filter and then “let AI listen” to the engine, but instead of using the correct 0W-30 oil, they used thicker 5W-30 oil to temporarily reduce the noise and have the AI “evaluate” it in that condition. We explained that this is illogical and that thicker oil can temporarily mask this type of noise in many vehicles, but they continued with scripted statements that appeared designed to avoid approving a real repair or replacement. They insisted the vehicle could not be evaluated without this procedure and said it was mandatory. As expected, the noise did not show up during their test, so they claimed no replacement was needed and sent us away with thicker oil in the engine. After the thicker oil, the noise decreased for about five days, but then it returned exactly as before, which was predictable. In other words, the brand is trying to “cover up” the issue, dismissing the customer and sending the vehicle away without addressing the root cause. They do not seem to care whether the timing chain could fail while driving and cause an accident, or whether delaying proper repair will create more serious damage and higher costs and harm the customer financially and psychologically. As a result, we cannot safely use the vehicle right now because the noise is alarming and we are aware of other user complaints about timing chain failure. Despite the obvious nature of this issue, Peugeot avoids replacement here, while in Europe similar vehicles reportedly receive replacements, and we feel victimized by this “avoid replacement” policy. The service spoke to us as if we know nothing and provided excuses that we believe are misleading, even though we are engineers. We also consulted independent mechanics, who confirmed that the sound is consistent with timing chain noise. Instead of masking the problem with thicker oil and sending people home, which could lead to bigger failures, we demand that Peugeot upgrade our vehicle to the 8 mm camshaft/timing chain set the way they do in Europe—without excuses or avoidance. After the service visit, they also stated they could perform additional diagnostics for about $115 if we still believed there was a noise, but on the paperwork they made a misleading statement implying the sound might be caused by something else, as if they had offered a proper recommendation, which we believe is untrue. I request an urgent response.