GLC Oil Pressure Warning and Engine Noises

The symptoms you describe certainly sound concerning. I own a GLC as well, and I had a similar experience some time ago. The low oil pressure light, coupled with unusual engine noises, is definitely something to take seriously. In my case, it turned out to be a faulty oil pump. Before condemning the pump outright, though, have you noticed any significant oil leakage? That could also contribute to low oil pressure. It's worth checking the oil pressure sensor as well, although that's less likely to cause the noises you're hearing. What kind of oil have you been using, and how often do you change it?

Thank you for your insight! The oil leakage situation is unclear, I have not been able to properly check this. Regarding the oil, I have consistently used the oil recommended by Mercedes, and I adhere strictly to the service intervals outlined in the manual. Could you perhaps elaborate on the mechanical noises you experienced? Were they similar to what I'm hearing now?

Yes, the mechanical noises were quite similar – a distinct rattling and knocking sound, especially noticeable at lower engine speeds. Given that you've maintained the oil changes diligently and are using the correct oil, a defective oil pump does seem like the most probable cause. With those noises and the low oil pressure light, continuing to drive the vehicle could cause significant damage to the engine bearings. I strongly suggest taking it to a qualified Mercedes workshop as soon as possible. They can perform a proper diagnosis and confirm the source of the problem. Ignoring it could lead to a much more expensive repair down the line.

Thank you again for your invaluable advice. I followed your recommendation and took the GLC to a trusted workshop. After a thorough inspection, they confirmed the oil pump was indeed defective, just as you suspected. The repair cost, including parts and labor, amounted to 755€. I am grateful for your help!