GLK oil pressure warning and maintenance concerns

I understand you are experiencing difficulties with your Mercedes GLK. A similar situation occurred with my own GLK, concerning the engine oil. Have you inspected the engine oil itself for any signs of degradation or the presence of foreign matter? Is the oil level within the correct range? An exceeded maintenance interval can indeed lead to oil sludge formation and subsequent contamination of the engine oil, potentially triggering the warning lights you described. Was the correct grade of oil used during the last oil change, and was a genuine Mercedes-Benz oil filter installed?

I did check the oil level; it seems okay. I have not really looked closely for sludge, though. I usually go with whatever's recommended at the parts store for the oil and filter, but I do not think it was a Mercedes-Benz oil filter. Could that really make such a difference, or would I have spotted the issue earlier if that was the case?

The use of a non-genuine oil filter, while seemingly innocuous, can indeed contribute to the problem. The filtration efficiency of aftermarket filters can vary significantly, potentially allowing finer particles to circulate within the engine oil, accelerating wear and contributing to oil sludge. Considering the symptoms you describe, and the mileage of your vehicle, it would be prudent to have a qualified technician inspect the engine. A comprehensive assessment will determine the extent of any potential damage and the necessary remedial actions. I advise you to seek professional assistance without delay.

I took it to a workshop, and you were right; it turns out I was overdue for an oil change. They did a full service, new oil and filter. Cost me 165€, but at least the warning lights are gone now. I'll definitely be more careful with the maintenance schedule and use the correct parts next time.