Mercedes R Klasse Diesel oil pressure and engine noise

Mercedes R Klasse Diesel 2010 oil pressure issue and engine noise I'm experiencing a concerning issue with my 2010 Mercedes R Klasse diesel. The oil pressure warning lamp illuminates intermittently, accompanied by rather alarming mechanical noises emanating from the engine. The car has 297382 km on the clock. Given these symptoms, and considering I'm reasonably mechanically inclined, I've undertaken some preliminary diagnostics. I checked the oil level first, which is fine. I then inspected for any obvious oil leakage, but found nothing significant. After that I replaced the oil filter, suspecting a possible clog, but the problem persists. I'm now suspecting a defect in the oil pump itself, but wonder if engine bearings could also be to blame? Has anyone else encountered such issues? Could it be related to oil viscosity?

4 comment(s)

Low oil pressure and engine noises are never a good sign. I had a similar issue on a 2012 Audi A6. I'd suggest checking the oil pressure with a mechanical gauge to verify the sensor isn't faulty. Is the noise consistent, or does it change with engine speed? If the oil pump is failing, you might also see elevated oil temperatures. What oil viscosity are you using?

Thanks for the quick response. I don't have access to a mechanical gauge to verify the oil pressure sensor unfortunately. The noise seems to increase with engine speed, and the oil temperature gauge reads normal. As for oil viscosity, I've been using 5W-30, as specified in the owner's manual. Should I consider a heavier weight oil, like 10W-40, as a temporary measure perhaps?

Increasing oil viscosity might mask the problem temporarily, but it won't fix the underlying issue and could potentially cause further damage. Given that the noise increases with engine speed, and you've already ruled out a clogged filter, it strongly suggests either oil pump failure or, less likely, worn engine bearings. I would recommend getting it towed to a trusted workshop for a professional diagnosis before running it any further. I ended up having to replace the oil pump on my Audi.

Appreciate the advice. I suspected as much. I'll arrange to have it towed to my local mechanic immediately. Just heard back from the shop: confirmed oil pump failure. Replacing the pump, new oil and filter. Total cost 755€. Thanks again for your help!

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