2006 Sentra, 1.8S (QG18DE engine) with 125K miles on the odometer.
In the past, we would not drive more than 3000 miles a year, but since August 2022, my wife started driving it to work, ~50 miles daily round trip.
For the last couple of months, she is complaining that the engine sounds louder, and now for the last week or so, she mentions a faint burning oil smell in the cabin after an hour of driving (At the end of every trip, never in the beginning). I immediately checked the oil level and it is fine. There is no change in how the car drives. There is no engine light. The oil was changed 3 weeks ago with Mobil 1 5W-30. The filter was hand-tightened. Never experienced oil burning before so can't say much. Her first half-hour drive is on the interstate and the rest half an hour is in bumper-to-bumper crawling city traffic.
I pulled out the PCV valve to check if it was busted. While it's dirty, with significant carbon build-up, it rattles. I tried cleaning unsuccessfully with a brake cleaner. Installed back and the engine sounds the same (louder). I have ordered a replacement PCV Valve
. OEM was unavailable locally. I will replace it next weekend.
What else can I check, if anything, or time to call the mechanic?
Thanks in advance.