Last week I changed the oil with some "BMW High Performance 15-40" I had laying around that I wanted to use up. It was cold out so it took 15 minutes to add the oil but I have to assume enough had settled in the pan however when I started the truck it seemed to take longer than normal to build pressure, maybe 10-15 seconds before the light went out, and I heard what sounded like an audible scraping for the last second or so before pressure built and extinguished the light. After that the engine was quiet and I thought nothing of it. I checked the level afterwards and it a hair was below the add mark so I dumped some Rotella in to top it off but never checked it again, assuming it would be fine.

Today after about 500 miles since the change I'm hearing an audible scraping that seems to be coming from the front cover and is pretty scary sounding. The engine is an 04 with about 185k on it and until today hasn't missed a beat. Last year I replaced the water and oil pumps when I redid the headgaskets, about 10k miles ago. Oil pressure seems good, the light has never come on (comes on prior to starting so I know it works) and my gauge reads about 1bar at hot idle and 3-4 on the highway, depending on RPM. I think the sender is going however because for the last 2 months it occasionally spikes high, as in pegs for a bit and then settles out. That has not changed with this situation.

Not sure if it matters but I did not fill the oil filter ahead of time, but I haven't done that with this vehicle in 5 or 6 changes and the filter is after the pump anyway so it's unlikely to have affected the pump itself. I think. Has anyone heard of this sort of thing before? I'm not sure what to make of the sound or what could have caused it, it if is related to the pump/cover. Next is to take off the serp belt and see if the noise changes but it sure sounds like it's coming from the cover and I'm more than concerned.

 

Oil pump is probably grinding away at the front cover. Probably due to age and normal wear. I've replaced several dozen of them for just this reason. I'd start with pulling the front cover if you hear audible scraping coming from in there.

 

Before pulling the cover, I would probe around until I found the source of the sound. Remove the belt and run the motor for a bit to quickly rule out the accessories and pulleys. To me, if the pump was bad enough that you could hear it grinding, your pressure would be s***. Your numbers though are on point.

 

Appriciate both responses. I removed the serp belt and Christmas came early. The idler below the plastic tensioner is sloppy and the source of my noise. Despite having less than 10K miles on that idler bearing, the engine is as quiet as can be without the belt on. What a relief...

 

 

Good find. Nice save!