I took some pics and disassembled my double row IMS bearing tonight. When I was doing the job a LOT of old nasty oil came out of the tube, easily more then a cup. I'm thinking how the heck did that get in there. I figured it must be coming from the far side because the bearing looked like brand new. Well as I took the bearing apart I discovered the reason, oil was making it past the bearing seal freely, the bearing was full of fresh oil. The oil in the bearing was a lot cleaner then that I found in the tube.
There is no way any grease packing in these bearings would ever hold up, my bearing was lubricated solely on engine oil. It's almost like I could have taken the seal off, expose it to engine oil and just left it in. The LN bearing is like this, seems like the correct design to me. I can also see why making sure your oil is fresh and clean makes sense. It would also make sense to me that the more mileage on a car the less bearing failures one would see, I say this because it would seem oil would more easily move in and out past the seal into the bearing as it ages.
I took as much apart as I could, my bearing was strong and seems it could function even if it was missing the bearing guides. No bearing pitting at all. From what I can see if all forces on the bearing are equal and balanced that the only way these things could self-destruct is if pitting occurred.
