I am experiencing difficulties with oil pressure upon start up and I am thinking that somehow I may have lost prime in the oil sump. Upon start up, the engine sounds freakin awful for about 2-5 sec depending on how long it sits. Clattering, knocking, tapping, etc. The oil light remains on for about 10 seconds as well, while all other indicators are not illuminated. After this 5-10 sec period it seems to "grab", smooth out nicely, and the oil light vanishes. Truck runs great afterwards. I just changed the oil last night and substituted a quart with Lucas oil stabilizer and a quart of Marvel Mystery oil, which by the way seems to really quiet and smooth the engine. But, Im still seeing some noise (less than before) and the oil light for a short time. Do these things sound sump prime related? If so, how does one reprime the sump on a 98 D1. Truck has 77k, by the way. Thanks.