The issue may lie with the oil solenoid itself, which could be worn internally. The link below contains extensive information on the B48 engine, which shares a similar design but is missing one cylinder compared to yours. It illustrates the solenoid bolts and how the gauze fails; when it does, it directs the gauze towards the sprocket. It is unlikely for it to move in the opposite direction, as oil pressure ranging from 40 to 80 psi propels it one way. To be candid, the B series engines present significantly more challenges during maintenance. The vehicle referenced in the link adhered strictly to the manual, except for the injector replacements. Upon removal, the owner noted a fuel odour and observed a mark on the injector seat to rail. BMW typically replaces the injectors when servicing chains. A colleague at BMW expressed surprise that I managed to extract all four injectors without breaking or damaging them, as each required careful handling and took approximately an hour to remove gently. This vehicle had 118,000 miles; the chain was worn, and the sprockets were in poor condition. The timing ring on the inlet cam was discovered to be loose when heated, resulting in the erosion of the location groove. Additionally, a coolant leak was identified due to the degradation of the plastic oil filter housing caused by age and heat. A colleague at BMW mentioned that the normal cost for chain replacement is approximately $4,000. The last one I completed was half that amount, utilising original equipment parts from INA. INA is imprinted on authentic projects adjacent to the BMW stamp. The INA full kit from Mpd is priced at about fifty percent less than the equivalent kit from BMW, although including identical components manufactured in the same location.