Fast forward to Redlands Truck and RV's engine assessment.....
Engine using oil: Oil leak at front of oil pan/timing cover gasket. 5 of the 8 spark plugs are oil fouled, engine compression low in 5 of 8 cylinders. Appears to have been an in frame rebuild of the engine possibly. It's possible that the piston rings were improperly installed at time of rebuild. Recommend replacing engine or disassembling to repair issues, if repairable.
Additional notations:
Starter wires hanging loose
Left exhaust manifold leaking at head, both manifolds leaking at pipe connection
Spark plug wires melted
Bottom line, Serenity is getting a new engine.