Hi I have a L2900 GST DT. Over the summer Mud Daubers (wasps) built a fairly large nest in the air filter housing. This fall when I started the engine, most of the nest went into the engine through air intake. I have flushed the engine oil 3 times using diesel oil motor flush and fresh oil each time. While I can't see any contamination, I'm not so sure it isn't there. So what are my chances of removing the sand if it's still in the oil or should I plan for an engine rebuild?