I finally saw the difference between a 5 year old oil sample and a fresh one

Been doing oil analysis on our JT8D fleet at MRO Tech in Atlanta for years. Last month I pulled a sample from an engine with 3,500 hours since last overhaul and the viscosity was way out of spec, copper particles all over the place. The fresh sample from the same engine after an oil change looked like night and day clear and clean. Any of you guys seen big shifts in metal content after a certain hour mark on older powerplants?

2 comments

2 Comments

leelewis6d ago

Wow, I read somewhere that copper spiking around 3,000 hours is pretty common on those older engines.

reesemoore6d ago

You know, that 3,000 hour mark is interesting, but I've heard the real issue is how the oil was broken in back when the engine was new - a bad break-in can leave copper reading wild for its whole life.