Hi everyone it has been a little while since on site last. I own a 2004 Cat 303 cr excavator I use for personal use only. I do all of my own upkeep (oil changes. filter replacement etc...) Last year I notice that the oil was very black while check level and then did oil and filter change. I checked level after change and seen that the fresh oil I put in turn black also. This year changing my oil same thing, turned black with no run time on the machine. As stated I use this for my own personal use so I put very little hours on it (approx 50hrs or less). Not sure if this is common or should I be worried? I also own a Kubota 3130 tractor with same size engine ( 30hp) and the oil in that is as clean as the day I put it in the tractor after 100 hrs of run time. Any helpful hint will be appreciated. Gary
Oil has a detergent in it to clean & lube. It's nothing to worry about, just keep up your maintenance. My auto mechanic's teacher back in the 70's always said oil turning black means it's doing its job It does seem that the oil in the newer engines turns black a lot slower