How old does this oil look to you ?
I’ve changed my oil for years. It looks clean even after an hour flight. Very different from after 25 hours. Even when only the oil is changed, and the filter left for the 50h check, even mixing the old oil in the filter doesn’t make it look like the old oil.
Pic means little to me. You’ll have seen your old oil t compare.
Thanks Maoraigh.
I would guess 5-10 hours?
I change my oil every 25 hours and I think it’s dirtier than the picture. The first few hours, you can hardly see it on the dipstick, it’s like Olive oil
What do people think?
Difficult question to answer, but I’d venture to say the oil was replaced alright.
The rate of change of color in the oil is an indicator for the wear of said engine. Worn engines have the oil turn black in a much shorter time, sometimes in a couple of hours, than that in newer ones. Depending how the oil was changed, sucked out or drained, and adding to the oil remnants in the rest of the engine, such as all the galleries, the oil cooler, the vernatherm, the oil hoses, the rocker covers, etc, can result in quite some oil still being in there…
An oil analysis could demonstrate suspect low contamination, but would probably be difficult to almost impossible to use as proof, lest you have a solid history of oil analysis.
Thanks Archer and Dan. Would you expect it to look like this after only a ground run?
On my engine, Lycoming O-360-A1A, 1’100 hrs SMOH, decreasing compressions, increasing oil consumption, maintained by myself, yes. One can say I’m intimate with that engine of mine 
Not sure about yours though, since I have neither reference nor data. From what I can see the oil looks clean, but not pure, fact that could well be attributed to the factors I mentioned above, + a prolonged ground run.
Thanks Dan. It’s that lack of reference which is making this very difficult other than my subjective view that it normally takes quite a few hours to get to this point. However it works out, it’s certainly a good lesson to start as you mean to go on and actually be much more careful to record data and remove the subjective. Appreciate your thoughts. J
I should say it’s an IO 550, SR22 NA 1100 hours. Recently borescoped and found to be in great condition. Consumes a quart 8 hours after oil change, then 7 then six then five and half then oil change again. Been like that since I’ve had her. Always run about 65 degrees LOP. Great numbers – 165 TAS FL120 12.7 gph. 300 cht in cruise never more than 340 in climb except on super hot days.
I take it you didn’t change the oil yourself?
If it normally takes a greater number of hours to take on this colour, my guess is that the oil change was slightly rushed and that they put the sump plug back in before it had completely finished draining. Or they drained if cold. Either way, a small quantity of dirty oil mixed in with the new.
