Oil Color

RyanB

RyanB

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Just how fast after you change your oil does the color begin to darken?

Right after it’s changed, it can be difficult to see the oil level on the stick, it’s so clean. I’m at just under 9hrs on this oil and it’s taken on a golden-yellow color. Seems to hold a similar color until 30hrs or so and then begins to get quite dark around the mid-30’s and 40’s.

What about y’all? At what color rate change should you be concerned? Oil is Shell Multigrade FWIW.
 
I change oil and filter at 25 hours. Stays a nice golden color.
 
I change between 25-30 hrs. That’s just coincidentally around when it gets to take on a flight school darkish blackish hue.
 
Ryanb said:
Just how fast after you change your oil does the color begin to darken?

Right after it’s changed, it can be difficult to see the oil level on the stick, it’s so clean. I’m at just under 9hrs on this oil and it’s taken on a golden-yellow color. Seems to hold a similar color until 30hrs or so and then begins to get quite dark around the mid-30’s and 40’s.

What about y’all? At what color rate change should you be concerned? Oil is Shell Multigrade FWIW.
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If you are using AeroShell 15W-50 it has an ashless dispersant additive system. The color is not relevant. The time (hours flown or calendar time if the plane sits) is what governs.

From the Shell literature:

Why does oil turn black between oil changes, and why does the time it takes to change colour vary?

When a straight mineral oil turns dark or black, it usually means that the oil is starting to oxidize and needs to be changed. Because mineral oil doesn’t absorb much of the dirt and sludge in your engine, the oil stays clean and the inside of your engine gets dirty. Ashless dispersant oils, on the other hand, are designed to get dirty so that the engine will stay clean.

Just how quickly the oil turns black depends on a number of factors, including the condition of the engine, the dirt load, the oil temperature, the normal air/fuel mixture, the type of fuel, the time since the last service, and the frequency and duration of your flights. Basically, the important thing to remember is to change your ashless dispersant oil on calendar and engine time, not according to its color. Also, oil analysis can help ensure that the oil is still in good condition even though it may have turned black​
 
I wish my hair was like the engine oil. Seems that 30's and 40's is when it got lighter in color, as opposed to darker. I change my hair at least once a year (shave my head in March) and is still comes back the same gray.

Am I missing something?
 
Ravioli said:
I wish my hair was like the engine oil. Seems that 30's and 40's is when it got lighter in color, as opposed to darker. I change my hair at least once a year (shave my head in March) and is still comes back the same gray.

Am I missing something?
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Only if it's straight mineral grade. ;)
 
If you want to see oil darken in record time, get a 3rd-gen commonrail Cummins Dodge Ram...my oil would turn black in the time it took to pull off the ramps and down the driveway to check the dipstick following an oil change...
 
I’m in the 25-30 hours group, except when on long cross country trips. I can’t fly Florida to California and back without exceeding 30 hours, but it’s not sitting and I think that’s the key. If I’m scheduled to be down for maintenance or upgrades I will try to change the oil beforehand even if I haven’t reach 25 hours.
Roughly speaking, oil is hard to see for first 10 hours, clear but golden for next 10, opaque and darker golden for next 10, and then dark brown to black.
I run LOP if it matters.
 
The official recommendation is, with a screen filter 25 hours. With a screw-in oil filter 50 hours. I have a screw-in filter and change every 35 hours. Oil is cheap, engines are not.
 
Aeroshell 15-50? Turns color in a couple of hours. Phillips X/C? Barely changes color during an oil change cycle. Both are AD oils. One is semi synthetic. Try it for yourself.

Currently using Aeroshell 100, so not brand biased. I am performance biased.
 
DFH65 said:
You need a plane that uses more oil then it has a constant supply of fresh.
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I once owned an old Mk I Jetta as a winter beater, that car ate a quart of oil every 500mi, so I kept a case of whatever was cheapest in the trunk and spun a new filter on every 3kmi. I considered the oil self changing.
 
I log my oil change as soon as it changes color because I know I'm going to do one soon.




Okay, that was a bad joke off the "clear of runway" threads.
 
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