How quick does your oil turn dark?

OkieFlyer

OkieFlyer

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Andrew L.
I'm a little concerned that my engine oil is getting really dark after only 15 hrs. I use AeroShell W100 in my Continental O-470-R. It's not quite black, but it seems like it should still look fairly fresh at 15 hrs. What say you?

I don't run the engine hot, assuming my gauges are correct. Always in the green on oil temp and CHTs. New oil and air filters.
 
Ours typically takes on a chocolate color by ten hours and looks pretty black by 25. Couldn't tell ya if that's normal but it takes a lot longer in the airplane than my diesel truck. It's black as soon as you start it the first time after you change it. :-)
 
20w50 w/ camguard, 100LL, CHTs never over 380, with a filter, golden brown by 25, black Mid 30s.

Depending on conditions, I'm flying in pretty clean air, for land ops I'm normally on well groomed airports.
 
Thanks guys. This go-round, I have put the 15 hours on in a couple weeks, and 13.8 hrs of it was going to Oshkosh and back. After James331 mentioned ground ops, I remembered how much taxiing I did on grass at Osh. That may be the difference right there.

My CHT's are normally about 330°, I also run camguard, spin-on oil filter, bracket foam air filter, used about 80/20 mogas to avgas since oil change. I'd say the oil is dark chocolate right now, just shy of black.

At annual (about a month ago) I noticed that all the oil didn't drain out. I didn't really pay attention to how much was in the bucket, but when I put oil back in, I only put 7 qts in to bring it up to the 9 qt line on the dipstick. This led me to believe I wasn't getting all the oil out. When I put the fresh oil in and pulled the dipstick, I could tell there was still some dirty stuff in there. Are there any tricks to get it all out? Does some of it stay in the c/s prop? Reckon a little Marvel Mystery Oil an hour or two before oil change might clean up some of the old sludge?
 
James331 said:
20w50 w/ camguard, 100LL, CHTs never over 380, with a filter, golden brown by 25, black Mid 30s.

Depending on conditions, I'm flying in pretty clean air, for land ops I'm normally on well groomed airports.
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yup...same here....just like that. :D
 
OkieFlyer said:
Thanks guys. This go-round, I have put the 15 hours on in a couple weeks, and 13.8 hrs of it was going to Oshkosh and back. After James331 mentioned ground ops, I remembered how much taxiing I did on grass at Osh. That may be the difference right there.

My CHT's are normally about 330°, I also run camguard, spin-on oil filter, bracket foam air filter, used about 80/20 mogas to avgas since oil change. I'd say the oil is dark chocolate right now, just shy of black.

At annual (about a month ago) I noticed that all the oil didn't drain out. I didn't really pay attention to how much was in the bucket, but when I put oil back in, I only put 7 qts in to bring it up to the 9 qt line on the dipstick. This led me to believe I wasn't getting all the oil out. When I put the fresh oil in and pulled the dipstick, I could tell there was still some dirty stuff in there. Are there any tricks to get it all out? Does some of it stay in the c/s prop? Reckon a little Marvel Mystery Oil an hour or two before oil change might clean up some of the old sludge?
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Practice landings. Come back. Open cowling. Wait for engine to cool a bit. Drain.
 
You will never get all the oil out and really, it isn't THAT important to do so. Get as much out a will drain when you're on a flat surface. And ircphoenix has it right, heat it up first. Warm oil drains faster and makes its way down the engine into the sump easier.

Black oil isn't a big deal. Most of it is carbon coming past your rings as part of the combustion process. Worn rings and running rich are both likely ways to get dark oil sooner.

The airplane I fly gets black oil at about 15-20 hours and I run it hard. I keep it leaned correctly even while climbing. It is 3100 smoh.
 
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If your oil isn't getting black quickly, it means the particulates are settling out as sludge, not being kept in suspension to be eliminated when the oil is changed.
 
I use AeroShell 15-50, and Shell's own literature is clear that oil should be changed based on time interval (I change @ 50 hrs), not color. Not sure if that applies to W100 though.
 
GRG55 said:
I use AeroShell 15-50, and Shell's own literature is clear that oil should be changed based on time interval (I change @ 50 hrs), not color. Not sure if that applies to W100 though.
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That's true for any oil.
 
Fearless Tower said:
Might be worth a shot, although I've also noticed the same thing on the Waco (W670) which has less than 100 hours since overhaul and a brand new oil tank.
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Do you actually "change" the oil in a radial? I thought one just added oil as needed, at a rate slightly under that which fuel is consumed.
 
Aeroshell 15-50 turns color quickly. It also promotes breather drool and oil leaks. I switched to Phillips 20-50 a long time ago. The oil remains clean (judging by the color) for much longer and breather drool is reduced. I've never used straight weight enough to know how it compares.
 
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Sac Arrow said:
Do you actually "change" the oil in a radial? I thought one just added oil as needed, at a rate slightly under that which fuel is consumed.
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I do both, but yes, oil consumption is a bit higher.

I typically burn a quart an hour in all three radials.
 
The 182 actually stays pretty clear for at least 20-25 hours, it's hard to see on the stick sometimes! It only uses about a quart per 10 hours or so. On a different note, I've never had turbine oil turn any color. :)
 
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N747JB said:
The 182 actually stays pretty clear for at least 20-25 hours, it's hard to see on the stick sometimes! It only uses about a quart per 10 hours or so. I've never had turbine oil turn any color. :)
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I just assumed we were staying within the realm of piston aircraft engines. Silly me. The John Deere tractors running on propane I used to work on didn't change color either... except that one time it had a golden tint. Should've checked that main bearing better when I rebuilt the engine.
 
I used camguard and it gets dark after about 10 -12 hours. I change every 25 hours. Cheapest thing I do on my plane.
 
Joshuajayg said:
I just assumed we were staying within the realm of piston aircraft engines. Silly me. The John Deere tractors running on propane I used to work on didn't change color either... except that one time it had a golden tint. Should've checked that main bearing better when I rebuilt the engine.
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My 182 is a piston version, haven't seen many turbine 182's a couple of 206's and 210's but no 182's. :)
 
N747JB said:
I put a period between the sentences, but I see how it could be confusing, I'll change it. :)
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No, I'd encourage you trying the turbine oil in the 182. Be sure to stay close to the airport and report back here when you have conclusive results :)
 
Joshuajayg said:
No, I'd encourage you trying the turbine oil in the 182. Be sure to stay close to the airport and report back here when you have conclusive results :)
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Thanks, I stick with putting the turbine oil in the PT6's, it's too expensive to put in the 182 and besides my son took it to college. ;)
 
Fearless Tower said:
Might be worth a shot, although I've also noticed the same thing on the Waco (W670) which has less than 100 hours since overhaul and a brand new oil tank.
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Do you drain and flush the sump? or just drain the tank?
 
Tom-D said:
Do you drain and flush the sump? or just drain the tank?
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I suspect the shop just drained and didn't flush. The shop has to do the Waco since it is on a LOA, and I've only done one change on the Twin Beech so far when the shop was already working on the prop issue.
 
In the Luscombe (C65) it gets really black around 25 hours, when it's time for a change. I add a half quart every 12 hours or so.
 
Thanks for the info guys. Sounds like the dark color isn't that big a deal. I just haven't noticed it going dark that quickly before, but I also usually do fairly short flights and not long XC flights like I did this time, including long taxis on the grass. My oil consumption has been around 1 qt per 6-7 hours or so, as long as I don't have over 9 qts. Anything over 9 qts, and it's all over the belly.
 
Where would I look to check this "oil" you speak of?
 
My mind is somewhat bent when each time I read the title of this thread I keep adding "...on the bedpost overnight"

I must be listening to too many Dr. Deme to re-runs.
 
So, does anybody use a little Marvel Mystery Oil before oil change? I haven't used it in the plane, but I use it periodically in my boat to clean up the sludge buildup. Oil has always stayed cleaner longer after I started using it. Doesn't seem to get contaminated with old lingering oil as soon as I put new oil in. I don't actually use MMO in the oil long term, just dump a little in the pan, run it for a little while, let it sit, them drain. I'm sure MMO in airplanes is a touchy subject, but I'd be interested in opinions.
 
Stewartb said:
Aeroshell 15-50 turns color quickly. It also promotes breather drool and oil leaks. I switched to Phillips 20-50 a long time ago. The oil remains clean (judging by the color) for much longer and breather drool is reduced. I've never used straight weight enough to know how it compares.
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So how exactly does AeroShell 15-50 "promote" oil leaks? :confused: You make it sound as though it's attacking gaskets and seals in an effort to escape confinement. ;)

I have Lycomings. One of the reasons I don't like Phillips oil is because I have to add the Lycoming additive separately. As you top off oil between oil changes it becomes a PITA to keep maintaining the right ratio of additive. I used to run Phillips in my last airplane, and frankly can't tell any difference.
 
Stewartb said:
Aeroshell 15-50 turns color quickly. It also promotes breather drool and oil leaks. I switched to Phillips 20-50 a long time ago. The oil remains clean (judging by the color) for much longer and breather drool is reduced. I've never used straight weight enough to know how it compares.
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I've noticed that the Aeroshell seems to change color more quickly than the Phillips too. I'm sure there is some difference in the additives that are in the oil that causes this but not sure what. At any rate, I never worry too much about the Aeroshell oiled engines turning color fast because I don't think it really means anything.

I haven't noticed much evidence of the breather drool or oil leaks due to Aeroshell personally, but I can't say that it doesn't exist either.
 
Does anyone else notice that aviation oil has a different coloration as it gets dirty... an almost greenish tint to it vs a lot of other stuff or am I just crazy?
 
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