Is this oil loss excessive?

[AndreiC]

Question: how much oil coming out of the air/oil separator is too much?

After landing two days ago after a long (5.5 hours) flight, I noticed that the gear doors on my 70E (IO360) are quite dirty with oil, especially the left side one. I attach a picture, with a comparison of the right (exhaust side) one; the gear doors were cleaned completely about 12 hours ago. It was enough oil so that one small drop fell to the ground in the place where I was parked. Checking the oil level, I think I lost/consumed about 0.75 quarts on this 5.5 hours flight. I did not open up the cowling to check inside, but it seems the dirtiest it is around where the line from the air/oil separator comes out of the cowling.

I am not sure, but the amount of oil consumed seems to have increased somewhat. The first 20 hours after the oil change I did not seem to use almost any oil at all. But the following 10 hours used about 2 quarts, more or less. Here is a log of oil level since the last oil change:

-- at 0 hours since oil change, I was at 7 quarts;

-- at 20 hours I was around 5.5 quarts, added 1 quart;

-- at 25.5 hours I was at 5.2, added 1 quart;

-- now at 32 hours I am at 5.5.

Is this something to be concerned? Can I do something to reduce the oil blowing out?

 

 

[natdm]

What's the minimum oil your POH says you can fly with?

Seems like you're putting in a lot of oil, maybe too much.

A quick search says that engine can go as low as 4qts, which seems scary. If it dipped below 5, I'd be curious. 

I have a completely different plane and engine but I know the max oil is 8. If I put 8 in, it's gone pretty quick. If I put 6.5 in, I notice it hovers there until the next oil change.

 

[dzeleski]

I ended up removing my separator because it was causing more issues then it was helping. One reoccurring theme that I had though was the position of the tank is critical, if the oil cant easily drain down into the cylinder drain tubes it will just over flow and make a mess.

[mike_elliott]

The io360 likes to settle at 6qts and seems anything above that, your better off just wiping it on the belly and avoid the middle man. Personally, I am not a fan of dumping oil full of combustion acids and moisture back into the engine like a separator does, YMMV

[AndreiC]

Interesting. The oil change was done by Top Gun, and they put in the 7 qts. My general philosophy was to keep it above 6 qts, and whenever it dropped below that I would add a quart. From what people are saying here it is wiser to keep it between 5 and 6, and add when it dips below 5?

Also, I did not know that air/oil separator was an optional item. Are there more people out there who don't like it, and prefer to just blow the stuff out?

[Fritz1]

yes, do not fill above 6 qts, keep between 5 and 6, take separator off and see what that does

[Fritz1]

there are pros and cons for the separators, some cause more trouble than they are worth, think the best one is the air wolf, heavy and expensive though

[EricJ]

9 minutes ago, AndreiC said:

Interesting. The oil change was done by Top Gun, and they put in the 7 qts. My general philosophy was to keep it above 6 qts, and whenever it dropped below that I would add a quart. From what people are saying here it is wiser to keep it between 5 and 6, and add when it dips below 5?

Also, I did not know that air/oil separator was an optional item. Are there more people out there who don't like it, and prefer to just blow the stuff out?

I put it at 7 right after a fill as well, and you showed that yours still took 20 hours to use 1.5 qts, which isn't bad at all.    After the first fill after a change I tend to try to keep it at 6 qts, but going over that for a long trip or something still works pretty well.

It might be worth opening the cowl up to see if you've developed a leak somewhere, or if the oil is really coming out of the separator or somewhere else.    Normally excess or aerated oil goes out the crankcase vent tube and onto the belly, and oil that gets on the gear doors is from a leak somewhere.    I'm not sure how your separator is arranged, but that may be worth looking at.

[LANCECASPER]

If I was you, on a long cross country like you did recently, I wouldn't mind an extra quart in there for peace of mind. It might buy you an extra minute or two before things seize if you are dumping oil for some reason. Also our engines are both air and oil cooled.

But in normal use I would try to keep it at six when you start up for the day. Don't check it an hour or two after a flight. Wait until the next day or the next flight and see where it has settled. If you check it soon after, it might be a 1/2 to a full quart lower than it will be the next day. If you add a quart right after a flight, on the next flight you might just be blowing out oil that never should have been in there.

Has the air oil separator and the lines going to and from it ever been cleaned? That would be where I would start. Cleaning it might lower some of the  pressure that's blowing it out.

Also cleaning the engine and cowling completely might reveal other oil leaks that could be handled with new gaskets.

[201Mooniac]

Top Gun will always put 7 quarts in the IO-360.  I don't have any leaks currently and my air/oil separator seems to work well.  I try to keep my oil above 6 quarts most of the time but never fill beyond 7 so I typically wait until I get to a little below 6 and then add a quart.  Typically about 1 quart in 12 hours or so.

[Echo]

I agree with responders Andre.  If I add above six quarts (Always measuring when oil is cold) It just blew out the oil.  I add to maintain six quarts at all times before flight.

[MikeOH]

Piling on with run it at no more than 6 qts.  FYI my 2600+ hour engine goes through 1 quart every 7 hours...so, I'm jealous of your usage!

I've been very happy with my separator and maybe all those recycled acids and junk have allowed me to get to 2600 hours

That oil on your gear doors definitely indicates a leak somewhere... I'd be going nuts if my gear doors had oil like that all over them!

[Shadrach]

6 hours ago, EricJ said:

I put it at 7 right after a fill as well, and you showed that yours still took 20 hours to use 1.5 qts, which isn't bad at all.    After the first fill after a change I tend to try to keep it at 6 qts, but going over that for a long trip or something still works pretty well.

^^^^this my SOP. Initial fill is a little under 7qts to leave room for a bottle of cam guard.

[Justin Schmidt]

I never see anything out of my separator. I put in 7qts + camguard. Burn 1 qt every 10 hrs

[carusoam]

Surely the original design of the oil/air separator doesn’t allow for spreading any oil as shown in the pic…

Variations in installations have shown that overflows occur under certain circumstances…

the purpose of the oil sep… is to keep oil from escaping the case vent.

the I and O360 have a tendency to let oil out the vent when filled above 6qts, climbing, at high power… lots of pattern work can result with lots of oil on the belly…

the vent has a tube where the oil drops are set free under the belly…

When excess oil has a tendency to show up dripping off the tail tie down… this is a sign of extra positive case pressure, blowing oil out the vent line…

if your oil is foamy, black, and smells like exhaust… and only has 10 hrs on it… you might have a ring problem…

see if running a quart less oil stops the flood… too low oil level will be shown as too high of an oilT… (land and add quart back in…)

keep in mind… without the sep, the oil drip problem was a small pain. Nobody would add a sep to get a bigger pain…

Ancient PP memories only, not a mechanic…

-a-

[GeeBee]

When ever I see a dog eat its own vomit, I think of the air/oil separator.

 

[AndreiC]

The oil that comes out is not foamy at all. In fact I thought I even saw a rather yellowish, nice looking oil dripping. Only a tad darker than it came from the bottle. In fact I was congratulating myself on how clean the oil looks on the dipstick even after 30 hours.

I'll probably open up the cowling tomorrow to see if I can see other places it may be leaking from.

[MikeOH]

Check rocker covers, oil drain back fittings, oil drain back hoses (between metal drain tube and fitting on crankcase), oil filler tube gasket.  I've chased all of those.  Also, could be something on the back of the accessory case (mags, oil filter adaptor, governor) but it's pretty hard to clean/see those potential sources.  Good luck!

[Fritz1]

Clean suspect areas real good with mineral spirits, dust with baby powder or white developer for dye penetrant system, fly for 30 min, take off cowl, look for oil traces