Oil consumption?

fiveoboy01

fiveoboy01

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Dirty B
I'm at 50 hours on the new engine. Runs great, but the oil consumption seems up there, using a quart every 5-6 hours.

For the first 10 hours it was ran at high power settings, very minimal idle time, etc... After that reverted to more normal operation per the builder's recommended break in procedures.

I keep the level at 6 quarts and when it gets to 5, I add one. I was advised there is no need to run more than 6, any more than that and it goes out the breather anyways.

Added a quart at the following intervals(starting with zero time):

5.6
2.6
(changed oil at 10 hours)
10.1
7.9
8.2
9.1
5.4

I've got 3.6 hours since the last quart was added and it's looking like it will be down to the 5 quart mark after another 1.5 or so.

A quart every 5-6 hours cause for concern? Too soon to worry about it? Still running Type M 20W-50.
 
Still early

How big is the engine?

Most manufacture have a equation for max allowable oil consumption, also remember most all engines will blow off a qt or two of oil and their default happy place isn't completely topped up.
 
Ask the builder and read what Lycoming says, if that's what it is....
I'm up to 90 hours on my rebuild and I use 1.5 quarts every 25 hours.
But then Geico told me I was destroying my new engine so what the hell do I know? Best wait for him and his groupies to learn ya!
Sound like the rings didn't seat on one or more cylinders. Check the exhausts.
Good luck.
 
James331 said:
Still early

How big is the engine?

Most manufacture have a equation for max allowable oil consumption, also remember most all engines will blow off a qt or two of oil and their default happy place isn't completely topped up.
Click to expand...

O360A4M.

I'm also inclined to think it's early but the increase in consumption has me a bit worried.

I guess I could let it run down to 4 and see..

I wrote the last interval off as a fluke but now it looks like this one will be the same.
 
Did a top overhaul few years ago on my O360A3A. Burned straight mineral oil first 10 hrs with an oil change at 5 hrs. Switched to 20/50 camguard at 10 hrs. Flew the snot out if the plane. Rings seated by 2 hrs as evidenced by substantial drop in CHTs. Oil consumption was up there through 5 hrs but normal since then, now usually a qt every 15 or so hrs. Your consumption seems a bit high, but like previously said, talk to the rebuilder. Do you have an engine monitor that shows each cylinder's CHT-EGT? If yes, is there an outlier? If no, recommend you bite the bullet and install one. You can always simply borescope each jug and take a look see. Any oil leaks? Have you changed the oil filter and cut it open to take a look?
 
I'll second a good engine monitor, not just for this, but it's really a very important piece of saftey and diagnostic equipment, even more so in a single engine.
 
It's not uncommon for the 4 cylinder Lycomings to burn a quart every six hours or so.
 
I do have a 4 channel CHT/EGT.

No anomalies, except #3 likes to get hot. It would go to 450 in a climb on a hot day if I let it. Baffling has been checked and is ok. Installing a modified winterizarion plate helped though. Level cruise flight the temps are all normal across the board, 350-370 or so.
 
Diffrent engine, but if I saw anything near 450 I'd be doing some research becuse that's not good.

My personal max climb CHT for my io520 is 380, max cruise is 350.

I don't think I've ever seen 400, and I still bought a cowl louver kit.

How the plane performing compared to book numbers?

How the oil temp and pressure?

I'd do some more digging, maybe find another AP for a second look, and bring them up on a test flight with you, also finding some owners of the same type and comparing notes would be great.
 
Oil temp is fine. Pressure is close to 100 cold, warmed up it sits around 60-70.

Plane performs fine, 1000 FPM this morning with almost full fuel and 400 pounds of human, field elevation 850 and about 65-70 degree temps.

I've thought that the probe might be reading incorrectly. The rest of the cylinders will read 390 or so in the same situation.

Pulled the lower cowl, the starter is wet on the bottom with oil as well as the front of the pan. Looks like some oil on the top of the muffler shroud too. So it may be a leak, rather than consumption.

Would be a better explanation for the sudden need to add oil more frequently.
 
For what it's worth, cylinder #3 always seems to run the hottest on the o-360s. If there is a cylinder that doesn't make TBO on an o-360, it will probably be #3.

Also, like I said before, 4-6 hours per quart of oil is not uncommon. Consumption usually starts out lower after a fresh oil change and rises the longer you run the oil. In your first post you say nothing about a sharp rise in oil consumption yet in your most recent post you claim it recently started? While being messy I have my doubts that your oil leak is a significant contributor.
 
fiveoboy01 said:
Oil temp is fine. Pressure is close to 100 cold, warmed up it sits around 60-70.

Plane performs fine, 1000 FPM this morning with almost full fuel and 400 pounds of human, field elevation 850 and about 65-70 degree temps.

I've thought that the probe might be reading incorrectly. The rest of the cylinders will read 390 or so in the same situation.

Pulled the lower cowl, the starter is wet on the bottom with oil as well as the front of the pan. Looks like some oil on the top of the muffler shroud too. So it may be a leak, rather than consumption.

Would be a better explanation for the sudden need to add oil more frequently.
Click to expand...

Take a close look at the crank seal. I've seen the wrong one instaled before.
 
Gotta love those Rotax... never had to add a drop between changes. 650+ hours, in two different aircraft.
 
CT4ME said:
Gotta love those Rotax... never had to add a drop between changes. 650+ hours, in two different aircraft.
Click to expand...


Just like my B&S powered lawn mower.

And just like my mowers engine, I doubt even the mighty 100ish HP rotax would even get most of the full sized certified fleet off the ground, probably wouldn't even get my 185 up on step.
 
Last edited:
mondtster said:
For what it's worth, cylinder #3 always seems to run the hottest on the o-360s. If there is a cylinder that doesn't make TBO on an o-360, it will probably be #3.

Also, like I said before, 4-6 hours per quart of oil is not uncommon. Consumption usually starts out lower after a fresh oil change and rises the longer you run the oil. In your first post you say nothing about a sharp rise in oil consumption yet in your most recent post you claim it recently started? While being messy I have my doubts that your oil leak is a significant contributor.
Click to expand...

It was previously using a quart every 9-10 hours. It's needed a quart every 5 or so hours for the past 10 hours. Sorry if my post was confusing.

I don't think the leak is where it's going either. If I was losing a quart in 5 hours the entire engine compartment would be an enormous mess.

I'm going to continue to monitor it and see what the next 10-20 hours bring. It's due for an oil change in 10 hours. If it continues I'll get my A&P to take a look. Trying not to be overly paranoid... But it's tough when the engine **** on me after 95 hours and I just paid for a full overhaul.

I too have heard that #3 runs the hottest of the 4, at least climbing and at high power settings.
 
CT4ME said:
Gotta love those Rotax... never had to add a drop between changes. 650+ hours, in two different aircraft.
Click to expand...

My dad has a 912is in his airplane, it's been a great engine. But I wanted a little more speed and payload. They do have their place.
 
fiveoboy01 said:
It was previously using a quart every 9-10 hours. It's needed a quart every 5 or so hours for the past 10 hours. Sorry if my post was confusing.
Click to expand...

I see what you were trying to say in the first post now. It looks like you're running the oil change out to 50 hours, right? If so the trend you're seeing of consumption increasing as you get closer to an oil change is pretty much what I've seen. Based on oil consumption rate alone, I see no reason to be worried about anything yet.

fiveoboy01 said:
I too have heard that #3 runs the hottest of the 4, at least climbing and at high power settings.
Click to expand...

The majority of the o-360 cylinders I've removed for rework or replacement have been #3. I seem to recall Tom-D saying the same thing around here too. There definitely seems to be a trend there.
 
Why are you still running M? The first thing I'd do would be to switch to X/C or Aeroshell 100 Plus and watch it to see if a different oil behaves differently. At any rate its time to use AD oil.
 
To clarify on the oil change intervals, I changed it at 10 hours, then 35, per The builder's recommendation. Interval is 25 hours(personally set by me), so the next one is due at 60(tach is at 51 now). Manual that came with engine said "switch to AD oil at 60 hours, or when oil consumption stabilizes". That is why I am still running mineral oil.

At that time I'll switch to what I used before the rebuild(Exxon Elite Synthetic).

I updated my spreadsheet today and it's a nit pick, but it was 6.1 hours to the "quart low" mark this time.
 
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