IO 540 oil use

[Westberry]

When I top off my oil at 8 quarts, I seem to go through 2 quarts with in 2 hrs. and then run on 6 quarts for many hrs. before topping off again.
There isn't any sign of a leak and the compression is in the high 70's.
What is happening to the first 2 quarts?

[LT4247]

It "blows it out". The first quart and a half collects on the belly..
It is just the way it is and I can't explain why. I got tired of cleaning the belly so our IO-540 235 is run with the oil stick showing about 6 1/2 quarts.

We add about a 1/2 quart every 4 or 5 hours. Anymore than that and it just gets wasted. I am sure there are owners/pilots here who can tell you technically WHY this happens. All I know is that OUR IO-540 likes a little less oil on the stick and it seems normal.

We use Aero Shell 15-50 year round.

[andy]

Don't know about the O-540 but my O-360-C1F likes 6.5 quarts the best. It doesn't blow out excess oil at this level. I don't let the oil get below 6 quarts. If you fill it to 8 quarts, you are guaranteed to have at least one quart blown out the breather tube onto the belly. I add 1/2 quartt every 4 hours or so depending on the type of flying. More oil is burned at high power settings like takeoffs. I use Aeroshell 100+ above 50 F average temperature and 80+ below that point. AMT opinions vary on the use of 15W-50. Some of them don't think it lubricates as well as straight-weight and others think it's wonderful. Either is ok with Lycoming.

[TomD]

Depending on what tires or if you are on floats the oil indication will vary.

On floats my 0540J1A5D likes to run with about 10.5 qts indicated.

On 6.00 tires indicates about 10 maybe a little less

On 8.50's it will blow anything out that is indicated above 9.5 qts.

At oil change put in a known amount of oil ( allow for filter capacity ) and check your dipstick to get a real reading.

TD

[Westberry]

Thanks Guys, it is good to know this is normal. I want sweat flying on 6 qts anymore, or cleaning her belly, but I will continue checking before each flight.[/i]

[BudG]

I might have misread the subject....you were talking about an IO-540? Anywho...The dip stick on my io shows 12qts. to be full. I, like many others run it about 10qts. I was told as a nubee that lycomings just puke the first two qts. out on the belly, no matter what displacement. I will attest to that. But, my point being that you mentioned that you were running it at 6 1/2qts. That seems to me to be way to short on your coolant. Probably just a typo or I'm having a senior moment, and if so just disregard. I love those 540's and wouldn't want one to be thirsty.

CAVU2U
Bud

[maules.com]

Lycoming O360 C1F and C4F 180 hp is 8 quarts
O540 J1A5D and B4B5 235 hp is 12 quarts
IO540 W1A5D and W1A5 235 hp is 8 quarts
If your dipstick shows different, you have the wrong one.
Lycoming advises that minimum safe oil level is 2 quarts, however I would not go anywhere near that low.
All should have the Lycoming Engine operators Handbook which has masses of important and interesting information to learn about your engine and to enable flying safer plus extending operating hours on your valuable asset.

[BudG]

Wow, thanks Jeremy. Very interesting to say the least.

CAVU2U

BUD

[BudG]

You got me to do some investigating. The possible explanation on why I have a 12qt dipstick is; A previous owner lived in southern Texas. Years ago a 337 was done for a second external oil cooler, I presume for the extreme heat. The cooler is also equipped with long lines.
The stick must have been replaced with the one indicating 12qts so the operator would have a fudge factor without having to think about it. I run it at 10qts. and the oil use is stabilized. That would account for the 8qts. and two more for the other cooler and lines. I shoulda hada V8.
OBTW I'm ordering the covering material and paint for my bird today. I'm told that we can stick with the present cowling, Jeremy. Thank you Sir.

Thanks to the original question and for the answers. Great web site.

CAVU2U

BUD

[a64pilot]

No matter how many coolers or extra lines you have, the level in th eoil pan shouldn't change.
Of course if you added two quarts of extra cooler and lines, you would hold two quarts more, but still have the same level on the oil stick.
Two quarts of cooler and lines would be a huge cooler I would think?

[BudG]

more investigation I presume Dr. Watson.......

CAVU2U

BudG

[aero101]

If it's an 8 qt engine, when I changed the oil, I'd put in 7-8qts, run the engine which will fill the coolers, lines, etc and shut down / immediately recheck oil level... 2 qts extra for even dual oil coolers and lines seems like too much to me, maybe an extra half quart to 3/4 quart would be more reasonable? I think you'll find less oil blowing out at 6 1/2 to 7 qts range, but you do need the proper stick as everything changes on the 12 qt stick (or fill to 6 - 7 & 8 qts and check or remark stick as needed), and I'd rather be slightly below full then overfull as that's hard on seals, accessory case gaskets, vent system, etc, etc.... Worse case at 10-12 qts could cause blowing out of front crank seal especially in cold WX. Not a pleasant experience!!

[BudG]

Thanks for the good poop!!! I'm going to make the change and just make note on my dip stick by doing the empty-fill method. I sure wouldnt want the poor overstuffed baby to puke at 200ft on takeoff. Ugly thought!
Have a Merry Christmas.

CAVU2U
BUD