Oil Excess Venting Level

Hi. I understand topping up the oil on a Cirrus SR22 much above 5 on the dipstick leads to the excess being vented down the underside.

With mine, i find that it seems to vent oil down to around 4 quarts. I am uncomfortable launching with anything below 5 on the dipstick so it is leading to a lot of cleaning of the underside.

Does anyone else find theirs venting down to 4 quarts or are there any tip to keep more oil in the sump? CLimbout for me is no steeper than the autopilot wants to go. 4 quarts seems awfully low.

No. No. No

Calibrate the dipstick

Perform a crankcase pressure test.

What you are describing is so wrong.

4 Likes

Get your plane into a Shop that knows a thing or 2 about cirrus.

What Jim said is true.

Okay thanks will get them to check. It is serviced by the largest cirrus workshop in the area that do maybe a dozen of them a week so presumably they know a thing or two, and i have mentioned it. They said normal to vent above 5 quarts on climbout. But will get it rechecked.

OKay update on that after talking to the shop. They do compression checks and boroscope and that would reveal if crankcase was pressurizing and its not. So they arent too worried about that. A “dipstick calibration”… they were a skeptical of this suggestion which i can understand.

They say its quite common to vent oil down to 5 quarts. Mine will keep venting below 5 quarts. They are often fitting breather extensions which helps stop the oil foaming in the crankcase apparently. Will try that first.

CMI has a nice spot in the MM regarding crankcase pressure.

That possible issue can cause
oil to vent overboard uncontrollably…

Oh,

There is an NTSB report on someone who flew the airplane onto a levy sort of road in Florida who also went by a low oil quantity was OK thought…

N444VR

Look it up.

Oh,

Its worth the $65 to join up and read about that incident and the oil dipstick calibration process.

R

Jimmy

2 Likes

Well, they’re far from accurate so a calibration makes sense. At eight quarts, mine reads one quart high — that is, eight quarts in the sump indicates top of the “8.” I run with eight quarts in the sump (which means adding nine at oil change with the -109, one quart filter) and blow exactly nothing out. At the end of 25 hours I have what I’d describe as an imperceptible residue on the belly. @Jim_Barker installed AOS.

1 Like

Thanks all. The engine is quite new (250 hours) and the compression pressures are normal for that. I suppose that is why he doesn’t think it would be crankcase pressure. Also of course new from factory so i would have thought that Cirrus/Continental would have the dipstick calibration reasonably well sorted. We will try the breather extension and il report back.

By the way, how much oil are most people typically using? I see online they say about a quart every 3 hours.

You really should join COPA for up to date information.

A quart every 3 hours is just crazy. I (and many of us) get 12-15 hours per quart.

And my dipstick reads 7 when there are 8 quarts in the engine, 6 when there are 7 etc. I fill to 7 on the dipstick (8 in the sump) , add a quart when the level gets to 6 on the dipstick. Yes, there is a little oil on the belly, but there’s plenty of oil where it matters - in the engine!

5 Likes

Okay fair enough…just quoting wesbites written by people who also seem to know their stuff. https://www.aopa.org/news-and-media/all-news/1999/march/pilot/a-hard-decision-to-top

You asked “By the way, how much oil are most people typically using?” and then suggested the AOPA article answered that question.

I think you misunderstood the line in that article “In fact, most mechanics would rather the investigation start when the engine burns more than a quart every three hours.”

That’s hardly saying most engines use a quart every three hours!

That line certainly does not answer for “most people”

My SR20 had all 6 cylinders redone about 200 hours ago because the oil consumption had rather suddenly dropped to a quart every three hours and then within another few hours was consuming a quart every hour.

Since the cylinder rework, my plane has been burning about a quart every 20 to 25 hours.

Exactly…so mine is using less than when they suggest starting the investigation but i anyway… I am continually amazed at the pedants on forums. Il will leave this one to the service centre i think from now on. thanks to the earlier respondents for some things ot look for.

I apologize. I was not trying to be pedantic. I honestly thought you believed a quart every three hours was typical or normal for these engines.

One of the biggest challenges of airplane ownership is the variation in the aptitude of A&I’s who work on our airplanes. The smart ones who’ve learned the hard way don’t want to give their knowledge away, the not as smart ones don’t admit what they don’t know (which is sorta tough regardless) and the parts chargers who know a little will tend to hold their hand out until the owner is out of money. Avoiding the endless loop of differing opinions and staying safe makes this not so much fun sometimes.

1 Like

Jeff:
That may be true some places but we have too many exceptions to say that is a general rule. We have an excellent group of mechanics that participate right on these forums that liberally give us their knowledge and wisdom. And, because of the education from the good mechanics out there, it is easy to spot an uneducated one a mile away.

Ownership can be a challenge as the burden is on that owner to pick the mechanic properly to work on that airplane and manage how maintenance is done. There are many excellent ones happy to give you their knowledge. Just do a little searching to find them.

My intent of writing the first sentence in this post was meant to point to the OP who is posting in the guest section without paying the $65 and doing much self education. Savvy helps some in certain ways, but then when you look at a used Savvy airplane it tends to have its fair share of deferred maintenance. Sometimes the airplane decides who is going to work on your airplane for you (by breaking away from your home mechanic). To me airplanes and large RV’s are fairly similar, its tough to own one if you don’t know a reasonable amount about how they work. COPA is an excellent resource full of many smart people, but you’ve got to pay the $65, do your self education, and spend time understanding rather than just searching for what you want to hear.

2 Likes

My notes from a member-side discussion are: Oil sump capacity for the IO-550N is 8qts; 5 usable at 16 degrees nose up and 4.5 usable at 10 degrees nose down. I don’t know your circumstances and operating technique. But, for reference, the most I see in my typical flying is 7-10 degrees nose up climb max.(initially) and 4-6 degrees max. nose down during approach to land, depending on the glide path I’m targeting.

I fly an SR 22 NA. The dipstick has been checked and the indicated oil level is accurate. I run 7 qts minimum before extended flights, and add oil when it gets down to 6, which takes a while. I only added 2 qts makeup oil on the last 25 hr oil run. And, for the last quart added, the oil level was only a hair below 6 qts cold prior to the last flight before the oil change. But, I won’t fly it under 6 qts.

The POH recommends 6 qts oil as a minimum in Section 8:

• CAUTION •
The engine should not be operated with less than six quarts of oil. Seven quarts (dipstick indication) is recommended for extended flights.

If your engine is venting oil excessively, there are multiple issues that should be checked for nonconformity and addressed.

Here is a link to an article written by Mike Busch that outlines in layman’s terms how to troubleshoot your issue. High Oil Consumption Of course, the Continental Maintenance Manual troubleshooting guide should always be consulted.

Good luck getting this resolved. As one example of risk, there was a CAPS pull in the UK resulting from bearing damage/ loss of engine power that the investigating body attributed to inadequate oil level in the sump. I’m not saying you’re headed for a CAPS pull. But, it’s risk you should consider when your SC is - allegedly - condoning your practice to run at a lower oil level than is recommended in the POH.

3 Likes

6 quarts is the minimum for dispatch.
In hot high density altitude days you should fill all the way to 8 to increase the surface area and volume of heat dissipation to prevent overheating.

Get an air oil separator by air Wolfe. You’ll clean the belly once every six months. Instead of every flight.

Burning that much oil tells me you have gunk building up on the rings or worse.

Take care of this ASAP. Please.

1 Like