Ovation oil level changes

[rickseeman]

So I checked the oil level in the Ovation and it said it was low. I couldn't explain that but I added oil. Next flight was an hour or so. After that flight but before the next flight I checked it and it was on 9. (I try to run 7.)  I made another 1 hour flight. Before the next flight it was still on 9. Yesterday another 1 hour flight and now it says 5. On yesterdays flight the oil pressure and temperature were exactly where you thought it should be. Somethings going on but I don't know what. I tried doing a search on here but got no hits. I thought I read a thread on here one time about a guy having similar problems. Maybe an oil relief valve or something? Thanks for your help. 

[GeeBee]

Capillary action in the dipstick tube. It cools faster than the engine. 

Make sure your dip stick is always oriented the same way

Pull the dipstick out of a cold engine for 30 minutes prior to checking the level, then drop it in and check the oil level. You'll get consistent readings.

I don't check oil levels during fuel stops, it won't be accurate. I check it before first flight of the day. I know my engine burns 3 ounces per hour (a quart every 11). Unless I see evidence of excessive oil leakage or consumption I take the overnight reading, subtract 3 oz per hour for my planned usage and make sure I will arrive with at least 5.75 quarts. 

[rickseeman]

I've seen the Skylane RG I used to fly "wick" oil up the dipstick but this read 2 qts low so I added 2 and next it showed 9. Now, after yesterdays flight it shows 5-1/2. I think it's still in there. I hate to fly it tomorrow showing 5-1/2 but I don't want to add any because I think theres 9 in there somewhere.

[Fly Boomer]

33 minutes ago, rickseeman said:

I hate to fly it tomorrow showing 5-1/2

It probably won't show 5-1/2 tomorrow before you fly.  After dripping down overnight, you will get a "better" reading.  

[rickseeman]

I'm just not getting that "warm and fuzzy" feeling with 5-1/2 quarts.

[GeeBee]

Take the stick out, and give it 30 minutes while you preflight. Then put the stick back in clean, and check it.

[A64Pilot]

There shouldn’t be any capillary action on a stick, and if there is just pulling it out and wiping the stick off and reinserting it will suffice.

Only time I’ve ever seen anything weird like that is on a Continental C-85, it has an oil tank, with full oil the oil filler neck is below the oil tank level, and the cap is air tight, so when the oil filler neck cools it will pull oil up into it and give you a high reading, but even then wiping the stick and immedately reinserting it will give you an accurate reading.

Trivia but as a Marine engine is designed for the oil tube to be used to suck oil out it, it’s below oil level and can do the same thing.

Lycomings will give a lower reading soon after shutdown, seems to take quite a long time for the oil to drain into the pan, which confused me, but I now think I know the reason why.

For whatever reason the oil filter does not have an anti-drain back valve, so over time the filter will drain into the pan, but it’s apparently not a quick process. 

What got me looking into that was reports that if you drained the oil over night and didn’t spin the filter off until the next day, you didn’t make much of a mess, meaning of course the filter emptied overnight.

So based on what I discovered there if you check soon after shutdown the filter is still full and level will read low, but next morning it’s not full and level will read higher. I don’t know if a Conti oil filter has an anti-drain back valve or not.

On edit, if want to leave the stick out for an extended period it’s not going to hurt anything, but I’d leave it in the tube but pulled halfway out, people have taken off having left the stick out, but with it sticking way up in the air that’s very unlikely.

[GeeBee]

There should not but there is. I got an R and it does it too. There is a half dozen threads about it on Beechtalk too.