Hey Seneca owners,

I'm a new proud owner of a 1977 Seneca II, and am trying to determine the right oil levels for my engines. We all know they have 8 qt sumps, and we all know that if you fill to 8 qts, you blow oil out the breather, but I am trying to figure out where my engines really want to be oil-wise. I'm trying to determine if I have an oil consumption problem, or just don't quite understand the TSIO-360's yet.

Here's what I know. I had the oil filled till the levels read 7 qts on both dipsticks. On May 17th, I flew for 0.9 hours. The next time I went out (a week later, on May 25) both engines were at 6 qts. (1 qt per hour consumed wouldn't be great.) On May 25, I flew 1.6 hours. On May 26th (20 hours later) I checked the oil levels before our flight and found the left engine a little less than 5.5, and the right, just a little over 5. At this point I suspected an oil consumption problem. I flew 0.9 again on the airplane. A few days later (well over the 20 hours from the prior readings), we read the left engine at 5.5 and the right at just under 6 qts, significantly higher than the last readings.

So far, what I think this tells me is three things:
1) The engines are gonna throw anything over 6 qts overboard.
2) The engines need a few days for all of the oil to drain back into the sump; 20 hours is not enough time.
3) Once below 6qts, my engines are not burning an obscene amount of oil.

Here's the wrinkle. I asked my mechanic to do a reset. I asked him to do an oil change. He drained, replaced the filters, and added exactly 6 qts per side, per my instructions. Then ran the engines up to check for leaks. Three days later, I go to pick up the airplane out of maintenance, and find 6 qts in the left engine, and only 4 in the right. I checked both dipsticks side by side; they appear to be marked the same. I am wondering if the dihedral, which affects the tilt of each engine is a factor here.

Does anyone have anything to share in light of this information? Can you guys set me on the right track? I've only completed flight #6 on this airplane, so am definitely new to this and still trying to figure this all out.

Thanks in advance,
Dan