As on any plane I check the oil before each flight and make sure it is in range, when it gets near the bottom end of the range add enough to bring it near the top. 

The question is how many hour are you expected to go between having to add a quart?

In cars I often never have to between oil changes, but what do folks see in real-world use of the car engine in airplane use?

I am sure how much you push it will influence it. Has anyone kept track or noticed? If I go on a long cross country, how much should I pack?



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Our Rotax 912 UL uses 1/4 quart every 30 to 40 hrs.  We can't add a full qt when level at bottom of range or it will overfill.  We change oil just before going to OSH and it takes about 1/4 qt round trip of about 40 hrs. Carrying 1 qt has lasted 2 yrs, but now only about 1/4 qt left.  Have about 240 hrs on plane. Rotax needs oil change every 50 hrs if using 100LL, but only every 100 hrs if using premium mogas.  Get the mogas at Coop in Snohomish, using gas cans.  On cross countries have to use 100LL.

I'd like to share our oil consumption numbers but need to first fix a small leak.

I just got back from a 13.5 hour XC.  In that time I added 3 quarts of oil.  As far as I can tell, it's neither leaking oil nor burning it.  I do see some spray on the ground come out of the exhaust when I start up.

My cruise rpm's are generally between 4650 to 4920, with most flying being at 4800 rpms.  My altitudes ranged from 3500 ft to 11,000 feet, with most cruising done around 6,000 feet.

Engine seems to be running good, and none of the indicated temperatures or pressures are out of line.  I'm running 0W-20, which is extremely thin.  Like water.  I may try a slightly heavier weight of oil.

During this same trip my fuel burn was 3.96 gph.  

- Pat

A quart every 4.5 hrs. seems excessive to me. Maybe Jan will chime in......

Thanks Patrick. I have some oil showing up in strange places where air vents and I think there may be a oil leak misting some oil inside the cowling, but I have not been able to find the source yet.

Patrick what is your empty weight on your 650?

We have a small leak which appears to be from the chain tension adjuster cover.  Could not find any oil radiation from another source.  Took it off once, cleaned up the mating surfaces and applied sealant.  Still leaks so we need to revisit.  Although there's little crankcase pressure, perhaps one more fastener on the outboard side of cover would help?

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I've noticed a drop there as well, so will have to take another look...

On my previous engine (not a Viking) I successfully dealt with a leaky mating surface by using a product called "Honda Bond".  It was referred to me by a guy who used to run a Formula 1 team.  It's good stuff, and available at local Honda dealerships.

Otherwise, my Viking engine is running good.  It's given me new confidence in this airplane.

- Pat

The same stuff but available at the auto store is "The Right Stuff"  it is far better than a silicone based sealer.

Don't get the gray one, it is different.  This 1/2 caulking tube insert is best.  It will stay reusable later.   


Could it be coming from your crankcase vent?

That's possible.  On a recent trip I climbed to around 11k feet to get around some weather, and flew generally higher than usual for extended periods.  Oil consumption was less (I was watching it) on the way back home, when I flew lower and didn't climb hard so much.

- Pat

Some oil usage is normal. Leaks will add a lot to the usage.

Don’t change the viscosity of the oil from what is written on the oil cap. The engine use the thinner oil for the variable valve timing and lift solenoids.

Oil leaks can best be found by removing the propeller and cleaning suspected areas with non chlorinated brake cleaner.

Once the leak has been remedied, Use a 1” brush and add a light coat of ACF corrosion inhibitors to the entire engine to keep it nice and new looking. Only add a tiny amount to the brush. Do this to the plastic and metal parts / bolts, etc.

Verify engine compression during preflight with ignition off. (If not off, Engine can start)
There should be 4 even pulls of compression while flipping the propeller through. Do this to verify valve adjustment is good and to see if 100LL fuel is getting into the rings (lead).

The proper lead scavenger for the engine is Marvel Mystery oil. Not any additive supposedly made for this purpose. Add the oil to the fuel as described on the bottle. It will lubricate the combustion chamber just enough to prevent the lead sticking to components.


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