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RV-9A Average Oil Consumption

Kevincav

I'm New Here
Apologies if this has been asked, I tried looking for it. I did a pre-buy for a beautiful RV-9A and most things seemed good. There has been concern about the oil consumption. It seems that it goes through a quart every 7-10 hours. Is this normal? I've talked to some people who were thrown off by it being so low. Obviously the seller / broker seem to think it's good. The engine has 740 hours on it with a new cylinder 4 years ago. This is an IO-320. This is the plane.
 
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My 9A will use up oil until about 5.25 quarts. Then it slows way down on consumption. So, when filling, I try to fill to about 5.5. I can run 10-15 hours on .25-.5 quarts.

That's anecdotal at best..

But if you were in a similar -320 engine and filled to 6 quarts - it would consume faster for sure.
 
I have an IO-320-E2D in my RV-9A. 820 hours as of now. I change the oil about every 35-45 hours, or every 4 months. Usually at around 30 hours I need to put in 1/2 quart to keep it at 6 quarts. I'm running Aeroshell W100 with Camguard. It doesn't really go through any oil. I send out my sample to Blackstone and they have basically said to keep doing what your are doing!
 
There seems to be a wide range of "normal" oil consumption in these engines. I'm no engine expert but from my pretty extensive investigations the consumption is a little high but still in the "good to go" range. But don't take my word for it -- the maximum oil consumption for the engine should be in the engine operation manual. If one of those isn't with the plane, it should be acquired and consulted.

It is a good idea to check for reasons why oil might be going where it shouldn't -- borescope the cylinders and look for pitting and check the condition of the valves, do a compression check, look for gunk out the tailpipe and on the belly, check for oil on the bottom plugs, and make sure there are no leaks. That will tell you if there is a specific problem.
 
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rv6n6r has it right.

compressions good? Oil on the belly? What about the spark plugs? If the lower plugs were oily, it's possible it could be an oil burner even if it has good compression. About the best way to tell other than that is to borescope through the spark plug holes.

Personally, I would be annoyed by an engine burning that much oil, but Lycoming will tell you not to worry about it until it gets into more like a quart every 2-3 hours.
 
Oil usage is all over the map - when I change oil and filter I put 7 quarts in, and my engine will dump most of 1/2 quart overboard within the first 2-3 hours. Then I'll need to add a quart at about 30 hours, and before I need to add another it's time for an oil change at 50 hours. I've got 750 hours on this engine and it has not been babied.
 
There seems to be a wide range of "normal" oil consumption in these engines. I'm no engine expert but from my pretty extensive investigations the consumption is a little high but still in the "good to go" range. But don't take my word for it -- the maximum oil consumption for the engine should be in the engine operation manual. If one of those isn't with the plane, it should be acquired and consulted.

It is a good idea to check for reasons why oil might be going where it shouldn't -- borescope the cylinders and look for pitting and check the condition of the valves, do a compression check, look for gunk out the tailpipe and on the belly, check for oil on the bottom plugs, and make sure there are no leaks. That will tell you if there is a specific problem.

He suspected that it might have oil consumption problems but didn't see anything on it.
 
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Oil consumption is HIGHLY variable, as you've seen in posts here.

I'll offer two examples here... My ~200hrs since new O-360 gets filled with 6 quarts plus the recommended amount of CamGuard at the time of oil and filter change. That results in just a hair under 6 quarts showing on the dipstick. I often fly at 75% power, often fly shorter flights of an hour or so rather than long multi-hour cruise flights. Typically somewhere around the 22-24 hour mark the oil is down to 5 quarts showing on the dipstick. I have not run it down lower than 5 quarts so can't say how long it would take to go through the next quart. For the price of a quart of oil I find it's not a big deal to just throw another quart in and fly until the next oil change.

By contrast, the Grumman Cheetah I used to fly with an O-320-E2G engine would get the same treatment at every oil change, targeting 6 quarts on the dipstick after the oil and filter were changed. It would be down to 5 quarts showing on the dipstick typically at the 8 hour point. That engine had 2700 hours on it when we removed it and was still running strong but was ready for overhaul. When I reviewed the logs for the engine that same 1 quart in 8 hours consumption rate had been documented since the owner started keeping records at about 1400 hours. The logs revealed a flat oil consumption rate across about 1300 hours and two decades of use. Clearly it wasn't an abnormal rate as it was very steady through the years and did not accelerate even as the engine went well past TBO.

Again, I'm tossing this info out here as a means to help you establish a perspective on what is "normal" oil consumption in a Lycoming.
 
Same

My 9A will use up oil until about 5.25 quarts. Then it slows way down on consumption. So, when filling, I try to fill to about 5.5. I can run 10-15 hours on .25-.5 quarts.

That's anecdotal at best..

But if you were in a similar -320 engine and filled to 6 quarts - it would consume faster for sure.

Same story with mine. right or wrong I took a side cutter and carefully made a new mark on the dipstick of where I think it seems most happy.
 
My IO360 likes 6 qts in the crankcase. I was adding a qt every 5-6 hours flying about 50-60 hrs a year. I have been flying much more in the past 6 months and I have noticed oil consumption has dropped to a qt every 10-12 hours!
 
Bonehead question regarding my upcoming first oil change in my IO-320...when you do an oil and filter change, how much oil do you put in?
 
One suggestion.
For Oil & Filter change, refill with 5 qts.
Run up the engine briefly, this fills the filter & sets the settled oil level in the sump.
After shut down, check oil level on dip stick, this confirms if the stick readings are accurate (you definitely know you put 5 qts in), re-mark it if the 5 qt. mark is wrong. Fill it to 6 and 7 qt. levels & re-mark these levels also.
Run the engine normally and if you find some oil is spit out over time, you will know how much to fill the engine for your next oil change.
Max on most Lycomings is 8 qts, but they will usually spit the excess out to a level they like to operate at.
 
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