Piper Cherokee oil usage??

jmarine225

jmarine225

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Jmarine225
Haven’t made it in here in a bit as all has been good. I have a 1969 Cherokee 140and some strange things have been occurring. For one, it seems to be using more oil than usual. Last add was 1 quart per 5.8 hours. It may actually be lower than that now. Last oil change was in February and probably 30 hours on it since then. I know it’s due for a change now. We checked and can’t find oil anywhere on the fuselage. Looks like some is blowing out the breather. When I purchased it I was told it has chrome cylinders so it uses more oil than usual, roughly 1 quart for every 5 hours.

Along with this, it seems the oil temp is low during flight and climb. It is a it cooler out now so maybe that’s the reason, but doesn’t hit 180 pm the gauge. Oil pressure is good. Also get the occasional slight fouling on run up which clears quite easily. Had new plugs installed last year as old ones were out of spec. Any suggestions here or is all good? I just don’t want to keep running it if I may be causing more damage. It also sat ALOT this year and only recently began putting some decent hours on it.
 
jmarine225 said:
Haven’t made it in here in a bit as all has been good. I have a 1969 Cherokee 140and some strange things have been occurring. For one, it seems to be using more oil than usual. Last add was 1 quart per 5.8 hours. It may actually be lower than that now. Last oil change was in February and probably 30 hours on it since then. I know it’s due for a change now. We checked and can’t find oil anywhere on the fuselage. Looks like some is blowing out the breather. When I purchased it I was told it has chrome cylinders so it uses more oil than usual, roughly 1 quart for every 5 hours.

Along with this, it seems the oil temp is low during flight and climb. It is a it cooler out now so maybe that’s the reason, but doesn’t hit 180 pm the gauge. Oil pressure is good. Also get the occasional slight fouling on run up which clears quite easily. Had new plugs installed last year as old ones were out of spec. Any suggestions here or is all good? I just don’t want to keep running it if I may be causing more damage. It also sat ALOT this year and only recently began putting some decent hours on it.
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I say it is all good.

My buddy has the same plane and watches his oil consumption very closely. I helped him and his AP/IA mechanic do his annual and motor leak down recently. His leakdown numbers were all above 70 and his oil usage is about 1 qt per 4-5 hours, closer to 4 hrs per qt. His long time mechanic said not to worry about it. His motor has been flying like this for the past 3 years that I know about. His motor is a mid time motor approx 1000 hours.
 
1 qt every 5 hours is well within spec. You don’t say your actual oil temp but if your above 170 it should be fine. What color is your oil after about 5 hours of runtime. If it’s deep black your getting blow by. How many hours on the motor?
 
You might be surprised to learn the spec for oil usage in the 140. I don’t remember the exact number (and I’m going to violate an internet rule by not posting what I remember it to be), but I do know the permissible usage rate is considerably higher than what you are seeing

Enjoy the 140
 
How much oil are you running? Is there a lot of oil staining on the belly? Usually running at max fill ends up pushing oil out the breather. I have a 180 and fill to six quarts and re-fill at 5. Also, how does the engine itself look? I had a very tiny leak in one of the valve covers that was gradually getting worse and was spitting out a pretty large amount of oil. It was nearly impossible to find as the hurricane under the cowling blew it all over the engine compartment and I had to clean the entire engine to locate the source of the leak. New gasket and it's all good now.
 
Jeff767 said:
1 qt every 5 hours is well within spec. You don’t say your actual oil temp but if your above 170 it should be fine. What color is your oil after about 5 hours of runtime. If it’s deep black your getting blow by. How many hours on the motor?
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Well the gauge is pretty simple with the 180 marker and it’s a bit below that so it’s hard to tell the actual temp but well within the green. Oil is still a good color, no issues with that. Approx 500 hours on the rebuilt engine now.
 
jmarine225 said:
Haven’t made it in here in a bit as all has been good. I have a 1969 Cherokee 140and some strange things have been occurring. For one, it seems to be using more oil than usual. Last add was 1 quart per 5.8 hours. It may actually be lower than that now. Last oil change was in February and probably 30 hours on it since then. I know it’s due for a change now. We checked and can’t find oil anywhere on the fuselage. Looks like some is blowing out the breather. When I purchased it I was told it has chrome cylinders so it uses more oil than usual, roughly 1 quart for every 5 hours.

Along with this, it seems the oil temp is low during flight and climb. It is a it cooler out now so maybe that’s the reason, but doesn’t hit 180 pm the gauge. Oil pressure is good. Also get the occasional slight fouling on run up which clears quite easily. Had new plugs installed last year as old ones were out of spec. Any suggestions here or is all good? I just don’t want to keep running it if I may be causing more damage. It also sat ALOT this year and only recently began putting some decent hours on it.
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How much oil do you usually keep in it? I assume this an an O320, which I have been flying one well over 10 years. Mine is 52 years old and has had one cylinder replaced since it was new. I usually put 7 quarts in at oil change and it seems to stay around 6.5 for a while then at about 15 hours it seems to start burning a quart every 5 or so similar to yours. Its been doing this for about a decade. I usually keep 5-6 quarts on the dipstick and on really hot days add more. I usually change the oil around 30-35 hours. This thing has been on a steady diet of 205w-50 X-Country for at least 20 years.

I don't think these engines have any sort of valve seals so it seems to me it can suck oil into the combustion chambers through the valve guides, which is normal for these engines.
 
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Hang 4 said:
How much oil are you running? Is there a lot of oil staining on the belly? Usually running at max fill ends up pushing oil out the breather. I have a 180 and fill to six quarts and re-fill at 5. Also, how does the engine itself look? I had a very tiny leak in one of the valve covers that was gradually getting worse and was spitting out a pretty large amount of oil. It was nearly impossible to find as the hurricane under the cowling blew it all over the engine compartment and I had to clean the entire engine to locate the source of the leak. New gasket and it's all good now.
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I like to keep it at 6. Everytime I do it goes back down to 5. There’s oil on the bottom of the cowling under the breather tube but not an excessive amount under the belly.
 
bnt83 said:
How much oil do you usually keep in it? I assume this an an O320, which I have been flying one well over 10 years. Mine is 52 years old and has had one cylinder replaced since it was new. I usually put 7 quarts in at oil change and it seems to stay around 6.5 for a while then at about 15 hours it seems to start burning a quart every 5 or so similar to yours. Its been doing this for about a decade. I usually keep 5-6 quarts on the dipstick and on really hot days add more.

I don't think these engines have any sort of valve seals so it seems to me it can suck oil into the combustion chambers through the valve guides, which is normal for these engines.
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Well it’s time for an oil change which may be the case as my last one was February and haven’t flown it a lot this year. Maybe 30 hours since the change.
 
You may find that oil usage increases as the oil gets older. I first noticed this on an old Plymouth I owned. After an oil & filter change the engine went 1200 miles and used 1 quart. The second quart only lasted 800 miles. So I started changing oil after the second quart on that car. I think that is still a good practice, but you should keep track and decide for yourself.

Oil degrades the longer it stays in the engine. That's why you change it. It makes sense that fresh oil is less degraded than older oil and the engine would use less of it. But your engine may or may not behave that way.

Hope this helps.
 
jmarine225 said:
I like to keep it at 6. Everytime I do it goes back down to 5. There’s oil on the bottom of the cowling under the breather tube but not an excessive amount under the belly.
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Do you mean you fill it to 6, and then it very quickly goes down to 5? If so, that's normal and what others are talking about here. Most engines seem to do this - you fill it up to the rated capacity, and it quickly spits some overboard until it finds its preferred level. Try just running it at 5, see if you continue to burn oil, or if it levels off. Maybe only put a quart in once it gets down to 4.5. Or put a half quart in at that point. Minimum oil level in that engine is probably 2 qts.
 
William Pete Hodges said:
You may find that oil usage increases as the oil gets older. I first noticed this on an old Plymouth I owned. After an oil & filter change the engine went 1200 miles and used 1 quart. The second quart only lasted 800 miles. So I started changing oil after the second quart on that car. I think that is still a good practice, but you should keep track and decide for yourself.

Oil degrades the longer it stays in the engine. That's why you change it. It makes sense that fresh oil is less degraded than older oil and the engine would use less of it. But your engine may or may not behave that way.

Hope this helps.
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My motor and my buddy's motor behave in this way. They use less oil right after an oil change and as the oil get's older it is burnt faster. Our mechanics have confirmed this theory.
 
RussR said:
Do you mean you fill it to 6, and then it very quickly goes down to 5? If so, that's normal and what others are talking about here. Most engines seem to do this - you fill it up to the rated capacity, and it quickly spits some overboard until it finds its preferred level. ...
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Max fill for the O-320 is 8 quarts. Most O-320s do not blow out a quart if only filled to 6 quarts.
For my Warrior II, O-320-D3G, I fill it with 6 quarts at the oil and filter change. I add a quart when it hits 5 quarts. It consumes about 1 quart/12 hours. It has nitride cylinders.
 
Gary Ward said:
My motor and my buddy's motor behave in this way. They use less oil right after an oil change and as the oil get's older it is burnt faster. Our mechanics have confirmed this theory.
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If you are changing your oil every 50 hours, there is not enough time/use to lower the viscosity enough to cause more oil consumption. Even with a filter change the engine retains 1/2 to 1 quart of oil. When you fill it with six, it actually has 6-1/2 to 7 quarts. That first quart of consumption seems to take longer because it's actually 1-1/2 to 2 quarts.
 
Domenick said:
If you are changing your oil every 50 hours, there is not enough time/use to lower the viscosity enough to cause more oil consumption. Even with a filter change the engine retains 1/2 to 1 quart of oil. When you fill it with six, it actually has 6-1/2 to 7 quarts. That first quart of consumption seems to take longer because it's actually 1-1/2 to 2 quarts.
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I am going to disagree with that. Air cooled engines are particularly hard on oil because many of the surfaces in the engine are hotter than they are in water cooled engines. I change my aircraft engine oil about every 20-25 hours. The filters are good for 60 hours so I let my AI change the filter at the annual. It usually works out to 50-60 hours per year and my AI is ok with this. My Mooney doesn't have a filter, only a screen, and the factory recommends 25 hours if memory serves.

Most of the dirt in oil remains in suspension and is not caught by the filter. So the longer you run the oil the more it acts like lapping compound inside your engine. The only way to get rid of it is to drain the oil, a big benefit to the longevity of the engine. Changing the oil filter more often? Not as much benefit as changing the oil IMHO.
 
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Domenick said:
When you fill it with six, it actually has 6-1/2 to 7 quarts. That first quart of consumption seems to take longer because it's actually 1-1/2 to 2 quarts.
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How do you figure? How does the engine have more oil than what you fill it with?

If you fill it with six, you actually have closer to five or five and a half, once the filter fills up.
 
RyanB said:
How do you figure? How does the engine have more oil than what you fill it with?

If you fill it with six, you actually have closer to five or five and a half, once the filter fills up.
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LOL I was just going to say "wut?"
 
RyanB said:
How do you figure? How does the engine have more oil than what you fill it with?
If you fill it with six, you actually have closer to five or five and a half, once the filter fills up.
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I'm willing to be convinced I am wrong, but ...

The engine retains some oil in surface films, galleries, nooks, and crannies. How much oil do you think it retains? It's more than zero.
 
I'll share..
5 1/2 seems to be just about max on my O-320. It'll spit it out above that.
I run it between 4 1/2 and 5 religiously. So far getting about 9-10hrs/qt.
This is at 650hrs with new factory Lycoming cyl's at install.
 
My AP always said to fly just above the min level otherwise you lose more. Kind of easy for him to say while his feet are on the ground.
 
Joe Pilot said:
My AP always said to fly just above the min level otherwise you lose more. Kind of easy for him to say while his feet are on the ground.
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The minimum level in an O-320 is two quarts. Not gonna fly my plane with just over 2 quarts.
 
This is a reasonably normal oil consumption, especially with a channel chrome cylinder. If you are getting mild oil fouling, you are likely consuming oil via combustion from blowby, and not out the crankcase breather. When the fouling gets serious, it may be time to deal with the loss of oil control in the offending cylinder(s). I've flown an O-320-E2G for 35 years. I put in 7 quarts, then add a quart when it gets to 6. It will discharge the first quart pretty quickly if you go full capacity (8 qt). When I had one or two chrome cylinders, 6 hr per quart was pretty good. With new nitrided steel, it's more like 15 hours per quart broken in. Whenever I got less then 6 hours per quart and frequent wet, fouled plugs, I could usually find the offending cylinder with bad oil control rings.
 
chemgeek said:
This is a reasonably normal oil consumption, especially with a channel chrome cylinder. If you are getting mild oil fouling, you are likely consuming oil via combustion from blowby, and not out the crankcase breather. When the fouling gets serious, it may be time to deal with the loss of oil control in the offending cylinder(s). I've flown an O-320-E2G for 35 years. I put in 7 quarts, then add a quart when it gets to 6. It will discharge the first quart pretty quickly if you go full capacity (8 qt). When I had one or two chrome cylinders, 6 hr per quart was pretty good. With new nitrided steel, it's more like 15 hours per quart broken in. Whenever I got less then 6 hours per quart and frequent wet, fouled plugs, I could usually find the offending cylinder with bad oil control rings.
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Well I had the oil changed and my A&P took a look at it. He also did a compression check with the following results: 68, 67, 72, 76. He filled it with 7 quarts of oil, ran it fine and no leaks. So far I've put approximately 5 hours on the engine and am down to 4 quarts now. No idea where this oil is going. He says it is running fine, no issues but I feel as though I'm using alot of oil as compared to the past. Engine has approximately 485 SMOH. Any suggestions?
 
Hang 4 said:
Run it at 6 and see how long it takes to get to 5.
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After the oil change I ran it down to 6. Put 1.9 on the Hobbs and was a bit above 5. No obvious leaks anywhere.
 
What do the bottom plugs look like?

If it’s not going all over the belly and there’s no visible leaks, than it must be getting burned. Seems like you’ve got enough data by now to determine a trend.
 
RyanB said:
What do the bottom plugs look like?

If it’s not going all over the belly and there’s no visible leaks, than it must getting burned. Seems like you’ve got enough data by now to determine a trend.
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plugs were clean when he pulled them for the compression check. This A&P is very experienced with cherokees and says its fine. Seems to be using alot to me. What should I do next? Investigate further or keep running it?
 
My first thought is to ask where those two cylinders in the 60’s are leaking. Rings? Although if the plugs are clean, than blow-by can’t be that high.
jmarine225 said:
After the oil change I ran it down to 6. Put 1.9 on the Hobbs and was a bit above 5. No obvious leaks anywhere.
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So 1.9 Hobbs is roughly 1.7 on the tach and you lost about a quart.
jmarine225 said:
He filled it with 7 quarts of oil, ran it fine and no leaks. So far I've put approximately 5 hours on the engine and am down to 4 quarts now.
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In 5 hours you’re down 3 quarts. So, 5/3 = 1.6

Based on this, it seems you average 1.65hrs per quart. To me, that’s a pretty high consumption rate and if it was my engine, I’d want to know where the oil is going, because it shouldn’t be burning that much.
 
That does seem like a lot. Is the engine clean? Nose seal is one area that can be prone to leaking, valve covers is another. Have you tried running something through the breather to make sure it's clear? A blockage can create internal pressure that can blow out oil. If the engine is not immaculately clean, you might try giving it a thorough clean and see if anything is leaking. I had a very minor leak in a valve cover gasket that was impossible to see, but fixing it moved me from about 2qts/HR to 5. Only way I figured it out was a drip of oil on a spark plug wire. That area gets so much wind from the prop, it just blew all through the engine compartment and it just looked kind of "normally dirty" .
 
Are you sure the dip stick is marked correctly?
 
"Lycoming uses the following formula to determine maximum oil consumption: (. 006 x BHP x 4 )/ 7.4 = maximum quart/hour consumption. This means that, for a typical 180-horsepower engine, using one-half quart per hour is acceptable to the manufacturer." Quoted from an AOPA article 5 yrs ago. But I've seen the formula published other places.

Frankly, if my Lycoming was using 1 quart every 2 hours, I'd be concerned. I once ferried a 172 that used exactly that. 1 every 2. It turned out to have broken rings in 2 cylinders.
 
Htaylor said:
"Lycoming uses the following formula to determine maximum oil consumption: (. 006 x BHP x 4 )/ 7.4 = maximum quart/hour consumption. This means that, for a typical 180-horsepower engine, using one-half quart per hour is acceptable to the manufacturer." Quoted from an AOPA article 5 yrs ago. But I've seen the formula published other places.

Frankly, if my Lycoming was using 1 quart every 2 hours, I'd be concerned. I once ferried a 172 that used exactly that. 1 every 2. It turned out to have broken rings in 2 cylinders.
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Yeah I agree it’s concerning. Any way I would know of the rings were bad? What does it involve and of course the cost?
 
jmarine225 said:
Yeah I agree it’s concerning. Any way I would know of the rings were bad? What does it involve and of course the cost?
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Pull the cylinders and take a look. its pretty easy. Pull the valve covers undo the cylinder head bolts, pull head off, look at pistons.
 
Before you pull cylinders:
--Check the breather tube and nose seal as suggested by Hang4.
--Find out where the leak down is in all the cylinders as suggested by RyanB. At pressure, listen at the exhaust pipe (exhaust valve leak) and oil fill tube (rings leak). Your A&P should know this and have done it when he did the compression test.
--Pull the oil sump screen and look for broken ring bits. (You may already have done this).
--Borescope each cylinder. Broken rings may leave cylinder wall evidence. Piston skirt scuffing is common and okay, and your A&P should know the difference.
--Add fluorescent dye to the oil, fly for an hour or more, and look for leaks. Your A&P should know how to do this. At 1.65hrs/quart you may not even need to clean the engine compartment.

My personal guess is you have a leak. Burning that much oil and not having spark plug evidence seems highly unlikely, though weirder things have happened. What kind of spark plugs are you running? Brand and model number? I suppose a hot, extended nose plug might not show burning oil.
 
Before you start ripping cylinders off looking for a problem I’d suggest taking the airplane to a reputable engine shop for assessment. Listen to what they have to say and formulate a repair plan based on their diagnosis. Some things can’t be inspected without exploratory surgery but i personally think cylinder removal is excessive at this point in time.
 
Has anyone ever looked at the minimum oil level? It's shockingly low. On an io-540 I thought it was something like 3 quarts and max is 12. Anything above 9 gets spit out right fast dead quick in a hurry.

I've been trying to determine the proper level on the more than mid time o-360 I just got to determine if it's on the belly or possibly being consumed. So thanks hang4 for what you do. Was filling to 7 and was losing a bit.
 
Racerx said:
Has anyone ever looked at the minimum oil level?
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Racerx said:
I've been trying to determine the proper level on the more than mid time o-360 I just got to determine if it's on the belly or possibly being consumed.
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Yeah it’s only like 2qts in an O360. I wouldn’t ever intentionally run it that low, but it’s nice to know it can safely operate on such little oil.
 
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