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FYI R44 "Oil Consumption" - Discovered

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I've always thought my R44 Raven 2 is spitting out to much oil. Many, many people have told me it's normal.


I installed an oil air separator. This brought "consumption" and the puddles to what I considered normal with other ships, but, all of the underside is constantly covered in oil - to a level that I consider unusual. The actual oil levels are well, well, within the manufacturers spec for consumption with the oil sep in place. However, the puddles continue. Still told it's normal by several people.


During a 100hr this week - I was told the leak is, in fact, the mechanical fuel pump. Probably the diaphram inside failing - I've seen similar plenty (plenty) of times on old American cars. At Robinson today, they mention this is something they've been seeing a bit lately as well.


Just an FYI for those of you with "normal but not so normal oil consumption in an R44. (My ship is a Raven 2 with 900 hours on it and this has been happening for some time)

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Come on.


Oil. No fuel leaks sir. That would never be normal now would it.


I keep the oil at around 6.5qts. Anything more than 7 would just be blown all over the back of the helicopter regardless.


The pump is leaking, engine oil, not fuel. The mechanical pump is engine driven.


I'm confused..........was it leaking fuel or oil? If it was fuel, you should have seen blue stains on everything versus the yellowish oil stain.


BTW, what did you keep the oil level at? The full 9 qts?

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Ok, but you said: "During a 100hr this week - I was told the leak is, in fact, the mechanical fuel pump. Probably the diaphram inside failing - I've seen similar plenty (plenty) of times on old American cars."


The fuel pump CANNOT leak oil--it doesn't have any oil in it. If the diaphram was leaking, it would be leaking fuel, not oil. So maybe the seal where it bolts on to the back of the engine is leaking? But if the FUEL PUMP was leaking, you'd see blue stains because it's leaking fuel. This does not explain the "puddles of oil" you described.


Good job keep it at 7 qts. So many people refuse to keep it below the full 9 qts and lose 2-3 quarts a flight. That engine will run on 2 qts per Lycoming, but I wouldn't want to try it.




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Oil can escape through the seal into the fuel pump. It will then leak from the Fuel Pump Diaphram leak check drain hole, through the drain tube and out the bottom of the engine compartment. It is not leaking from the seal to the engine, but rather from the pump itself. The fuel pump CAN leak oil. This is due to a leaky oil seal and not the diaphram. This does explain the "puddle of oil".


Bad Job to keep it below 7 qts. With an air/oil seperator correcly installed it should be able to maintain 7-9 qts with only minimal blow by. The minimum required is 7 at the very least as this is an operating limitation of the engine.


Lycoming does not say the engine will run on 2 qts. This is often mis-stated. What Lycoming says is that in the event of a catistrophic lose of oil in flight, if you land and can drain at least 2 qts. from the sump, then you have likely not caused damage to your engine. IF you try to operate the engine on 2 qts., it will be a very short, disastrous flight


Just my informed 2 cents worth.


Private, A&P/IA, 20 + years working on Robinson R22 and R44's.

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How can it leak "puddles" or "pools" of oil? That arm is not pressure lubricated, it's just picking up oil sprayed on the camshaft, right? I can't imagine it having more than a teaspoon to leak out of the vent hose if the engine is static. He has other leaks if there are pools/puddles--something than contains oil when the engine is static.


I disagree on the oil level though. Lycoming does not recommend keeping their engines at max capacity unless you are embarking on a LONG flight. I don't know about the IO-540 but the minimum for the O-540-F1B5 was not 7 qts, it was lower (5 qts per the POH I thought). Lycoming recommends having the engine midway between maximum and minimum for normal flights if you encounter this problem. This was in the reprints of their service letters.


If his engine tosses anything over 7 qts out the breather, why put 9 in it? That seperator mounts on the breather right? So the the engine is still throwing that extra oil out and you're just seperating it and dumping it back in the sump, right?


And per Lycoming school, that engine WILL run at 2 quarts in the sump........They state you should never takeoff at this level in the service letters, but it will run. If that engine sits straight and level it should run for quite a while. When it drops below that or that pump cavitates due to banks & turns, YES disaster is pending.


Not trying to start a war here or anything, just trying to figure out where else this guy's helicopter is losing oil.


First thing we always did in the first few hundred hours was replace all those cork seals. We'd be in there to re-time the mags and ream the valves anyway, so'd put replace all of them with the orange synthetic seals. Cut down on a lot of the little drips. Check your oil filler tube too, those plastic ones always seemed to back off because they didn't expanding & contract with the engine.

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Actually talked to the factory about it and it's something they've seen before. I am not "informed" and am not an A&P but it is happening :) and is something worth watching for. The A&P that has serviced my ship in the past noted it during a 100hr as its been a complaint of mine.


For the oil air/sep, can you let me know what can actually be done wrong with it ? I typically maintain the ship at 6-6.5 qts, Robinson seems to unofficially agree this is a typical capacity with no oil being blow out. 7 quarts, even 8, I had "heard from other pilots" is possible with the Airwolf air/oil sep without abnormal blow by.

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I've never played with air/oil seps.....sorry, don't know anything about them. With stuff like that, I used to say , "If they were that great, they'd put them on at the factory." However, there are a lot of field improvements out there that the factory (Lyc. or RHC) don't put on.


Those silicone seals are the best example. RHC didn't used to offer an oil filter for the R22 until enough people complained or bought the remote one (then they stole the design from B&C). The floor xmit switch was a famous one for as told by Tim Tucker. So, who knows, they might be worth, might not. Maybe the factory will put them on one day.


Good luck!

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I totally agree, not try to start anything. My notes from Lycoming School say something different about the 2 qts rule, but it is neither here nor there as I don't know anyone willing to try it.


I have replaced several engine mounted fuel pumps for this exact reason. It can cause the problem stated and should be replaced. An easy check is to look at the fuel pump and sniffle valve drain tube. If it has oil in it, the pump is a problem. Have it changed. If your ship is less than 2 years old its under warranty.


The M20 Air/oil seperator works well if installed right. The problems are the tight space, and limited choices for oil return to the engine. If the return is not a constant downhill slope, then the tube will fill with oil and any benefit will be lost until tube is cleared again. With it properly installed you should be able to maintain up to full capacity with minimal blow by. You may always get a few drips under the breather when you park, but your belly should stay much cleaner. I have installed one of these on a R44 Astro and it works great. I havent tried a Raven II yet so I have no data.


The R44 engines, O-540-F1B5 and IO-450-AE1A5, both have dipsticks marked at 7 and 9 qts. This is a Lycoming requirement, not RHC. It has to do with lubrication, cooling, engine installation, etc. Most of the 540's I have seen installed on a fixed wing have 9-11 or 10-12 qt. sumps. The engine as installed in a R44 cannot be serviced this high due to way it is installed. The angle that the engine sits at during normal flight can vary greatly depending on C.G., loading, etc. This is also a reason you get so much blow by. RHC has on later helicopters reduced the diameter of the breater outlet and breather tube to try to minimize this problem. RHC has talked about getting Lycoming to reduce the oil requirements to 6 qts. but have not succeeded. My only point about capacity was that this is a requirement. Most people know the unofficial line from RHC is to run them a little below 7, but IF you are ramp checked, the answer should be 7 minimum.


I don't know what type of oil your using either, but I would tend to stick with the Single Grades instead of Multi Grade if you can.

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