A&P says Continental O-200D supposed to leak. Is that correct?

kicktireslightfires

kicktireslightfires

Pre-takeoff checklist
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kicktireslightfires
My A&P is trying to convince me it's normal for my O-200D to have "minor leaks" and that they are normal. I'm trying to explain to him that I need to trust my life to this engine. Has Continental ever come out and said this is normal? If the manufacturer of the engine says that minor fluid leaks are normal, I'll believe it. Otherwise, should I, really?

Here are a couple photos of what my A&P is saying is normal. Best photos I could take without removing the lower cowling. I'll do so and get some better photos if you guys would like to see. But it appears that this gasket is leaking and has been leaking all over the exhaust muffler below it for quite some time.

I also see multiple other places looking underneath with a flashlight that have fluid running down them. The airplane runs perfectly fine and the T&Ps are all green. But I don't feel very good about seeing shiny fluid dripping along stuff in the engine bay. Am I overreacting?

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I have seen a lot of small Continentals. I don't think I have ever seen a completely dry small Continental although maybe that unicorn exists. Having said that some of it depends on where the oil is coming from. Probably the most common is pushrod tube leaks.
 
Yeah I would agree, it’s so common that it’s generally regarded as being ‘normal’. In these engines, a little bit of seepage can look like a lot, as the air blowing around it can do some interesting things. Just keep an eye on it, but it’s usually not cause for alarm.
 
I don't think it was designed to leak but, as noted by the others, it's kinda par for the course. To clarify I think "seepage" is to be expected but leaks should be corrected.
 
Airplane engines have more of a tendency to “sweat” than late model cars but I would be fixing any leak that is more excessive than that. It can be very time consuming keeping an engine leak free but it is worth it.
 
I doubt CAT(continental) will ever come out and say engine leaks are fine, but that doesn't make nuisance leaks an unairworthiness item. I think many of these are because the engines are so old that many of the mating surfaces are not flat enough have been damaged by gasket scraping tools that the gaskets/orings/silk thread cannot do the job any more.
Still, I do not ignore fluids which should be inside the engine, found outside the engine. I would do your best to identify and correct all leaks.
How much is on the hangar floor after a day or week?
 
Think of it as corrosion protection.

I’m not commenting on your picture, because it’s impossible to really tell by that, but minor leaks are definitely the norm, I’d trust my a&p. Should be cheap or even free to have another take a quick look and give a second opinion.
 
DFH65 said:
I have seen a lot of small Continentals. I don't think I have ever seen a completely dry small Continental although maybe that unicorn exists. Having said that some of it depends on where the oil is coming from. Probably the most common is pushrod tube leaks.
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My O200 allegedly has the real gaskets pushrod tube seals and does not leak.
 
kicktireslightfires said:
Has Continental ever come out and said this is normal? If the manufacturer of the engine says that minor fluid leaks are normal, I'll believe it.
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TCM has documented that the acceptable oil consumption of an O-200 is .5 quarts per 3 hours. So you can look at it that TCM thinks the loss of that amount of oil is not detrimental to the operation of the engine.
kicktireslightfires said:
But I don't feel very good about seeing shiny fluid dripping along stuff in the engine bay.
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Can't really tell anything from the pics, but as mentioned some engines leak, some don't, with some more common than others. The small A and C engines falling under the latter. Can oil leaks be stopped. Sure. But the cost and success tends to be subjective to the particular engine. It can range from a simple regular torque check of the valve covers, to a seal replacement, or in some cases require a new part. Perhaps at your next annual have the engine cleaned well and start to monitor the leaks on a regular basis. If they are considered "excessive" to you then you can look at correcting them. However in my experience most owners tend to keep an eye on the oil use and fly with it until either they tire of cleaning the belly or the oil use get into their uncomfortable range.
 
Just learning, so please be gentle, but is this a Continental thing? Or is this common to all piston engine aircraft regardless of manufacturer (Lycoming, Rotax, etc.)?
 
gearFX said:
but is this a Continental thing?
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It's more an engine thing. Any engine can be susceptible to regular leaks regardless if piston, turbine, or jet. Some engine OEMs publish static/dynamic leak rates. But as mentioned some models tend to regularly leak more than others similar to these particular small TCM models. Plus the age of the engine comes into play as TCM no longer produces most of the smaller models.
 
Air cooled Porsche has the same issue, particularly older ones. Same horizontally opposed, oil cooled engine architecture. The split case is under tremendous mechanical force. The pistons working hard to tear it apart and a bunch of bolts and seals trying to hold it together and keep the oil inside. Over time some is going to ooze out. Add the hurricane in the engine compartment and it adds up to a mess.
To the OP - what is your oil consumption? The "oozing" rarely is enough to make a measurable difference in consumption, but if it's high, then it needs looking at.
 
CA182R said:
My o-470 has a wet-looking pushrod. I wondered if that's common or a problem..
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Assuming you mean the seal around the tube is wet? If so, yes it’s common.
 
I could build a leak-free Continental. Many overhaulers do, but as these things age they suffer the same issues as any car, including deteriorating seals and gaskets. We expect too much from mechanical things.

The little Continentals have some weak spots. The case seam is the least of them, and following the instructions in the overhaul manual will prevent them, but some guys use what they feel are "better sealants" or something and they end up leaking, or with engine damage from broken-off pieces of sealant inside the engine. Those case bolts are more than strong enough to keep the case from fretting. There are leak paths around the through-bolts that can be prevented with a tiny bit of sealant around the bolts at the case flange during case assembly. The pushrod tubes are "permanently" installed in the cylinder heads with a special swaging tool, and they don't leak until someone takes a cylinder off and carries it by those tubes, which works them loose and they'll start leaking. The seal kits mentioned by GeorgeC are the permanent answer to that, but I have sealed them up by removing the rocker cover and completely deoiling the rocker box and by rinsing the tube/head joint with brake cleaner and blowing it out with compressed air to get that interface clean and dry, and using a small bit of Loctite 290 (the wicking stuff) on them. Just a bit; you don't want hardened loctite escaping. The rubber pushrod tube seals at the case shrink and harden and crack and shift around and start leaking, and the only fix is to replace them, which requires cylinder removal. Replace the gaskets at the case's seal fittings, too.

Sometimes magnetos get loosened to adjust the timing, and that mag gasket will usually get torn when the mag is rotated, since it's usually stuck, and thereafter it will leak. Those mags should be taken right off every 500 hours anyway. Very often a timing change will require a new gasket if it's been on there long enough to get stuck. The alternator/generator gasket can leak, as can the seal in the alternator/generator itself. The mag shaft seals can leak. The tach drive seal can leak. The vacuum pump drive seal can leak. The oil tank gasket can leak. All of it gets old, attacked by oil and the contaminants in the oil, and hardened by heat. Even the oil filler cap gasket gets old and tired.

If you had a car engine designed in 1938 you'd be chasing lots of leaks. Lycoming and Continental both have made big improvements over the years regarding engine sealing, but I still wonder why they aren't using a Viton or silicone O-ring in a groove at the magneto mounting instead of a gasket. Other places could use the same treatment. You can buy some neat stuff for your homebuilt engine, like this:
lycvc28sm.jpg




Oops. Got two pics and can't figure out how to get one out. Anyway, that's a Lyc rocker cover with an O-ring groove
lycvc28sm.jpg
for a viton O-ring. No more leakage. From these guys:
http://sdsefi.com/sdsaero.htm
 
I put the Real Gaskets spring loaded pushrod tubes on all six cylinders of my O-300-C (1963 C172D) when I put new ECi Titan cylinders on it, and it fixed the leaks from the original swaged pushrod tubes. My Zodiac has an O-200-A, and I was pleasantly surprised to see it was already equipped with the Real Gaskets pushrod tubes. No leaks.
 
I had a 56 172 with an 0-300 for 9 years. It had small leaks that bothered me but that my IA said to monitor but not worry about. I told him I really wanted it dry so I’d know right away if I had a problem. He was retired and agreed to mentor me by personally guiding and supervising me in doing what could be done to stop any leak I wanted to work on.

I spent time every month of the 9 years that I owned the plane ‘fixing’ one leak or another. In most cases we’d successfully stop the leak I was targeting, but before a month was up there would be another some place else.

None was serious, and the amount of oil I used never exceeded a quart in 3-5 hours, before or after I started ‘fixing’ leaks.

I did learn a lot about how to take care of a continental engine, but also realized at some point that I was never going to stop the 0-300 from having a small leak.

I think my IA’s recommendation to monitor the leaks and oil consumption to see if anything changed was the advice that I should have followed.

Gary
 
I’d keep my eye on it and “clear prop”, I fly your little sister the c85 but have your 0-200 jugs n such on her... I do all my own allowed maintenance and I clean my engine every oil change and look for anything that looks like a significant leak... she’s always a bit damp in spots and far from leak free... but nothing that would cause any concern.

Yes you can fix them but there’s two costs involved: the dollars to save a few drips of oil, and the increased risk of maintenance induced failures/issues. Even not going full Mike Busch I think stats would indicate I’m safer flying a normal amount of leakage c85 than having things taken apart n reassembled solely to save what is no more than a minor nucence that has no real negative mechanical effect on the engine.

until you feel comfortable making that call yourself get a second opinion from a recommended mechanic. Get the advice of seasoned o-200 operators then make your decision.

GeorgeC said:
My O200 allegedly has the real gaskets pushrod tube seals and does not leak.
Click to expand...

I will be doing these when I have cylinder work done. I’m at about 1000hrs on my cylinders and compression rocks 76 I think in 3 and 72 in one. There is some putting in that lowest one... but once they look like they are due I definitely want to do those. Just doesn’t make sense at the point in life my engine currently is in. Glad to hear more good reports
 
A couple of photos... The top photo is the Continental cylinder with swaged pushrod tubes.
CIMG0025.JPG

And here is an ECi Titan cylinder with the Real Gaskets pushrod tubes.
CIMG0069.JPG
 
Wow, thank you EVERYONE. Really appreciate this insight. What I've learned:
  • Yes, Continential engines leak. They will almost always be leaking oil from one place or another unless you invest massive money and time on the best replacement parts.
  • Even if you fix one location it's leaking from, you'll always find another the next time you fly it and it will be a constant game of 'whack a mole'.
  • How MUCH they leak is all that's important. As long as you aren't adding oil too often and your Ts & Ps are good during flight (and you don't mind cleaning up the oil that drips all over your plane), you're good.
  • Continental says that acceptable oil consumption of an O-200 is half a quart per 3 hours. To me, that's akin to them admitting the engine leaks because there is no way the engine is going to burn half a quart in 3 hours! It must be leaking for that much to escape. So Continental is admitting without admitting that it leaks and is normal as far as I'm concerned.
  • Ultimately, as long as you're filling half a quart or less per 3 hours of flying, and your oil temp and pressure is good while in the air, you have a perfectly running engine.
  • I will make peace with having an engine that isn't completely dry on the outside as long as I own a Continental or Lycoming.
 
kicktireslightfires said:
  • Continental says that acceptable oil consumption of an O-200 is half a quart per 3 hours. To me, that's akin to them admitting the engine leaks because there is no way the engine is going to burn half a quart in 3 hours! It must be leaking for that much to escape. So Continental is admitting without admitting that it leaks and is normal as far as I'm concerned.
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I would not interpret it that way. ALL engines burn oil, it is a matter of how much. If your main exposure to engine operation is late model cars and the miniscule amount of oil they typically consume, the amount of oil an aircraft engine can/will burn is huge in comparison.
 
kicktireslightfires said:
  • Continental says that acceptable oil consumption of an O-200 is half a quart per 3 hours. To me, that's akin to them admitting the engine leaks because there is no way the engine is going to burn half a quart in 3 hours! It must be leaking for that much to escape. So Continental is admitting without
Click to expand...

If an engine is really tired it could easily burn half a quart in three hours. It would be pretty worn out. And the plugs would be fouling badly.

When I flew a glider tug in the 1970s, the old Gipsy Major engine in it burned (and leaked) a quart of Aeroshell 100 per hour. We switched to Texaco, and it "only" burned half a quart per hour.

Texaco discontinued aircraft engine oils long ago. Too bad. It was good stuff.

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mondtster said:
I would not interpret it that way. ALL engines burn oil, it is a matter of how much. If your main exposure to engine operation is late model cars and the miniscule amount of oil they typically consume, the amount of oil an aircraft engine can/will burn is huge in comparison.
Click to expand...

That has not been my experience, albeit I have limited experience and only with the O-200-D. But in the last 40 hours of Hobbs time, my O-200-D has not burned more than half a quart (and Continential is suggesting half a quart in just 3 hours in normal?!). I had an oil change done right when I got it, we filled it to 5 on the dipstick and just did another oil change and it was at 4.5 and I hadn't added any oil since the last oil change. So the amount of oil consumption must be extremely small given there has also been a fair bit dripping out from below.

FYI my O-200-D is only 10 years old and just under 500 hours tach time since new.
 
kicktireslightfires said:
That has not been my experience, albeit I have limited experience and only with the O-200-D. But in the last 40 hours of Hobbs time, my O-200-D has not burned more than half a quart (and Continential is suggesting half a quart in just 3 hours in normal?!). I had an oil change done right when I got it, we filled it to 5 on the dipstick and just did another oil change and it was at 4.5 and I hadn't added any oil since the last oil change. So the amount of oil consumption must be extremely small given there has also been a fair bit dripping out from below.

FYI my O-200-D is only 10 years old and just under 500 hours tach time since new.
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My O-200 with about 850 hours burns less than a quart per 25 hour oil change as well, and it also has some small leaks, most likely from the pushrod tubes. The pushrod tube leaks only started in the last year, so new leaks do pop up from time to time.
 
kicktireslightfires said:
That has not been my experience, albeit I have limited experience and only with the O-200-D. But in the last 40 hours of Hobbs time, my O-200-D has not burned more than half a quart (and Continential is suggesting half a quart in just 3 hours in normal?!). I had an oil change done right when I got it, we filled it to 5 on the dipstick and just did another oil change and it was at 4.5 and I hadn't added any oil since the last oil change. So the amount of oil consumption must be extremely small given there has also been a fair bit dripping out from below.

FYI my O-200-D is only 10 years old and just under 500 hours tach time since new.
Click to expand...

It still burns more than your car, which was my point. Further, I would be surprised if any manufacturer considers leaks as normal and factors that into the consumption equation.

What Continental is suggesting is that burning half a quart in three hours is still acceptable, not a goal.
 
mondtster said:
What Continental is suggesting is that burning half a quart in three hours is still acceptable, not a goal.
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Continental also says that differential compression tests as low as 40/80 are OK. They seem to be trying to make excuses. Low compression due to worn rings is one thing; due to leaking valves, especially exhaust valves, is another animal entirely. You can fix a leaking valve; you can't fix one that has leaked enough that it finally burns badly in flight and results in power loss and expensive cylinder work, or even worse, that valve loses its head and trashes the piston and head and cylinder and maybe the con rod and other stuff. And broken debris from that cylinder gets blown out the intake and is sucked into other cylinders.
 
Dan Thomas said:
They seem to be trying to make excuses.
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Perhaps, but they're not the only ones. Lycoming has a similar absurdly high number for acceptable oil consumption, and it is not uncommon to find engines from either manufacturer that will burn oil close to those figures. Is it acceptable? Maybe or maybe not. I'd want to assess the whole engine to determine its health rather than going solely off oil consumption rate.
 
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