C-145 (O-300A?) Heavy Leak/Drip & Tach Question

[GAHorn]

It's not a birth-defect... it's a "mutation". (It's parentage was immaculate!)

[rusty]

I The 172 has the wheel growing out of the wrong end. Started around 1956.

[blueldr]

Cessna built the 172 so that women could get in to the game!

[N4281V]

BL -

Are you saying women can't fly a 170?

I can get in mine and fly it just fine, even if it lacks the cabin entry step from a long ago removed nose gear STC installation....

PS I also hold an ATP along with being a CFI/CFII for 20+ years.
(I assume you are joking.....)

I've been helping my A&P/IA hubby for 20 years and I would say that "heavy leak/drip" is not normal and needs to be investigated by a mechanic. Listen to your plane, it's trying to tell you something!

Fly on!
"Wicked" Ann

[GAHorn]

ME...joking, ..while addressing ground-school in which a not unattractive brunette was attending:
"If God had meant women to fly...He'd have made the sky PINK!"

Without missing a beat, she replied: "Clearly you haven't been watching sunrises and sunsets lately!"

Touche' !

[ptporebski]

Hello Again Everyone:

I am under a hard deadline to complete my instrument training (must complete by 3/31/15 or need to take the written again). So I have been trying to keep the plane in service, otherwise I would gladly take it apart. I am changing the oil and took the opportunity to take the cowling off and shoot some pictures of the apparent leak. There is no leakage from any of the push tubes - None at all. The leakage seems to be coming from the horizontal flange/seam of the carburetor. Most of the seepage/leakage is on the pilot’s side of the carb. Pictures are attached. I will post this on the hanger forum and try to put pictures on too. But I would welcome what others think of this. Thanks.

... Well, I tried to reduce the size of the picture but even at the lowest setting apparently, the file has too many pixels... Drat!!

Regards,
Pete P.
1959 C-172

[c170b53]

I had to re-read things and I see I was just as guilty as Bruce for not fully digesting what was reported. So if I understand correctly the oil is around the outside side of the carb. The seam; possibly you're describing where the carb float bowl is attached to the top of the carb.
Blue - green fluid, likely low time oil leaking from somewhere. Probably leaking all the time but more noticeable if air flows haven't had a chance to distribute it evenly throughout the engine bay.
Remove cowls, dry it all off and run the engine for a few minutes. Try to determine whether the oil is coming from the rear cases or from above the carb. Above and you likely have a bad sump, from the rear you'll have to narrow it down to either the tach drive, mags, starter or gen pads.
What's your oil consumption? Basically if you can complete your missions and still have sufficient oil, I would think your good to go until you have a suitable maintenance opportunity to fix it.

[hilltop170]

Also, check all of the carb hold-down studs and bowl bolts for tightness. I have had the bowl shake loose before, even with the tab washers locked in position. I think the gasket collapsed or something. The blue-green stains/goo could be evaporated avgas that has leaked out, evaporated, and concentrated the dye to where it is visible.
Good luck.

[170C]

If the previous suggestions don't solve the puzzle, go to NAPA & buy a bottle of dye (made to locate leaks). Wash the engine down and put the dye in the oil sump, either run the engine until the oil temp is up to 140 or so OR go fly for 10-15 minutes to get the oil hot. Remember that hot oil will find places to leak that cool or warm oil won't. Then pull the cowling and use a black light to locate where that oil is coming from. You will need to have access to a dark hangar or check it at night so the black light will make the dye in the oil visible as a golden color. Success!

[voorheesh]

With all due respect for the expertise on this forum, you need to find a qualified/certificated aircraft mechanic to troubleshoot and hopefully repair your problem. At the airplane, not on the internet. I think that somewhere in central Florida, there has to be someone who could help you. Engine leaks such as you describe can be dangerous in that they can cause fires, failures, problems when you least need them. There is no reason for you to fly this aircraft until you get it fixed. This is a great forum with a lot of experience but your descriptions, even if you can figure out how to post a photo, are simply not sufficient to intelligently understand what is going on in your airplane. I used to make my living investigating aviation accidents and this thread is starting to worry me. Its reminding me of some not so pleasant episodes. Sorry, but I had to say something.

[hilltop170]

Re-reading the initial post on this thread seems to indicate a significant volume of this mystery blue-green fluid is leaking from this engine. Like voorheesh says, something is wrong that needs to be found and corrected. Simple weeping of gas around the carb won't produce the amount indicated by ptporebski.

I appreciate voorheesh's opinion about being cautious and finding a professional solution to this problem. I agree with that opinion. However, I disagree with voorheesh about the discussion in this thread. This problem has been occurring for a long time and an IA has been involved from the start, changing the carb, etc. Just because a guy is an IA doesn't mean he has or can think of all of the possible solutions. The owner might not be willing to pay an IA to sit and think of all the possibilities for a solution to the problem. The ideas thrown out on this forum may not be politically correct per the FARs and don't need to be because we are not all certified IAs. That doesn't mean forum users don't have good ideas or that their ideas should not be shared. That is what the forum is all about. What the owner does with the ideas is his choice and hopefully he will handle things the right way. But again, he is not being directed to do anything by anyone, this is a discussion of ideas and opinions, not directives to take action.

Back to the topic of sharing ideas, the primer is the only other source I can think of that will supply the amount of gas needed to produce the reported volume of the blue/green fluid coming from the carb and air box. Leaks in the carb itself will not collect above the carb bowl or in the intake manifold, gravity prevents that. If the primer is leaking thru for some reason, gas could, over time, accumulate in the intake and slowly evaporate leaving behind the blue/green goo. Then, when the engine is run, the fresh gas could dilute the goo and allow it to run out of the intake manifold into the carb and out the airbox.

Another long-shot idea I can think of is what kind of oil is being used in that engine? I have seen some non-aviation motor oils that were dyed different colors. Could that be the source of the off-color leaks? Minor oil leaks don't usually cause any big problems in themselves or there would not be any radial engine airplanes left flying.

[voorheesh]

I did not intend to diminish any of the valuable advice offered in this thread particularly from Hilltop, Bruce, and Jim Macintosh. All that advice is helpful and should continue. The problems I see are: This pilot appears to be trying to troubleshoot his problem on a forum and is not obtaining qualified help at the actual airplane. If his IA could not help him identify the source of a serious leak problem, he should get a second opinion. Any decent IA should suggest this if they run into a brick wall. A leak such as this is a safety of flight issue. No one should suggest to a pilot that it is ok to take a flight with such a condition based on an internet conversation. Do we know this guy? His experience? I have seen serious (fatal) accidents where the pilot should never have attempted to fly in the first place. These include engine failure following takeoff where the pilot had knowledge of a mechanical discrepancy and took a chance based on uninformed faulty advice from "friends". I investigated an accident where a private pilot elected to fly an airplane that he knew had a serious problem, that he attempted to fix himself, that caught fire after takeoff and seriously injured (almost killed) his innocent passenger on her first experience in a general aviation flight. That is my concern here. Now if he were to find a qualified mechanic (meaning experience, knowledge of, proper tools, and guidance on Continental engines) and if that technician investigated the problem and advised the aircraft was airworthy and needed to fly in order to obtain more history on the leak problem, that would be an acceptable course of action. Our advice should emphasize that and not give this pilot a false sense of security that he can make these decisions on his own. (caveat: another problem with internet communications could be missing information. If this original poster is a qualified mechanic but did not tell us that, my opinions become invalid).

Now regarding "political correctness" and the FARs. The FARs represent the minimum level of aviation safety. The FARs are necessarily legalistic and should not be confused with the elements of aviation above the "minimum level" where most of us exist when we fly. Most accidents occur during technically legal operations. So please do not misinterpret my comments as attempts at political correctness or defense of the FAA. I respect the FARs and do my best to comply, but my concerns here involve aviation safety and accident prevention. The FARs are only the threshold. Accidents usually involve multiple factors including safety culture and everyone involved with the Cessna 170 org contributes to that within our group. I believe we have an excellent safety culture but need to be careful with our words so we avoid inadvertently sending the wrong message or, worse, providing justification for a dangerous decision.

[sfarringer]

I tend to think that when there are indications of a significant fluid leak, the decision whether it is safe to fly can only be made (by an appropriately rated person) after determining the exact source of the leak. Troubleshooting leaks is not always easy, but it is important. Some leaks can hurt you.

[hilltop170]

I did not intend to diminish any of the valuable advice offered in this thread particularly from Hilltop, Bruce, and Jim Macintosh. All that advice is helpful and should continue. The problems I see are: This pilot appears to be trying to troubleshoot his problem on a forum and is not obtaining qualified help at the actual airplane. If his IA could not help him identify the source of a serious leak problem, he should get a second opinion. Any decent IA should suggest this if they run into a brick wall. A leak such as this is a safety of flight issue. No one should suggest to a pilot that it is ok to take a flight with such a condition based on an internet conversation. Do we know this guy? His experience? I have seen serious (fatal) accidents where the pilot should never have attempted to fly in the first place. These include engine failure following takeoff where the pilot had knowledge of a mechanical discrepancy and took a chance based on uninformed faulty advice from "friends". I investigated an accident where a private pilot elected to fly an airplane that he knew had a serious problem, that he attempted to fix himself, that caught fire after takeoff and seriously injured (almost killed) his innocent passenger on her first experience in a general aviation flight. That is my concern here. Now if he were to find a qualified mechanic (meaning experience, knowledge of, proper tools, and guidance on Continental engines) and if that technician investigated the problem and advised the aircraft was airworthy and needed to fly in order to obtain more history on the leak problem, that would be an acceptable course of action. Our advice should emphasize that and not give this pilot a false sense of security that he can make these decisions on his own. (caveat: another problem with internet communications could be missing information. If this original poster is a qualified mechanic but did not tell us that, my opinions become invalid).

Now regarding "political correctness" and the FARs. The FARs represent the minimum level of aviation safety. The FARs are necessarily legalistic and should not be confused with the elements of aviation above the "minimum level" where most of us exist when we fly. Most accidents occur during technically legal operations. So please do not misinterpret my comments as attempts at political correctness or defense of the FAA. I respect the FARs and do my best to comply, but my concerns here involve aviation safety and accident prevention. The FARs are only the threshold. Accidents usually involve multiple factors including safety culture and everyone involved with the Cessna 170 org contributes to that within our group. I believe we have an excellent safety culture but need to be careful with our words so we avoid inadvertently sending the wrong message or, worse, providing justification for a dangerous decision.

Agreed.

[GAHorn]

Harlow's comments are good and well intentioned, and his past experience investigating accidents doubtless flavor his concerns.
There is one thing I'd like to add, as regards obtaining advice from the forums..... There are many many hundreds of certificated A&P's who are not well versed in all types of troubleshooting, and many that I've personally found to be incompetent in the extreme with repairs...yet they have that "ticket".
On the other hand, we all know the majority of those who have been "in the business" for many years only survived that long because their reputations as trouble-shooters and repairmen support them well.

I believe that a great many of the participants and Members of this forum are highly qualified, regardless of whether or not they are "certificated"...and are certainly qualified to offer valid advice on how to troubleshoot problems. Anyone who has read the "disclaimers" of these forums should recall that no advice here supercedes or replaces approved data or procedures, and anyone who works on their certified aircraft should do so only under the direct supervision of a certificated repairman (or under their own certificate, if applicable.)

Having said that, I wish to lend support to Richard's comments (and others) here. I don't think it's disqualifying for an owner to troubleshoot his own aircraft as long as no REPAIRS or DISASSEMBLY/REASSEMBLY are undertaken except under the direct supervision mentioned above. I encourage owners to participate in all aspects of their aircraft's maintenance. Let's just all agree that no actual work will be performed except in accordance with FARs.

(Meanwhile, if it hasn't already been suggested.... I'd like to remind the OP that the oil sumps have a history of corrosion in the immediate area just above the carb mounting, and that if your engine has a serious leak, indicating both oil and fuel in this area.... to consider the possibility that the oil sump may have been compromised in this area. Until that possibility has been investigated and removed, then be very cautious about operating this engine in flight.)