Blue on my cowl flap?

455 Bravo Uniform

455 Bravo Uniform

Final Approach
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455 Bravo Uniform
Could this be fuel staining? From where?

That’s plenty enough blue to have had a fire!?

Will pull the cowl to check it out.

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Here's a pic of a IO-470 for the mean time.
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Look at the fuel lines, obviously. I had a loose one on an engine driven pump once. Problem is, my plane is already blue, so hard to see on the outside.
 
Likely suspect is leaky fuel strainer/bowl assembly. It's right above the cowl flap and occasionally needs to be rebuilt. McFarlane rebuild kit pretty cheap, unless fuel bowl itself or other parts have corrosion, then plan on $300-$700 for parts depends what needs replacement.
 
NordicDave said:
Likely suspect is leaky fuel strainer/bowl assembly. It's right above the cowl flap and occasionally needs to be rebuilt. McFarlane rebuild kit pretty cheap, unless fuel bowl itself or other parts have corrosion, then plan on $300-$700 for parts depends what needs replacement.
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That's a real old strainer on that airplane. Parts N/A. The U bracket on the bottom that clamps the bowl against the upper body has a reputation of cracking through the clamp bolt hole, and the tension disappears and it leaks. Heaven help the pilot if it breaks off in flight.

We've replaced them with Steve's Gascolators: https://www.stevesaircraft.com/gascolator.php

Money better spent on new stuff rather than someone else's old parts.
 
How does a strainer leak reach the cowl flap leading edge?
 
Stewartb said:
How does a strainer leak reach the cowl flap leading edge?
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His Gascolator looks mounted right above the right cowl flap. Looks like the picture also shows blue staining on the lower front strut mount. I had a double whammy 9 months ago... both the Gascolator and aux electric fuel pump started dripping fuel. Both were mounted over the right cowl flap and I had a small amount of blue staining on the hangar floor one day.
 
I have very similar cowl flaps and gascolator. I doubt that's the cause. I'm interested to hear, though. Maybe a leak at a JPI fuel flow transducer? Hard to spot as it's wrapped in fire sleeve?
 
Guys, the pic that ktup posted is not my plane. No JPI either (yet; I wish). I have not even gotten to remove the top cowl yet.

I will check all the injector lines, as well as the return, supply, fuel pump, and gascolator. Hopefully it’s cheap.

On my to-do list is a prop balance. I get more vibration than I think is normal. Late last year I had an old copper fuel pressure (flow) gauge line crack and leak. Besides being old, copper, and probably work hardened, I suspect greater vibration than normal may have caused it.

A nice reminder for others is to clean the plane after every flight. I know the stain is new. Wouldn’t have found it if I didn’t wipe the plane down after every flight (the belly stays oily longer, I’m not that crazy).
 
If that's not your plane, then agree the problem is probably not gascolator. The cowl flap is stained and coated pretty well. You have a pretty heavy fuel leak that looks dangerous. Injector line or distribution regulator.
 
Stewartb said:
I have very similar cowl flaps and gascolator. I doubt that's the cause. I'm interested to hear, though. Maybe a leak at a JPI fuel flow transducer? Hard to spot as it's wrapped in fire sleeve?
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The fire sleeve would be stained.
 
455 Bravo Uniform said:
Guys, the pic that ktup posted is not my plane. No JPI either (yet; I wish). I have not even gotten to remove the top cowl yet.

I will check all the injector lines, as well as the return, supply, fuel pump, and gascolator. Hopefully it’s cheap.

On my to-do list is a prop balance. I get more vibration than I think is normal. Late last year I had an old copper fuel pressure (flow) gauge line crack and leak. Besides being old, copper, and probably work hardened, I suspect greater vibration than normal may have caused it.

A nice reminder for others is to clean the plane after every flight. I know the stain is new. Wouldn’t have found it if I didn’t wipe the plane down after every flight (the belly stays oily longer, I’m not that crazy).
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should be similar....not a 260se, but that's an IO-470 converted 182. Still hard to tell
 
FWIW I also don't think it's your gascolator. Mine had a pretty heavy leak (O-470) and the evidence of it was a puddle on the ground and blue staining down the belly, but nothing on the cowl.

That being said, if you're in there it's probably not a bad idea to do a redbuild kit on it. It was $13 for me and I did it owner assisted with my A&P since I've never taken one apart - even then it took less than an hour.
 
I tend to look for the more simple answer. You simply hit a smurf on takeoff or taxi. Just wipe it off, maybe morn a little, then on your merry way
 
We had a leak in one of the fuel lines as it had rubbed enough to go all the way through. $5 fix for us, naturally it cost a bit more to have it don’t by the AP.
 
Stewartb said:
How does a strainer leak reach the cowl flap leading edge?
Click to expand...

There is a lot of air blowing around in there in flight, and it's not all flowing nicely through that area and out past the flap. Leaking oil or fuel can end up in strange places, and gravity has nothing to say about it. I have found stains in some very non-intuitive places. Makes troubleshooting fun.

That said, it might not be the gascolator. Might be something on the other side of the engine altogether. Might be primer line fittings high on the firewall. Or a broken primer line somewhere. Might be a leaking carb drain plug. That picture doesn't help a lot.
 
455 Bravo Uniform said:
On my to-do list is a prop balance. I get more vibration than I think is normal. Late last year I had an old copper fuel pressure (flow) gauge line crack and leak. Besides being old, copper, and probably work hardened, I suspect greater vibration than normal may have caused it.
Click to expand...

Is it a Cessna? Cessna never used copper. They used Everdur, which was a copper-coated steel. It looks like copper and some mechanics have replaced it with copper, which is a mistake. Everdur is tough stuff and doesn't fail easily at all. Copper work-hardens real quick.
 
Dan Thomas said:
There is a lot of air blowing around in there in flight, and it's not all flowing nicely through that area and out past the flap. Leaking oil or fuel can end up in strange places, and gravity has nothing to say about it. I have found stains in some very non-intuitive places. Makes troubleshooting fun.

That said, it might not be the gascolator. Might be something on the other side of the engine altogether. Might be primer line fittings high on the firewall. Or a broken primer line somewhere. Might be a leaking carb drain plug. That picture doesn't help a lot.
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That stain doesn’t look like an in flight issue. Too localized.It looks like it had a leak in parking that’s probably already been addressed. But that’s just my opinion. You guys will surely tell me I’m wrong.
 
If your engine has a mechanical fuel pump, look for a small (1/8"?) hose coming off of it. If it leaks fuel down this hose, your pump has a ruptured diaphragm and needs to be replaced.
 
Dan Thomas said:
Is it a Cessna? Cessna never used copper. They used Everdur, which was a copper-coated steel. It looks like copper and some mechanics have replaced it with copper, which is a mistake. Everdur is tough stuff and doesn't fail easily at all. Copper work-hardens real quick.
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Yep, Cessna. I’ve seen the fuel P gauge lines replaced with braided hose, but the 2 A&Ps I talked to said the hard-line is the correct method. Whether it was copper before or not, don’t know, but it was replaced with copper.

Stewartb said:
That stain doesn’t look like an in flight issue. Too localized.It looks like it had a leak in parking that’s probably already been addressed. But that’s just my opinion. You guys will surely tell me I’m wrong.
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Pulled the top cowl at lunch. Didn’t see anything up top. You may be right. I don’t see anything inside of the bottom cowl, but need to pull it anyway to confirm all’s well.

This gives me a chance to do some paint touch up, and replace a few ugly CamLocs...gonna rain from tomorrow thru the weekend!
 
455 Bravo Uniform said:
Yep, Cessna. I’ve seen the fuel P gauge lines replaced with braided hose, but the 2 A&Ps I talked to said the hard-line is the correct method. Whether it was copper before or not, don’t know, but it was replaced with copper.
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I wouldn't fly it with the copper, and the mechanic should talk to Cessna's tech reps. Free advice. If that line breaks you could have a fire.

I had a 1/8" copper oil pressure line break on an old Champ. Those were the days when copper was used for a lot of stuff. By the time I landed it had blown three of the four quarts of oil overboard. Could have had a fire there, too. I later encountered an Aero Commander Lark that had a 1/4" oil pressure copper line and expressed concern. Nothing was done. It later broke in flight, blew all the oil overboard, and the engine seized.

Manufacturers use proper hoses for this stuff now.
 
Are there any drains on the intake manifold to get rid of excess fuel when priming? I'd be surprised if there isn't something. It could be draining somewhere inside the cowl and running down the cowl flap.
 
@Dan Thomas - I checked the other two “copper” looking lines and they are magnetic. My newer line being copper is obviously not. Gonna get that fixed. Thank you sir.

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Got the lower cowl off. Nothing found. A&P stopped by, did not find anything either.

Going to remove the blue and fly it in the pattern a bit.

The only thing we did different on the last flight was that it was my flight review and I wanted to try a couple of different emergency descents before we finished. We got over 2kFPM on one (did a big slip on one and then tried a banking sky diving maneuver on another...that was wild). Not sure that would have caused anything.
 
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