Any success with external sealers?

Chip Sylverne

Chip Sylverne

Final Approach
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Quit with the negative waves, man.
After doing some chasing down, I've finally found the last source on my O-540's oil leak. UV dye revealed it's coming from the seam where the accessory case meets the oil sump on the left rear corner of the case. The bolts are tight. I'm assuming it's the result of removing the accessory case to install a Johnston counterweight stc. The rest of the engine, case halves, jug bases, oil return tubes, etc, etc.etc. are tight.

Since this would be muyexpensive to reseal, and would buy a lot of oil, I'm willing to live with it leaking a few drops. But I was wondering if anybody has had any success with externally applied sealers, like Permatex 82099, Hylomar or the like applied to the outside of the seam to slow it down.

Thanks
 
No idea, but I would try something I think.

What have you got to lose besides a $10 tube of goop and a little time. :wink2:
 
I know a guy who found this process to seal his leaky case seam which, as I remember, involved hooking a shop vac to the filler tube and I suppose blocking off the breather line then applying some sort of Permatex sealant.I was skeptical but he swore it worked. I haven't talked to him for awhile though so don't know what the long term results were.

I recall that when I was doing online searches for the process I came across some similar documents for sealing floats so possibly there is some merit to it.
 
Silvaire said:
I know a guy who found this process to seal his leaky case seam which, as I remember, involved hooking a shop vac to the filler tube and I suppose blocking off the breather line then applying some sort of Permatex sealant.I was skeptical but he swore it worked. I haven't talked to him for awhile though so don't know what the long term results were.

I recall that when I was doing online searches for the process I came across some similar documents for sealing floats so possibly there is some merit to it.
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I can see that working if you applied a vacuum inside the engine and sucked the sealer from the outside into the cracks.

Worth a shot. Do it!

Let us know how it turns out. :yesnod:
 
I had a leak in the case seam on the top of my IO520, did the vacuum and Permatex deal. Worked great.

$0.02.
 
Silvaire said:
I know a guy who found this process to seal his leaky case seam which, as I remember, involved hooking a shop vac to the filler tube and I suppose blocking off the breather line then applying some sort of Permatex sealant.I was skeptical but he swore it worked. I haven't talked to him for awhile though so don't know what the long term results were.

I recall that when I was doing online searches for the process I came across some similar documents for sealing floats so possibly there is some merit to it.
Click to expand...

Now that's what I'm talking 'bout!
This is why I love this place. I never would have come up with this on my own.
Anybody got a clue which Permatex product?

Yes, I will try it.
 
Here's description of how one guy got it done - this is what I did. YMMV.

---

"First you'll need a few supplies, stuff thats good to have at the hangar anyways.
MEK for removing oil.
Loctite 290 It's a capillary action sealer. Graiger #5E216 $11.85
Lostite 515 Is a gasket eliminator flange sealer Grainger #5E226 $17.60
Stainless steel 1/2" plumbers fitting brush to clean I.D. of bolt holes
Shop vac
Latex or nitrile gloves
I purchase the Loctite stuff from Grainger, Napa may also carry it.

For your repair I would first remove the two case bolts where you see the leak, Then clean the I.D. of the holes with the stainles brush, then soak the corner of a rag with MEK and push thru holes with small screwdriver or similiar.

Now clean bolts, nuts and washers with MEK and top of case above bolt holes.

Now the optional part, To get a good seal parts have to be as oil free as possible. I do this by removing my oil fill cap, putting my 5 gal. shop vac hose in filler pipe and turn it on. This puts the crankcase in a vacuum To flush the oil out of the leak area.Then run MEK soaked rag thru holes again. I even apply some MEK with a spout oiler. I say this part is optional because I don't know how wise it is to run a vacuum around highly flammable MEK.
The next part has to be done start to finnish in a few minutes as 290 sets up fairly quick. set a couple rags along top of engine to catch excess 290 as it is very runny. Apply 290 to I.D. of bolt holes with a soaked Qtip. Don't skimp, most will run out,But apply a few times. Also apply along top of case halves above bolts.
Now fill holes with 515 and also goop up bolts with 515, object is to fill void around bolt as much as possible, thin latex or nitrile gloves come in handy here.
I hold the washer against the case as I push the bolt thru, this will keep most of the 515 in the hole. Quickly tighten nut and bolt to slightly above spec. Clean up excess 515 with a dry rag and let cure overnight. Cross your fingers :pray:

This has worked for me 3 for 3 times, all on different Continental 520s. These were all leaking at bolts and case split line above bolts. If you don't have any sign of leakage at split line, you may want to just fill bolt holes with 515 one at a time.

Greg"
 
So you guys are doing this with cold sealant applied to a cold case? It's an interesting idea but I'd think the case and sealant would benefit from being heated. When we do floats we thin the 5200 to allow it to flow into small spaces.

I'll be interested in whether it works. I'd clean the seam with aerosol electrical contact cleaner and compressed air and heat it with a heat gun before I applied thinned sealant. Good luck!
 
Let me show my complete ignorance. Wouldn't some sort of a gasket be easier and faster? Or is in an area where it's not possible to use a gasket?
 
Let us know if you succeed. In my experience, trying to stop an O-540 from marking its territory is an exercise in frustration.
 
Cheap overhaul leak oil, good overhaul's do not.:nono:
 
Stewartb said:
So you guys are doing this with cold sealant applied to a cold case? It's an interesting idea but I'd think the case and sealant would benefit from being heated. When we do floats we thin the 5200 to allow it to flow into small spaces.

I'll be interested in whether it works. I'd clean the seam with aerosol electrical contact cleaner and compressed air and heat it with a heat gun before I applied thinned sealant. Good luck!
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Heating with a gun is a great idea. What do you thin the sealant with? MEK? Acetone?
 
Depends on the sealant. In this topic I'd try heat first. We use heat to manage sealant viscosity in the winter in Alaska. It may apply here as well.
 
brien23 said:
Cheap overhaul leak oil, good overhaul's do not.:nono:
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True. But after 1000 hours...

I chased minor leaks for years on my O-540, and finally came to accept them as "corrosion control". lol. Bottom line: A teensy bit of oil can cover the engine, in a 150 mph wind, and life is too short!
 
Chip....once you get it good and clean, do mask off the edges with tape.....or it'll look like crap. :D

Denatured alcohol is the best for cleaning. It will not cut or disolve much....but is a great degreaser...or laugh, but 100LL is my favorite cleaner. :D


....and once yer done trying all that and it's still leaking, try Pro-Seal 870. :wink2:
 
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New information for me:
Some of you guys have lived with a leaking aero engine???
 
You could do it the right way.
 
It's pretty hard sometimes to figure out where your oil leak is actually at, and where the oil is, often isn't where it's leaking from.

Every spring I do the following with the Flybaby:

1.) I pour some 100LL into one of these:
8l_manual_pump_knapsack_pressure_sprayer_for_garden_weed_killer_vp_psb_8a-e23-VP-PSB-8A.jpg


2.) Then I pump it up and hope like hell it doesn't explode.

3.) Spray down engine and firewall real good with the 100LL (engine completely cold).

4.) Dump this into the oil:
7010040_idy_374cs_pri_larg.jpg


5.) Run engine for about 15 minutes

6.) Put engine in completely dark hangar, all lights off.

7.) Look at engine with one of these UV lights:
images


8.) Find all oil leaks. Fix all oil leaks.

9.) Spray down engine with 100LL again

10.) Run for 15 minutes again and look for oil leaks again

11.) Fix any that are still leaking

12.) Once no leaks, change oil.


YMMV, Yada Yada, the 100LL could explode on you. You could get burned bad. It has happened to people. Your airplane could start on fire.

There are less dangerous solvents you could use..but well..100LL is what I have..and I haven't exploded yet.
 
Jaybird180 said:
New information for me:
Some of you guys have lived with a leaking aero engine???
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lol Really?

Walk down the line at OSH. Get on your knees and peek at the bottom of every plane. You won't find very many clean cowls.

We aren't talking about measurable leaks that can be measured on the dipstick. We are talking more like seepage, but in a 150 mph slipstream, two drops of oil will totally trash the engine compartment.
 
I saw a pitot tube leak repaired with a shop vac and super glue. It was leaking around the electrode connection. It was a last resort and worked well.
 
Jay Honeck said:
lol Really?

Walk down the line at OSH. Get on your knees and peek at the bottom of every plane. You won't find very many clean cowls.

We aren't talking about measurable leaks that can be measured on the dipstick. We are talking more like seepage, but in a 150 mph slipstream, two drops of oil will totally trash the engine compartment.
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Maybe my preflight sucks, because I don't believe I've EVER flown behind a leaking engine. The front strut on my Skyhawk is a different story.
 
What's more dangerous? A seep/leak at the case half or trying to suck sealant into the void with no hope of any control of where the stuff ends up inside of the engine?
 
bnt83 said:
What's more dangerous? A seep/leak at the case half or trying to suck sealant into the void with no hope of any control of where the stuff ends up inside of the engine?
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I was wondering the same thing?
 
bnt83 said:
What's more dangerous? A seep/leak at the case half or trying to suck sealant into the void with no hope of any control of where the stuff ends up inside of the engine?
Click to expand...

you don't suppose he'll suck all that super glue in and.....super glue the crank in place? :yikes: :rofl::goofy:
 
bnt83 said:
What's more dangerous? A seep/leak at the case half or trying to suck sealant into the void with no hope of any control of where the stuff ends up inside of the engine?
Click to expand...

The directions Spike posted above, I interpret as, the vacuum not being on once you apply the sealant. Looks to me like the purpose of the vacuum is for the de-oil stage of the process.
 
Like with floats, I assume the negative pressure is to draw some sealant into the seam where it has a chance of being most effective. And like with floats, the chance that any sealant will penetrate through the full width of the seam is very unlikely. How effective any heat-softened sealer can be in this engine scenario is questionable anyway. A hardening compound like a gasket shellac may be worth considering. Honestly, the same old "which oil are you using" question should be asked. If you're using Aeroshell 15-50? Switch to a non semi-synthetic and see if the seep slows or goes away. That's the easiest fix there is.
 
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My guess would be the goop is so viscous the vacuum would make little to no difference. Like trying to suck a thick milkshake through a small straw. This is a seam seepage, not a hole in the case.

Using Aeroshell 100w plus.
 
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