Using oil dye with UV light to find oil leak

I'm trying to chase down an oil leak and I'm thinking of using a fluorescent oil dye and an ultaviolet light to find the location of the leak. I'm wondering if anyone has experience with this approach and if so, 1) did it work and 2) are there any tips for doing this? Any help will be appreciated.

I gave dye and a UV light a try years ago without success. Not sure if the dye was old and bad, if the light source wasn't right (I *thought* I had the right light), or what. All I know is that it didn't work for me.

One of the better suggestions I've seen is to thoroughly clean the engine, then run it briefly and dust it with talcum powder. The talc will adhere to any exposed oil, and hopefully you can trace that back to the source.

uv light

Like Kyle, I used the UV light some years ago and it worked fine for me!
I followed the instructions, which I don't remember, but I do rember seeing
the cool colored oil......yes, it did work for me.
but I also did the wash down real good and run briefly trick too!
I hate oil leaks!
Sometimes they are real hard to find.
check oil drain back lines from the cylinders.
and the base of the oil filler/dipstick tube. my gasket was missing.
pushrod seals
and the oil line fittings on the rear case, actually put a wrench on them!
ask me how I know!

leak

I too have used the dye with the UV light to find a leak. Typically, I find loose clamps on the oil return lines, loose cylinder head rocker cover gasket screws, and in short, anything that is not metal tends to contract and shrink a little here and there after a year of flying. I also replace all my customers cork gaskets with rubber ones, you try peeling off the old cork gaskets after they are oil soaked and cooked on and you will see what I mean. I wash down the engine with mineral spirits (I make sure not to get ANY in or near the vac pump)first with a pressure sprayer, put the dye in, run it for a short period of time and look at everything with the UV flashlight (at night). I've never used Talcum power as I've not analyzed it for corrosive ability, however I'm sure it works like a charm....
Best
Brian Wallis

Rv's don't leak oil, they are just marking their territory.

Another way

to spot leaks after washing and a short run is to spray it down with the developer part of a dye penetrant kit.
Good Luck

Andrew
-4 started and sold
dreaming again
A&P I.A.

awm said:

to spot leaks after washing and a short run is to spray it down with the developer part of a dye penetrant kit.
Good Luck

Andrew
-4 started and sold
dreaming again
A&P I.A.

Click to expand...

I agree with this. For years that has been my trick on large aircraft to find leaks of oil, fuel, or hydraulic. Clean it up real good and spray with the dye penetrant developer. The developer will turn white when it drys. Any leak shows as making the white go transparent. When you are done it washes off with Stoddard solvent or similar. Much better than messing with the dye etc.

Don

How about pressurizing the case?

I read about another technique to find oil leaks. Pressurize the case using a (clean) shop vac on blow (have to come up with some method of plumbing the vac hose to the breather outlet). Then you go around with a spray bottle of soapy water spraying and looking for bubbles.

Any reason this won't work?

Any of you folks ever tried this?

John Miller
RV-8A
Fairbanks

Hasn't been warmer than 35 below here for the last 15 days - gives lots of time to think up goofy ideas!

You don't need dye

You don't need the dye to see an oil leak with ultraviolet light. The oil fluoresces just fine under UV light without dye added; in fact, it glows a nice iridescent light-blue.

I had a slight seep from my oil pressure regulator cap and played my UV light on the engine at night in the dark hangar and it was amazing to see where all the places the oil had migrated to.

Heinrich Gerhardt
RV-6, turned 200.0 hours on shutdown today!

AD aircraft oil already has the dye in it

At least Aeroshell does. We use it here at work for flow visualization: spread the oil, turn the wind tunnel on, take pictures with strong UV flash. The oil flouresces very well. Need dark background and low ambient light of course.

I had an oil leak that was driving me nuts. I put UV dye in the oil and went over it with the black light. It showed me where the leak wasn't, but not where it was. I found it when I began removing the cool baffles. The leak was from a crack in a cylinder barrel, about half way up the ring wear area of the bore. The crack extended about 120? around the barrel, more or less parallel with the cooling fins. The crack would not open up and leak oil unless the engine was under power. I'm thinking maybe one more flight and it would have separated in flight. My point is, keep bird dogging your leak til you find it. It may be just a nuisance or it just may be a symptom of impending catastophic failure.

When you guys have done this, how long in minutes is the “short run”? Do I need to just run it for a minute or do I need to taxi at takeoff power down the runway?

FIRST and foremost clean it like you are going to be eating off it. I use spray brake cleaner by the case (it seems like) when I'm chasing a leak. UV light works real good in the DARK. Any ambient light sorta kill the effect.
My IO 360 seemed to be always wet somewhere. till I set about a program of fix clean fix clean etc etc.
How long you run it depends on the leak. Fire up, warm up, shut down, look, clean clean clean.
I found leaks everywhere. Mostly have them fixed now. I think ha ha ha
After you get the big ones then run it longer.
My three cents Art