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OIL DYE/BLACK LIGHT

larryMar

Well Known Member
Has anyone had success with dye/blacklight to find nagging leaks? Is it safe for stock lycoming/rsa/mag/gov? Is it recommended to immediately change the oil/filter afterward or is it ok to fly with for further investigation?

Thanks,

larry
 
I believe most modern oils will fluoresce under a black light without any additional dye. I know AS W100 will for sure, as I’ve done it in the past. The newer the better, though.
 
I can also confirm that Phillips XC 20W-50 also glows green with black light...no additive needed...also the new the better.
 
Dyes, such as AutoPro or Tracerpro (available at Autozone and O'Reilly, and likely any parts store or Walmart) will not have any affect on the oil, so using the additive is fine.

If you wear a set of yellow lens safety glasses, it will help highlight oil under UV light, even without the dye.

The dye will break down over time and you don't need to change the oil afterward; just keep your normal change interval.

If you're trying to find a pesky leak, the dye will make it much more evident with a brighter green hue than compared to plain oil.
 
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I can also confirm that Phillips XC 20W-50 also glows green with black light...no additive needed...also the new the better.

I tried it and had no success. Maybe my UV flashlight wasn't emitting the right UV spectrum to make the X/C 20W-50 fluoresce. :confused:
 
key to problem

One of the key things I find when trying to get the pesky leak found is to get the offending area CLEAN.
Get a few cans for non-chlorinated spray cleaner, brake cleaner, electronics cleaner, ETC and clean the %&#$ out of the area.
Do short run up, if no show, run longer. and so on.
But "clean" is the key.
I buy the stuff by the case and close my eyes to the cost blowin in the wind as I spray a half can out.
A guy across our taxi way, Goes "WOW" that stuff is really cool. Gotta get some. So I gave him a can.
It is available at any parts store or Amazon
Clean it like you're gonna eat off it.
My three cents worth. Art
 
The dye helps significantly

Makes it light up like a disco.

Note to self. When using it in fuel for tank leak checks, it will wick up the surfaces to unfilled rivet holes. You will panic and curse before realizing what happened.

Edit = Its use would seem to minimize any efforts (cleaning) required to differentiate new versus existing oil depos. Reference previous post
 

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I tried it and had no success. Maybe my UV flashlight wasn't emitting the right UV spectrum to make the X/C 20W-50 fluoresce. :confused:

I've got two UV flashlights - one at 345nm and one at, I think, 340.

They both work, but the oil seems brighter/more contrasty on the 345nm one.

You also really need it as dark as possible. Even at night, with the lights off in my hangar, I get enough ambient light from outside sources that it diminishes the glow effectiveness. I take a couple of moving blankets and cover the motor and then get under them. It helps a lot.

Without this, I never would have noticed that my fuel pump was leaking. I am now trying a couple of other options before I replace it.
 
I've got two UV flashlights - one at 345nm and one at, I think, 340.

They both work, but the oil seems brighter/more contrasty on the 345nm one.

You also really need it as dark as possible. Even at night, with the lights off in my hangar, I get enough ambient light from outside sources that it diminishes the glow effectiveness. I take a couple of moving blankets and cover the motor and then get under them. It helps a lot.

Without this, I never would have noticed that my fuel pump was leaking. I am now trying a couple of other options before I replace it.

It definitely wasn't dark when I tried it. Next time I have the cowl off I'll try again utilizing your suggestions and see if that helps any.
 
I got an idea

Our most senior A/P said take a spray bottle, fill it with isopropyl alcohol,
clean area with same really well , dump some talc in the bottle, shake, spray on effected area, look for oil.

Never tried it. Other than making a mess, it might work . John
 
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