Tiny oil streaks on prop hub

[RobertE]

I know that an oil streak on the prop is evidence of a leaking seal. I don't have that. What I do have are tiny, hairline streaks on both prop hubs. In other words, the flat surface from which the prop emerges (about 1/4 inch wide) shows very faint streaks to the edge of that surface. What gives me pause before simply concluding I've got a leaky seal is the fact that the hub on both blades shows identical evidence, plus the fact that there isn't enough oil to be noticeable except in direct sunlight. I can't imagine both seals failing simultaneously and identically. The prop was overhauled 200 hours ago.

So do I have a problem and, if so, should I take it immediately to the prop shop or first watch it for awhile?

[romair]

Have the same thing, very faint streaks. I had them before and after prop overhaul. I think it's normal.

Stefan

[Jeev]

Its normal especially in hot weather.  Unless its leaving oil mist on your windshield or cowling I wouldn't worry about it.

[BorealOne]

Same thing happened to me after a new prop was installed. It's simply some excess grease working its way out. I'd say nothing to worry about.

[aaronk25]

Same here....200hours since overhaul and oil streaks

[animalmover]

There was a discussion a while back about this and if I remember correctly it had to do with the type grease in the prop and the hot part of the year. Places in the north were using lighter grease and the people in the south were using heavier.

[Scott Aviation]

Same issue on my 201 pulled the prop twice this summer thinking the hub oring was leaking strange it only started during hot summer conditions although I am getting the odd speckles on the windshield too. Little streaks about 3 " up at the base of the blades on both blades. Confirmed it's not the prop oring so it's the warm grease in the blade hub?

[Scott Aviation]

And to note my prop was overhauled in 2008 and has 180 hours in service the McCauley paddle prop

[Cody Stallings]

With the 200 Series McCauley, after overhaul you may have a blade that needs to be re shimmed. If a blade has excessive blade tip movement, it will allow the blade to wobble just a tiny bit during shutdown allowing the blade Oring to move up an down on its sealing surface. The small amount of greese that got on the outside of the Oring will sling up the blade on the next start up.

It is not uncommon for a McCauley to be re shimmed after Overhaul. An no, it is not a safety of flight issue.

[larryb]

I have faint streaks too. Many start halfway up the blade. I thought they were bug guts.

[Rhumbline]

If ever there was a case for the use of prop wash...

[rob47v]

It's normal and as someone mentioned specially during the summer months. It's grease gets hot thins out and streaks on the prop. If it where oil from the hub then worry. One of my neighbors had the same thing on his 172. I told him what it was. Not comfortable had the prop looked at. $2200 later it did the same thing the shop told the same thing I did that it was normal. WOW!!!!  

[RobertE]

Thanks, gentlemen.  This is another reminder of how terribly helpful this forum is.