New prop throwing grease

[Joe Larussa]

So I got a brand new McCauley prop for my 77 M20 J. It threw grease for almost 20 hours then stopped. Recently put 22 hours on it in 4 days and it started again. I’m not talking a ton, but leaving tiny spots on the cowling. Thoughts?

[Shadrach]

3 minutes ago, Joe Larussa said:

So I got a brand new McCauley prop for my 77 M20 J. It threw grease for almost 20 hours then stopped. Recently put 22 hours on it in 4 days and it started again. I’m not talking a ton, but leaving tiny spots on the cowling. Thoughts?

Weeping grease right out of overhaul is not uncommon.  Did the prop shop not mention this possibility to you?  Give them a call and explain the symptoms.  They will likely tell you to clean it up and monitor the situation.

[MikeOH]

I've had my prop OH'd and it still leaked...sent it back for a reseal...STILL leaks.  I've given up and just live with it.

You may want to ask what grease was used.  There was an issue with the Aeroshell 6 grease formulation change that can cause this.  To the point that Hartzell now allows you to mix Aeroshell 5 & 6, AND a new grease is also approved as the PREFFERED grease: NYCO GN3058.  https://hartzellprop.com/SERVICE-DOCUMENTS/SL/HC-SL-61-366.pdf

One day when I'm feeling sporty with my wallet (and my CB side is dead asleep) I'll send the prop in for a reseal and DEMAND they use the NYCO grease!

[Shadrach]

17 minutes ago, MikeOH said:

I've had my prop OH'd and it still leaked...sent it back for a reseal...STILL leaks.  I've given up and just live with it.

You may want to ask what grease was used.  There was an issue with the Aeroshell 5 grease formulation change that can cause this.  To the point that Hartzell now allows you to mix with Aeroshell 6, AND a new grease is also approved as the PREFFERED grease: NYCO GN3058.  https://hartzellprop.com/SERVICE-DOCUMENTS/SL/HC-SL-61-366.pdf

One day when I'm feeling sporty with my wallet (and my CB side is dead asleep) I'll send the prop in for a reseal and DEMAND they use the NYCO grease!

I don’t think any of the shops are using Aeroshell 5 anymore. In 2021, McCauley put out an SB similar to the Hartzell SB that you linked above. They are specifying Mobil 28.

[KSMooniac]

Definitely figure out which grease was used, and if it is Aeroshell you might want to have it removed and replaced with Mobil or Nyco as mentioned above.  I visited the Hartzell booth at OSH with a buddy that has a young Hartzell prop that slings grease from one blade.  The service rep told us the tale of Aeroshell grease and they finally had enough and switched to Nyco.  Their warranty claims dropped more than 90%.  (My friend's prop came with Nyco, so he's got something else going on that will be covered under warranty.)

[M20F]

If it is hot they are going to sling grease.  What was the OAT when all this was going on?

[0TreeLemur]

The Hartzell Top Prop we bought a couple of years ago came with NYCO grease, and a nice big sticker on the hub saying that was the only acceptable grease.   My A&P last annual said "What's NYCO grease?".   Luckily I bought some and a grease gun before the annual and gave it to him.

If only the paint would stay on the leading edge within 6" of the tip...  That's another story.    Some law firm could make coin organizing a class action on that one.  I know of several people here on MS that have the same problem with the paint on Top Props.

[philiplane]

On 8/11/2023 at 3:24 PM, Shadrach said:

I don’t think any of the shops are using Aeroshell 5 anymore. 

Aeroshell 6 was the problem grease, and replacing it with Aeroshell 5 fixes the slinging problem. Aeroshell 6 was specifically formulated for extreme low temperature operations. And they forgot how to make it after 40 years in production, so the oil would separate from the carrier and ooze through the prop seals. Aeroshell 5 is not affected. You can substitute 6 for 5, but you're limited to flying in warmer than -40C temperatures...

BTW- the NYCO grease is not a cure-all either. I've had several fresh overhauls, using this grease, seeping grease after 6-12 months/200 hours. Not bad like the Aeroshell 6, but enough to question the seals in the prop.

Edited August 13, 2023 by philiplane

[PT20J]

This is common. Excess grease on the blade bearings gets thrown out by centrifugal force. On mine, I saw some steaks on the faces (aft side of the blades). It came and went for probably 50 hours gradually decreasing until it finally quit. It depends on the temperature as the grease thins when it's hot.

[Shadrach]

1 hour ago, philiplane said:

Aeroshell 6 was the problem grease, and replacing it with Aeroshell 5 fixes the slinging problem. Aeroshell 6 was specifically formulated for extreme low temperature operations. And they forgot how to make it after 40 years in production, so the oil would separate from the carrier and ooze through the prop seals. Aeroshell 6 is not affected. You can substitute 6 for 5, but you're limited to flying in warmer than -40C temperatures...

BTW- the NYCO grease is not a cure-all either. I've had several fresh overhauls, using this grease, seeping grease after 6-12 months/200 hours. Not bad like the Aeroshell 6, but enough to question the seals in the prop.

I new that, just a misfire. I still have a tube in my hangar fridge that has leaked all over the inside of a freezer bag. The prop shops near me (Sensenich and East Cost propeller) seem to be eschewing Aeroshell products whenever possible. I heard that Aeroshell 6 was reformulated to meet an EU standard.

[A64Pilot]

Yeah, if it keeps slinging, eventually it will stop when it runs out  

I would say if not excessive that it’s normal for a few hours but then it ought to stop, 20+ plus hours I think I’d be calling someone.

We would flush the Hartzell props on all the new turbines we built then balance them, don’t try to flush a piston prop of course, but the new Hartzell’s the majority did sling minor amounts of grease for the first few hours but would stop pretty quick.

I’ve always been nervous about props that don’t need periodic greasing, but it seems to work.

[Joe Larussa]

On 8/11/2023 at 5:32 PM, M20F said:

If it is hot they are going to sling grease.  What was the OAT when all this was going on?

Was pretty hot I would say. Sacramento to Houston via Arizona. 

[Fly Boomer]

On 8/11/2023 at 8:26 PM, philiplane said:

Aeroshell 6 was the problem grease, and replacing it with Aeroshell 5 fixes the slinging problem.  Aeroshell 6 is not affected.

I tripped over the "6 not affected".  Bottom line:  6 is good and 5 is bad.  Correct?

I just bought the Aeroshell version of every lubricant on the lube chart -- hope I got the right stuff.

[philiplane]

was an auto-fill typo there...Aeroshell 6 is junk, but 5 is OK, and is is the replacement for 6. Should have read "Aeroshell 5 is not affected by the slinging problem"

Bonus- you'll only need one grease gun now, since 5 is also used as general purpose chassis grease.

[PT20J]

McCauley hubs are permanently lubricated, unlike Hartzell props which require annual greasing. McCauley hubs are either lubricated with grease during assembly or partially filled with red dyed oil. The red dye is for crack detection. I believe that the 2 blade hubs used on Mooney's are greased.

[OR75]

On 8/11/2023 at 11:10 AM, Joe Larussa said:

So I got a brand new McCauley prop for my 77 M20 J. It threw grease for almost 20 hours then stopped. Recently put 22 hours on it in 4 days and it started again. I’m not talking a ton, but leaving tiny spots on the cowling. Thoughts?

C212 or C214 ? a few tiny spots are not uncommon . Clean the front of the cowling well with solvent and take a picture of what it looks like  after an hour or two and send to installer 

if lots then sounds like a reseal maybe needed 

[Fly Boomer]

On 8/13/2023 at 12:41 PM, philiplane said:

was an auto-fill typo there...Aeroshell 6 is junk, but 5 is OK, and is is the replacement for 6. Should have read "Aeroshell 5 is not affected by the slinging problem"

Bonus- you'll only need one grease gun now, since 5 is also used as general purpose chassis grease.

Holy cow!  I re-read my question, and I reversed the two numbers in the question.  Thanks for clarification.