Light oil mist on front of cowl (M20J)

[bnicolette]

Hi all,

I am just starting to notice a very very faint mist of oil on my cowling behind the spinner?  Everything is working fine but apparently something is going to need some attention at some point pretty soon?  I am guessing that it might be coming from the prop and a seal job may do the trick?  If this is in fact the case, has anybody ever just done a reseal on the prop and not had it overhauled?  What are the costs associated with this?

Thanks all for any input.

 

[Skywarrior]

Might be a leak of the front crankshaft seal.

Chuck M.

[takair]

I've had both the crankcase seal leak and the prop leak.  If the prop, there is usually streaking on the blade and you will see or feel oil or grease inside of the spinner.  If the crankcase seal you can feel oil on the inside of the fly wheel/starter ring.  In my case that would leave a mist on the cowl and windshield. (I have an E model, so it gets out more easilly)  Some shops will reseal the prop, but may recommend o'haul if high time or many years since last done. To do the crankcase seal you have to remove the prop as well. 

[bnicolette]

Thanks guys.  I do remember my mechanic saying that, that seal was leaking just a little bit, and that was about a month ago.  And now that it is showing it's ugly face on my cowl, I think it is time to get it taken care of before I start to notice it on the windshield.  Has anybody had this done recently?  How much time does it take the mechanic to do it and whats the part cost?  I had him de-cowl the airplane after I had about 20 hours on the airplane just to make sure everything was looking okay.  He found a touch of oil around the mag and also the crankshaft seal area, so that has got to be what it doing it.

On the note of oil.........I am currently using Aeroshell 100W as that is what the previous owner had been using in it and thats what they put in during the prebuy/annual in February.  However, it was a Florida airplane and given the climate here in Southwest PA, I think I am going to change it out to Phillips XC and use Camgaurd.  Thoughts on oil???  Is there anything bad about the Phillips that I should consider not going that route?

Again, thanks for the input for a "rookie" Mooney guy.

Brett

[KSMooniac]

Phllips XC + Camguard is a great combo.  I switched a couple years ago after running A/S since Aviation Consumer heartily endorsed it and have been happy.

Before taking things apart, I'd de-cowl and thoroughly degrease your engine, and then run it for a few minutes and see if you can spot the leak(s).  It could come from somewhere unexpected and then migrate out...  I learned that the hard way after doing some maintenance that required me to loosen the top, aft crankcase bolt so that I could move the ignition harness.  I neglected to tighten that bolt completely on re-assembly, and oil from that area managed to migrate forward and out of my cowl!  It was a surprise to me...

[Shadrach]

Quote: Bnicolette

Thanks guys.  I do remember my mechanic saying that, that seal was leaking just a little bit, and that was about a month ago.  And now that it is showing it's ugly face on my cowl, I think it is time to get it taken care of before I start to notice it on the windshield.  Has anybody had this done recently?  How much time does it take the mechanic to do it and whats the part cost?  I had him de-cowl the airplane after I had about 20 hours on the airplane just to make sure everything was looking okay.  He found a touch of oil around the mag and also the crankshaft seal area, so that has got to be what it doing it.

On the note of oil.........I am currently using Aeroshell 100W as that is what the previous owner had been using in it and thats what they put in during the prebuy/annual in February.  However, it was a Florida airplane and given the climate here in Southwest PA, I think I am going to change it out to Phillips XC and use Camgaurd.  Thoughts on oil???  Is there anything bad about the Phillips that I should consider not going that route?

Again, thanks for the input for a "rookie" Mooney guy.

Brett

[takair]

For the front seal, prop will need to come off, old seal removed, cleaned up, new seal bonded and installed.  Key here is a good cleaning job so the glue holds.  There is a tool for the solid one.  Split is a little easier to install, but may leak more often if not done right.  Allow your mecahnic time to do it right.  Reinstall the prop with a new O'ring (often forgotten) and then safety wire.  Torquing and safetying the bolts takes some time due to the nature of the installation.  Ideally you should have two people for removal and installation of the prop (more labor).  You might be able to help your mechanic with this part to save cost.  It can be done with one, just a little harder.  I personally think 2.5 is a little optimistic, but I'm a little slower than some.  As Scott said, be sure that is where the leak is, it's alot of work if this is not it.  However, it is pretty obvious if the inside of the flywheel is really wet.  A little oil is normal, but it will not appear "fresh".  Good luck.

[scottfromiowa]

My 1966 M20 E started doing what you describe and escallated to putting mist on center third of windshield plexi.  I replaced two prop seals before properly identified as a case half separation.  The engine was high time and had only 30 hours on it in 20 years...hope yours is just a prop seal.  No big deal there...

[bnicolette]

When my mechanic took the cowl off last time to look things over, he cleaned the engine for the purposes of seeing exactly where things were coming from and told me to make sure I flew it a bit.  He wasn't sure if the oil by the mag was actually coming from there or not and also near the front of the engine.  However, he has been on vacation since the beginning of April and I have been doing a good bit of flying back and forth to work, so hopefully, we won't have to go through the cleaning process again with the oil sorta being everywhere.  But, if takes cleaning it again and running it just a bit, then that's what I'll do.

BTW, I have been addicted to this board ever since purchasing my Mooney.  I have been involved in other boards for cars, bikes, etc., but this board and the folks involved are just "first class".

Thanks all,

Brett

[Shadrach]

Quote: takair

For the front seal, prop will need to come off, old seal removed, cleaned up, new seal bonded and installed.  Key here is a good cleaning job so the glue holds.  There is a tool for the solid one.  Split is a little easier to install, but may leak more often if not done right.  Allow your mecahnic time to do it right.  Reinstall the prop with a new O'ring (often forgotten) and then safety wire.  Torquing and safetying the bolts takes some time due to the nature of the installation.  Ideally you should have two people for removal and installation of the prop (more labor).  You might be able to help your mechanic with this part to save cost.  It can be done with one, just a little harder.  I personally think 2.5 is a little optimistic, but I'm a little slower than some.  As Scott said, be sure that is where the leak is, it's alot of work if this is not it.  However, it is pretty obvious if the inside of the flywheel is really wet.  A little oil is normal, but it will not appear "fresh".  Good luck.

[rgpilot]

I had this happen to my 93 201. It turned out to be loose bolts on the engine case at the top. Tighten the bolts and the leak stopped.

[Kwixdraw]

Don't go gorilla on those case bolts, and do it with a torque wrench. 50 in./lbs. if my memory is correct. It's not all that much but there is only a thread and non hardening sealer in there for a gasket.

[Shadrach]

I second qwixdraws comments on torquing the case bolts. However, I believe the torque value to be higher. I don't have a mx manual with me, but I recall 25ft/lbs as being the correct number. That being said, it's not a lot of torque and they willl break easily if over tightened...

[Shadrach]

..

[bnicolette]

I am out on a trip now till next Wednesday, but my mechanic is going to try and look into it on Monday or Tuesday.  I'll let you know what he comes up with.  Wish I could be there to work along with him to see where it's coming from.  Oh well, gotta bring home the bacon so I can feed the Mooney.  :-)

 

Thanks again for all the thoughts.

[Kwixdraw]

Quote: Kwixdraw

Don't go gorilla on those case bolts, and do it with a torque wrench. 50 in./lbs. if my memory is correct. It's not all that much but there is only a thread and non hardening sealer in there for a gasket.

[TonyPynes]

Quote: Bnicolette

I am out on a trip now till next Wednesday, but my mechanic is going to try and look into it on Monday or Tuesday.  I'll let you know what he comes up with.  Wish I could be there to work along with him to see where it's coming from.  Oh well, gotta bring home the bacon so I can feed the Mooney.  :-)

 

Thanks again for all the thoughts.

[TonyPynes]

Quote: KSMooniac

Phllips XC + Camguard is a great combo.  I switched a couple years ago after running A/S since Aviation Consumer heartily endorsed it and have been happy.

Before taking things apart, I'd de-cowl and thoroughly degrease your engine, and then run it for a few minutes and see if you can spot the leak(s).  It could come from somewhere unexpected and then migrate out...  I learned that the hard way after doing some maintenance that required me to loosen the top, aft crankcase bolt so that I could move the ignition harness.  I neglected to tighten that bolt completely on re-assembly, and oil from that area managed to migrate forward and out of my cowl!  It was a surprise to me...

[KSMooniac]

My filler tube has been loose in the past, but never came out the front of my cowl.  It is a tricky part to safety-wire tight, at least for me (amateur).  Your F baffling/cowl configuration is different than my J, though, so perhaps it might be possible.

[TonyPynes]

I had my mechanic replace crankshaft seal and prop seal. Just to be sure since the prop had to come off anyway.

Will test flight Sunday to see if the leak is gone.

It is time for a 50 hour oil and oil filter change.

The previous owner had aeroshell 100 in it. I will search the forums for what everyone else runs. Also need to check out the air filter.I use K&N on my Harleys and I think I have seen they are approved for Mooney M20s. Anyone else use K&Ns?

[TonyPynes]

I will report on costs for the seals replacement when I get the bill but I expect it to come in at around 400 to 450 since I was quoted 375. (Nothing is ever what is estimated  - at least not in my world.)

[Guest]

Austin

 

I've used the K&N for years now and love it. You will see a slight performance increase plus the ease of cleaning. 

 

 

Ed

[jetdriven]

If its fown frequently use what you feel like.  If it sits 10 or more days at a time, use W100, W80, or XC with camguard.  The K&N filter is approved as a Challenger filter but i think it lets in more dirt than Donaldson or a Brackett.  Brackett is cheap but restricts airflow. We went with the Donaldson.

[TonyPynes]

Report on my oil leak:

Had new crankshaft seal and prop oil seal replaced.

Took it for a flight and still leaked. but Crankshaft seal is dry.

Mechanic now says it looks like it is coming from the front lower crankcase itself.

I asked them to check torque. i will then fly again.

The engine is recent overhaul with less than 50 hours.

I really hope this is a torque issue.

[MooneyMitch]

By all means Austin, yes, please do check the upper and lower case bolt/nut torque settings.  This did occur with Jolie's Maggie and it took a long time to discover the source.

We did the prop seal, the crankseal too with no relief.  It was indeed the case bolts.  How and why, I have no idea but it sure did the trick.

Please let us know.