• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

O-235 Oil Leak ID Line-Up!!

Philly5G

Registered User
England
Do any of you O-235 drivers recognise this oil leak pattern and hopefully know the source of it please?!! As you can see, it’s either right above or just behind and between the generator and starter motor.

A double whammy is that there’s no oil filler extension on the dipstick mount and pouring oil in is a PITA and takes ages!IMG_4078.JPGIMG_4079.JPGIMG_4081.JPG! What have other people done to either devise a quick fill method, or extend the filler?

THANK YOU!!!

Philly


Sent from my iPhone using SuperCub.Org mobile app
 

Attachments

  • IMG_4078.JPG
    IMG_4078.JPG
    464.5 KB · Views: 261
  • IMG_4079.JPG
    IMG_4079.JPG
    180.5 KB · Views: 341
  • IMG_4081.JPG
    IMG_4081.JPG
    124.9 KB · Views: 345
Last edited:
BRILLIANT!! Thanks!! Sounds like the Push Rods are the most likely suspects so far :)


Sent from my iPhone using SuperCub.Org
 
That sounds likely, but if not clean it up good and look for leaking between the case halves at the bottom of the engine. Not as usual in an 0235 as some others, but look for it. A case crack near the starter is not unheard of either. Total time on the engine?
 
That sounds likely, but if not clean it up good and look for leaking between the case halves at the bottom of the engine. Not as usual in an 0235 as some others, but look for it. A case crack near the starter is not unheard of either. Total time on the engine?

Total engine time around 1700 hours. Not jumping to the worse scenario yet, but case crack does sound very scary :(
 
Did you check the oil return hose and clamps? Those buggers love to leak all over the place!

Please take more pictures, but clean it up really well, then fly it for 20 minutes so we can get a better view.
 
Gravity is showing you where collected oil drips. With a pressure cowl that oil can come from someplace else. Get a sprayer and some Stoddard solvent and give the engine a bath, then watch for seeps and drips.
 
Gravity is showing you where collected oil drips. With a pressure cowl that oil can come from someplace else. Get a sprayer and some Stoddard solvent and give the engine a bath, then watch for seeps and drips.

Really good point, thank you! The aircraft has been stood for a lot of the time over the last few months, while I’ve been fixing various things, interspersed with test flights and I haven’t noticed any oil drips on the ground and it does seem that the oil only comes out in flight.

I also gave the cowls a really good clean when I originally took them off and oil then only appeared after the first flight after this. Any more clues in this?


Sent from my iPhone using SuperCub.Org mobile app
 
There’s a sign on one of the machines in my shop that says “A Clean Machine is a Trouble Free Machine”. There’s a lot of truth to that.
 
Philly, For what it's worth. It's been a long time since I've been actively involved with the O-235 engines. However it is my recollection that they would soldier on forever. That the only reason that they were torn down for overhaul after well more than 2000 hours was that the oil leaks became too numerous. Usually even then there was nothing mechanically wrong with them.
 
There’s a sign on one of the machines in my shop that says “A Clean Machine is a Trouble Free Machine”. There’s a lot of truth to that.

Thanks Stewart I COMPLETELY agree with that and a large part of the joy of doing the work on the PA-12 is cleaning it up, including the crud behind all the panels and the ton of work I did on the tail brace wires to make them look like new :)

Just cleaning the inside of the cowls took ages, to remove the (years? of) dried on oil and crud and now the engine is very inconveniently depositing more onto my nice clean surfaces!!! On a related point, I replaced the valve cover gaskets some months ago with silicon ones as suggested on the forum, but although the port side is now completely free of spatter after flying, the starboard side still has it, although less than before, any ideas?
 
Philly, For what it's worth. It's been a long time since I've been actively involved with the O-235 engines. However it is my recollection that they would soldier on forever. That the only reason that they were torn down for overhaul after well more than 2000 hours was that the oil leaks became too numerous. Usually even then there was nothing mechanically wrong with them.

THANK YOU for that SW!!! A very positive message to start the day with!! In the flying and testing I'm doing, it seems that the engine/aircraft are performing pretty much how they should, so the 1700 engine hours don't seem to have reduced its performance much!! :)
 
BRILLIANT!! Thanks!! Sounds like the Push Rods are the most likely suspects so far :)


Sent from my iPhone using SuperCub.Org

OK, I'm back on the oil leak hunt after doing a load of work and then, in the 2 hour shake down flight (everything worked!!) the engine lost just under 2 quarts of oil, maybe 1.75 quarts.NILKB8pQRuegQGQonJ8vdw.jpg6ENE7JcvQieIOsGTdVEQrA.jpg I looked at the pushrod tubes and the front starboard one is leaking and I've attached a picture. I'm about to order replacements, but could this leak account for such a large oil loss?
 

Attachments

  • NILKB8pQRuegQGQonJ8vdw.jpg
    NILKB8pQRuegQGQonJ8vdw.jpg
    187 KB · Views: 268
  • 6ENE7JcvQieIOsGTdVEQrA.jpg
    6ENE7JcvQieIOsGTdVEQrA.jpg
    174.7 KB · Views: 307
That amount of oil loss would have the engine swimming in oil. What does the inside of the exhaust pipe look like? Wet? That is only a few drops of oil on the front pushrod tube.
 
Clean up the engine with solvent and then spray on some talcum power in spray can around the push rod tubes, engine case split line and around the cylinder bases. Go fly for a few minutes, land and look and any leak will show right up.

Jim
 
When I got back from the trip there was black oil running back from the starboard of the cowl over the boot cowl and a bit more added to the oil lying under the engine in the lower cowl, but certainly not swimming in oil :) What I have noticed though, is new/clean looking “jellified” oil collecting in the drip tray and continuing to drip out, I THINK from the clear tube that pokes out the back of the cowl (oil overflow?) pic attached


Sent from my iPhone using SuperCub.Org mobile appIMG_4368.JPG
 

Attachments

  • IMG_4368.JPG
    IMG_4368.JPG
    204.1 KB · Views: 277
Philly, I do not see the equivalent of 1.75 quarts of oil leakage over a two hour period in your picture. Yes you are leaking some, though I suspect that you are burning most of it. What is inside your exhaust tailpipe? Wet, dark, oily?
 
Thanks!! That pic wasn’t after the 2 hour trip, but the picture would look pretty much the same, with just black trickles of oil on the starboard panels at the bottom.

Does burning the oil mean it’s going past the piston rings? The plugs DO get pretty oily and I need to clear them by leaning out the mixture immediately after start up and then running for 30-45 seconds at high power before the mag drops are in tolerance at 100rpm drop

I’ll check the exhaust when at the airfield later this week, but any thought on the clean looking “jellified” oil that’s still leaking out?


Sent from my iPhone using SuperCub.Org
 
Just a guess from across the pond. It appears that the oil control rings may be tired allowing oil into the combustion chambers while the engine is running which would produce black wet spark plugs and a oily dirty exhaust pipe. The plugs getting oily and fouled at start up indicates residual oil in the combustion chamber from the oil control rings and/or worn valve guides. Where is the jellified oil coming from? The breather pipe? This would also be an indication of piston ring wear pressurizing the crankcase. What is the total time on the engine since overhaul? This is a symptom of a high time engine. When you pull the prop through by hand does it turn through compression easily or does it have a lot of resistance? Easily = worn rings and/or leaky valves.
 
Back
Top