Leaking through bolts on O360

[Pixair]

Lower front thru bolt on Lyc. O360 A1A leaking through the threads.

Also a couple of parting seam bolts and sump attach bolts.

Anybody have a sure fire method to reduce the leakage?

Engine TT:675 Hours since IRAN ~475 three years ago. Runs great and flown most week days.

 

[Jetmart]

Not a sure way but worked for me for a couple sump and top case bolts. This was recommended by an AME.

Pull the bolt and clean hole and bolt extremely well using alcohol. I used a Q-tip to clean out the hole in the sump. Then pack the hole and cover the bolt with Permatex Aviation Form-A-Gasket. Use lots! Wait a couple of minutes, or as directed by the label, and then reassemble. Clean off excess.

https://www.permatex.com/products/g...tion-form-a-gasket-no-3-sealant-liquid-16-oz/

This may work if it is truly leaking through the bolt and not the gasket above the bolt.

.

 

[Pixair]

They are leaking thru the the threads, not the gasket.

Thanks for the info.

 

[lr172]

Is this a WD or ND engine. Which through bolt? Is this the one way up front just aft of the front oil seal or the shared bolt that secures cyl 1 & 2? The one up front is not really considered a through bolt; that term generally refers to cylinder hold down bolts.

 

[Pixair]

WD engine.

It is actually the lower front through bolt, location changed in 1st post to correct location.

It is one of the 1/2" bolts that goes through a cylinder base on one side of the engine and through a spacer on the other side. It is leaking on the spacer side (left). Drips on to the aft end of the starter.

It is not one of the smaller bolts just aft of the crankshaft seal.

Picture is rotated 90* left. Sorry.

 

[pecanflyboy]

Try Loctite 290 wicking threadlocker. This helped me. Ultimately, I discovered that my breather was pressurizing the case, pushing out through several places. Check your breather line, and sure it is venting the case and not finding high pressure.

 

[Pixair]

Thanks for the breather idea...headed to the hangar now, will check it.

 

[jrs14855]

Sump

Check the torque on the sump bolts. If it is below spec I suggest the following.
Torque the bolts to the proper torque. Now remove one bolt, install a new star washer and retorque. Repeat on all fasteners one at a time.
If there is still leakeage remove the sump, clean surfaces and install a new gasket coated on both sides with a thin layer of hylomar. New lock washers again.
The case split leak is probably improper procedure applying the sealant and silk thread if used.
the preferred procedure would be to remove the paint, clean and apply a bead of fuel tank sealer.

 

[Taltruda]

Try Loctite 290 wicking threadlocker. This helped me. Ultimately, I discovered that my breather was pressurizing the case, pushing out through several places. Check your breather line, and sure it is venting the case and not finding high pressure.

Another option is the Antisplat oil breather system that applies a slight vacuum to the crankcase.. eliminates all leaks I hear..