Oil filler tube gasket

[0TreeLemur]

Changed the oil in our C today.   While waiting for quarts to drain, I looked into why the oil filler tube is loose.   You experienced owners already know this, but the oil filler tube screws into the engine and is safety wired.  The safety wire on my aircraft had stretched or somehow loosened enough to allow the filler tube to rotate about 1/16 of a turn.

I clipped the old loose safety wire off, and replaced it with a nice tight new one.  Great.

This raises a question- it seems that there is a gasket there, can anyone point me to a replacement filler tube gasket for the mighty O-360?  Mine was showing signs of leakage. 

In all honesty, I haven't even started looking.  If someone can post a link to that gasket I'd appreciate it.

Thanks,

Fred

[N201MKTurbo]

Download the parts manual for your engine and find the gasket. Then Google the part number and order the gasket.

[PT20J]

Tube always comes loose eventually and the paper gasket leaks. It’s worse if you overtighten the dilstick. Better if you safety with .041 wire that doesn’t stretch as much.

Here’s the standard gasket https://www.aircraftspruce.com/catalog/eppages/superior08-00305.php

Some people swear by this one, but I haven’t tried it https://www.aircraftspruce.com/catalog/eppages/basegasket.php

Skip

 

[Skyland]

My dipstick tube was always coming loose with the standard Lycoming gasket.

This Real Gasket did the trick.  Nice seal on the silicone gasket and hasn't come loose at all.  Still safety wire it.

RealGaskets.com  RG-72059  Appears to be the same one from Spruce that Skip mentioned.  It works. 

And their silicone valve covers gaskets too.  Haven't had any leaks since installing them.

---Ken

[jetdriven]

You can also put an o-ring on it.  Then it stayed fixed for years 

[Lionudakis]

The REAL gaskets are the ticket to no more leaks!

[N201MKTurbo]

The secret to a leak free oil filler is not over tightening the dip stick. 
 

Just don’t let anybody else do it. They will always over tighten it, sometimes by a lot. Then you end up unscrewing the filler trying to get the dipstick out.

I have found spinning it till it stops, then 1/8 turn is all you need. It has never fallen out.

[N201MKTurbo]

You know the o ring or Real Gasket gasket will make your dipstick read 1/8 inch low….

[Shadrach]

When I was a kid, someone that I won’t name wiped the dip stick and laid it across the top of the motor mount after deciding to add a qt.. They added oil, closed the oil door and set off. We landed 3 hours later. Next morning we are preparing for departure and said pilot says “$hit, I forgot the dip stick”. There was no evidence of oil vapor nor leakage. Moral of the story…tightening down the dipstick isn’t really needed.

[Ragsf15e]

26 minutes ago, Shadrach said:

When I was a kid, someone that I won’t name wiped the dip stick and laid it across the top of the mount after deciding to add a qt.. They added oil, closed the oil door and set off. We landed 3 hours later. Next morning we are preparing for departure and said pilot says “$hit, I forgot the dip stick”. There was no evidence of oil vapor nor leakage. Moral of the story…tightening down the dipstick isn’t really needed.

I haven’t gone that far, but my old dipstick tube had very poor threads (the tube is plastic).  Bad enough that several times I landed and found the dipstick unscrewed and sitting lifted up half an inch on the tube.  Never any oil loss.  Got a new tube and tighten just barely past resistance, and all is well.

[EricJ]

I've had good experience with the Real gasket.   +1 to not overtighten the dipstick.    The Arrow I used to rent had a pair of pliers in the hatch because without fail somebody would tighten it so much you couldn't get it back off without tools.

 

[0TreeLemur]

During my first flight lesson in a C152 in 1981 my instructor admonished me "don't tighten the dipstick, just turn lightly until it stops turning and quit."   That's what I've always done.  This thing was loose when I bought the airplane almost 5 years ago.  It has finally risen to the top of my to-do list!

Thanks to everyone for your input.  I'll think try one of the silicone gaskets.  Extremely low cost/low risk at 0.007 AMUs. 

I venture to say that the sum-total of the input from the MS community to this simple question is far superior to looking up a part number and ordering a paper gasket.

Go MS!

[Skates97]

10 hours ago, Skyland said:

My dipstick tube was always coming loose with the standard Lycoming gasket.

This Real Gasket did the trick.  Nice seal on the silicone gasket and hasn't come loose at all.  Still safety wire it.

RealGaskets.com  RG-72059  Appears to be the same one from Spruce that Skip mentioned.  It works. 

And their silicone valve covers gaskets too.  Haven't had any leaks since installing them.

---Ken

Same experience, the standard gasket was always loose. The silicone one has been great. As others have mentioned don't overtighten the tube with the silicone gasket. I've found that just tightening the tube by hand and then putting safety wire is enough to keep it from leaking. The threads are very coarse which contributes to the problem with them coming loose.

[jetdriven]

11 hours ago, N201MKTurbo said:

You know the o ring or Real Gasket gasket will make your dipstick read 1/8 inch low….

Its about it 1/16 of an inch, but even at 1/8 of an inch how much oil quantity error  are we talking about here?