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alpinelakespilot2000

Well Known Member
My oil dipstick tube came from Aerosport with a fiber washer. Should any teflon paste sealant or fuel lube be used in addition to the gasket?

(There are lots of threads in the archives about dipstick tubes leaking, but I can't find one that says whether any thread sealant should be used in addition to the gasket.)

Thanks.
 
Funny Steve, I was just looking at my un-installed dipstick tube yesterday and wondered the same thing.
 
From stories of these tending to leak I decided to go with something else. I purchased a section of 1/8" thick silicone rubber and cut a round gasket from it. 21 hours on the engine so far and no leaks. Didn't use any other sealant when installing.
 
I smeared a small amount of Permatex "Form-A-Gasket" on the gasket. No leaks in 17 years.
Don't put anything on the threads. They do not seal anything.
 
Mel said:
I smeared a small amount of Permatex "Form-A-Gasket" on the gasket.
Click to expand...

Ditto. Mine was initially installed with just the gasket, but eventually it loosened up and leaked a bit, even with the safety wire. Got a new gasket, smeared with some Permatex sealant (on the gasket, not threads), tightened up the safety wire... no more leaks.
 
The Real Gaskets...

Garage Guy said:
Part RG-72059 from http://www.realgaskets.com also works well.

--Paul
Click to expand...

...part looks a heck of a lot better than the very thin paper gasket Lycoming specifies.

rg-72059.jpg


It's also PMA for certified engines and an aviation bargain at only $3.

I think part of the problem is the very slight rotation as the dipstick is screwed on and off - there is just no give in the paper gasket - this one should have that extra little tolerance to stop is leaking.

Thanks for the link....:)
 
Two important considerations to prevent dipstick tube leaks.

1 sealant on the gasket and then very tightly safety wired with .041 safety wire. The safety wire must very pulled very tight so there is no possibility of the tube rotating. If it ever rotates even a little bit, the seal is broken and it will leak.

2 Do Not Over Tighten the dip stick. It gets even tighter after it has been heated and then cooled and makes it very difficult to remove at the next level check. This causes the tube to rotate and break the seal (see # 1 above).

The Real gasket would likely help with this a lot but I think the above points would still be valid
 
I used EZ Turn lubricant on all my fittings for fuel and brakes in the cabin. I hope that was the correct thing to use. Now I ready to install my quick drain in the gascolator. The instructions call for a thread sealant. What did you guys use for thread sealant?
 
rvbuilder2002 said:
Two important considerations to prevent dipstick tube leaks.

2 Do Not Over Tighten the dip stick. It gets even tighter after it has been heated and then cooled and makes it very difficult to remove at the next level check. This causes the tube to rotate and break the seal (see # 1 above).
Click to expand...

THIS IS SO TRUE............... Contact plus 30 degrees is enough. Look at the "O" ring at the top of the dip stick. If it is flat on the contact surface, It will grip the tube more aggressively. Change the "O" ring (hardware store item) and then tighten 30 degrees past contact and you will be good. If the tube still moves, then safety wire it again. Turn it really snug, but don't over do it.
 
SmittysRV said:
I used EZ Turn lubricant on all my fittings for fuel and brakes in the cabin. I hope that was the correct thing to use. Now I ready to install my quick drain in the gascolator. The instructions call for a thread sealant. What did you guys use for thread sealant?
Click to expand...
Hi Smitty - when you mean on the fittings, you mean on the pipe thread side, right? Nothing goes on the threads on the flared side.

Loctite makes a teflon paste specially for tapered pipe threads. It is recommended by Grove in their brake literature. It lubricates the threads as well as seals them. It is designed for exposure to petroleum like fuel or brake fluid. It comes in a pretty big white tube. I think it is Loctite 565.

Good luck,

dave
 
rvbuilder2002 said:
Two important considerations to prevent dipstick tube leaks.

1 sealant on the gasket and then very tightly safety wired with .041 safety wire. The safety wire must very pulled very tight so there is no possibility of the tube rotating. If it ever rotates even a little bit, the seal is broken and it will leak.

2 Do Not Over Tighten the dip stick. It gets even tighter after it has been heated and then cooled and makes it very difficult to remove at the next level check. This causes the tube to rotate and break the seal (see # 1 above).

The Real gasket would likely help with this a lot but I think the above points would still be valid
Click to expand...

Yep! My tube leaked at 5 hours TT.

I originally used fuel lube. Once it leaked I cleaned all that off and put on a little paste and tightened. Then as Scott said. install the safewire really taught so that it will prevent rotation.
 
Do Not Over Tighten the dip stick. It gets even tighter after it has been heated and then cooled and makes it very difficult to remove at the next level check. This causes the tube to rotate and break the seal (see # 1 above).
Click to expand...
My experience is no "sealant" needed - it the dipstick tube is tight, it doesn't leak ;)

To avoid doing it up too tight, rule at one place where I instruct (Extra 300s / Bulldogs) is DO NOT USE YOUR THUMB TO TIGHTEN DIPSTICK :eek: Use knuckles of next 2 fingers only... it's more than enough :) Works for me...

As an aside - we have a metal Superior Dipstick tube - I had to make up a special AL spanner to fit on the tube and (re)tighten where rule above had not been followed!

Andy
 
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