dipstick tube thread sealant?

alpinelakespilot2000 · #1 02-15-2010, 02:04 PM

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.

boom3 · #2 02-15-2010, 02:20 PM

Funny Steve, I was just looking at my un-installed dipstick tube yesterday and wondered the same thing.

trib · #3 02-15-2010, 02:32 PM

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.

tommylewis · #4 02-15-2010, 03:43 PM

I used proseal, 3 years and no leaks yet.

alpinelakespilot2000 · #5 02-15-2010, 06:05 PM

So, back to the question...

Quote:

Originally Posted by alpinelakespilot2000

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?

What is standard practice here?

Mel · #6 02-15-2010, 06:32 PM

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.

jbDC9 · #7 02-15-2010, 08:24 PM

Quote:

Originally Posted by Mel

I smeared a small amount of Permatex "Form-A-Gasket" on the gasket.

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.

Garage Guy · #8 02-15-2010, 08:39 PM

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

--Paul

az_gila · #9 02-15-2010, 11:38 PM

Quote:

Originally Posted by Garage Guy

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

--Paul

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

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....

rvbuilder2002 · #10 02-15-2010, 11:49 PM

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