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tx_jayhawk

Well Known Member
Are people putting teflon paste (or other) on the threads on the dipstick tube that screws into the engine (O-360)?

I seem to have a very slight leak there, and I wonder if it needs thread sealant in addition to the washer that is there.

Thanks,
Scott
 
This area is typical for seepage from what I have seen. I attribute it mainly to folks over tightening their oil fill cap and every time you take the cap off it tends to loosen the tube, especially if you didn't get the safey wire good-n-tight.

I use tight-seal on the gasket only, the treads are so coarse that I doubt putting sealant on them would do much good.
 
I have used Proseal on all my Lycoming dip stick tubes. Make sure everything is totally free of oil residue and coat the gasket and upper part of the threads. Tighten tube and safety wire and wait 3 to 5 days before running the engine. No more leaks or loose tube for years!

On another note, most folks tighten the dip stick too hard. When they have to unscrew it a lot of torque is required to break it loose.

Martin Sutter
Building and flying RV's since 1988
EAA Technical Counselor
 
Thanks for tip Martin. I have plastic tube and it's always wet there. I change gaskets nothing helped. Will Proseal tomorrow.
 
Gil,
I have something similar local A&P gave me a while ago. Still seeps, slower but seeps. Maybe it has something to do with plastic/metal combo expansion. You can not overtighten plastic tube you will strip the threads. I even used red RTV before didn't help. I think the proseal is a great idea. Will post the results.
 
I've used red RTV and it seems to work, but obviously not for Vlad. Rather than the permanent seal of pro-seal, another option is an o-ring. Once compressed and then safety-wired, shouldn't leak.

greg
 
Greg,
Basically it's the same idea of custom profiled o-ring out of proseal. As Martin mentioned only top threads will be sealed. This way it's not permanent and could be easy to remove.
 
My engine has a metal tube, not plastic. I'm not sure if it's a Superior innovation or not but I like it and it does not leak.
 
Really the biggest problem here is overtightening the dipstick and then the effort to loosen the dipstick in return loosens the tube. A new gasket, with permatex gasket sealer and then a TIGHT wire tie should solve the problem IF you do not overtighten the dipstick. :)
 
Reiley I made that mistake over tightening and probably tube came loose again. This was before


dipstickbefore.jpg



and this how it looks now. No more leaks I hope.


dipsticktubesealing.jpg
 
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