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Teflon tape on oil drain plug?

dbier99

Well Known Member
Doing our first oil change tonight and have received differing opinions - should we place a layer or two of teflon tape on the oil drain plug before reinstalling?
 
No.

No teflon tape on aircraft. Ever. I’ve been using Loctite 565, the (supposedly) latest and greatest thread lube/ sealant.
 
Even if used with extreme caution, Teflon tape can “extrude” under the pressure in threaded joints and send pieces into the process fluid. If lucky, it only blocks the filter element.
 
+1 Saf Air type drain

Works great., never an issue. Tired of dropping the plug in the oil bucket. You can also attach a hose to the end that directs the oil into a jug with a 3-inch screw cap.
 
I won't allow Teflon TAPE in my hangar at all. Liquid sealant sure, but tape never belongs on airplanes as mentioned. Too many chances of it coming loose and blocking something.
 
As I understand it, there is little to no room for Teflon tape in aviation.

There are approved sealers/paste for this purpose. Of course if it was me, I would ditch the plug and use a Saf Air type drain which will eliminate removing/installing the plug.

https://www.aircraftspruce.com/catalog/eppages/safOilDrainValves_07-00879.php
Appreciate the replies - and didn't use teflon tape! Will look into the Saf Air oil drain - but have been told that that these types of quick drains often/eventually seep. But am glad to hear you've had good luck with them so will reconsider.
 
Get a Fumoto quick drain valve. Install it with Loctite 567. Drill a small hole in the quick drain valve body and safety wire it in place and you are done. Get some 3/4" oil hose from your local auto parts store to hook up to the nipple when you want to drain the oil. The larger 3/4" size makes draining much quicker than the Safair drain. Oh, and the Fumoto is $65 less than the Safair. It also has a positive locking mechanism on the ball valve, so it won't open unless you press and turn the lever.
 
Ok...I have a question. :)

Why would a small piece of teflon tape be more dangerous if it got loose than a glob of teflon paste? I'm assuming the paste is insoluble in oil and could be very effective at plugging an oil passage.

The problem I've seen with the tape is improper application. If the tape is applied where NO tape extends past the end of the fitting it seems there wouldn't be any risk of a fragment getting loose. But I accept that sloppy application is probably common and the admonition to not use tape may be deserved.
 
What do all the Teflon tape haters use on your pitot-static fittings?

Not a hater, just have to ensure proper application. Teflon in any form is a great product. It purportedly had the lowest RT coefficient of friction of any solid, maybe still does. It has respectfully low chemical reactivity. I have no issues using it in the right application line a P/S. Having a piece loose in an engine can cause local lube starvation. Getting a piece loose in a hydraulic system can be even worse. Stated again, like many things it’s all about the application.

Edit = @ Sam. Threads can be extreme pressure areas. The material can flow under that pressure. It’s one of those things where the potential consequences can be very high versus the low probability of causing an issue.
 
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...

The problem I've seen with the tape is improper application. If the tape is applied where NO tape extends past the end of the fitting it seems there wouldn't be any risk of a fragment getting loose. But I accept that sloppy application is probably common and the admonition to not use tape may be deserved.

This was exactly my thinking as well. Someone - can't recall who - explained that one application of teflon tape done perfectly does not represent a risk, but when you remove the thing that's been sealed with teflon tape, the teflon pieces tend to get "everywhere". Again, if you then perfectly clean everything, it can be ok, but we're all just human, and it's easy to avoid this risk.
 
Get a Fumoto quick drain valve. Install it with Loctite 567. Drill a small hole in the quick drain valve body and safety wire it in place and you are done. Get some 3/4" oil hose from your local auto parts store to hook up to the nipple when you want to drain the oil. The larger 3/4" size makes draining much quicker than the Safair drain. Oh, and the Fumoto is $65 less than the Safair. It also has a positive locking mechanism on the ball valve, so it won't open unless you press and turn the lever.
I'm sold! Will install one at next oil change!
 
The bad thing with Teflon is the reduction of friction. you can very easily over torque the fitting, resulting in pulled threads or splitting the hole its going into. One Fire pump manufacturer I worked with voids the warranty if any teflon is found on their pumps. - Ben
 
Get a Fumoto quick drain valve. Install it with Loctite 567. Drill a small hole in the quick drain valve body and safety wire it in place and you are done. Get some 3/4" oil hose from your local auto parts store to hook up to the nipple when you want to drain the oil. The larger 3/4" size makes draining much quicker than the Safair drain. Oh, and the Fumoto is $65 less than the Safair. It also has a positive locking mechanism on the ball valve, so it won't open unless you press and turn the lever.

+1 - I have one of these on my new RV6, and have changed my oil twice. What I notice v.s. the SafeAir unit (other than price) is that - the oil flows out during draining quicker; the positive closure lock is very secure; and they offer a clamp made to secure the closure. I have also drilled holes to secure the drain, and the closure lever with safety wire if I choose.
 
Ok...I have a question. :)

Why would a small piece of teflon tape be more dangerous if it got loose than a glob of teflon paste? I'm assuming the paste is insoluble in oil and could be very effective at plugging an oil passage...

Thought someone with first hand knowledge would chime in. For the record, I'm a big fan of Tri-Flow since I first ran into it guessing thirty years ago.

Here is theory/pure conjecture on my part.

The lubricant proper is the Teflon. They used to use to term "Teflon Resin" in their marketing literature a while back. Now they use the term "micronized". Don't know if the Teflon particles have changed size throughout the products life. The binding/carrying agents in the oils, pastes, and sprays are petroleum based. The small amounts would most likely mitigate any compatibility issues (synthetic hydraulic fluids would probably be an issue). That said, any of the aforementioned that got lose in the process fluid would soon be broken down but the chemically non-reactive (d@mn near inert?) particles of Teflon would suspended in such and would migrate wherever the flows took it. As any liberated tape would stay in one piece, the chances of it fouling/blocking small passages is greater. From my personal experience, Teflon tape has stopped many tests and forced powerplants off line. Hydraulic systems that utilize servo valves are very susceptible to any contamination and (unauthorized use of) teflon tape was a common culprit. I would be very surprised if any service branch of airline allowed use of Teflon tape in their Hyd systems but there's always one.

Conjecture over

Hopefully someone with firsthand knowledge of some of this will weigh in.

Happy Friday and sorry for adding to the drift.
 
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Appreciate the replies - and didn't use teflon tape! Will look into the Saf Air oil drain - but have been told that that these types of quick drains often/eventually seep. But am glad to hear you've had good luck with them so will reconsider.

10 years on, no leaks from mine.
 
What do all the Teflon tape haters use on your pitot-static fittings?
Thread drift but whatever, this is a good question.
I agree that teflon tape has no place anywhere else in aircraft. But it seems common in P/S systems and I use it there. Right or wrong?
 
Thread drift but whatever, this is a good question.
I agree that teflon tape has no place anywhere else in aircraft. But it seems common in P/S systems and I use it there. Right or wrong?

I think the only issue is what we all freak out about whenever this subject comes up: i.e. teflon can migrate and has brought airplanes down when used in critical engine systems.

pitot static is a whole different thing. I've got no problem at all with teflon in that application. In fact, the Stein kit comes with teflon already applied to the pipe fittings, although I don't recall if its tape or paste.
 
Not all teflon tape is the same...... If you think you really need to use teflon tape, you may consider using YELLOW teflon tape.


I am only talking about using it on pitot static.... NOT fuel-oil fittings!!!!
 
P/S also a no no. Last time I had some instruments overhauled, there was a warning not to us teflon tape that was included in the paperwork.
 
Get a Fumoto quick drain valve. Install it with Loctite 567. Drill a small hole in the quick drain valve body and safety wire it in place and you are done. Get some 3/4" oil hose from your local auto parts store to hook up to the nipple when you want to drain the oil. The larger 3/4" size makes draining much quicker than the Safair drain. Oh, and the Fumoto is $65 less than the Safair. It also has a positive locking mechanism on the ball valve, so it won't open unless you press and turn the lever.

I have the quick drain valve it works awesome.
 
Fuel Pressure Gage Line Fitting

Along the same line here, I'm installing a new fuel pressure gage. Is some type of sealant/thread locker called for?

Seems like just screwing in the fuel pressure input line into the back of the instrument without securing it some way is asking for vibrations to maybe cause loosening over time and leaking fuel into the cockpit behind the instrument panel.

I really don't like messing with fuel lines, and I've never done this job before. Looks like a simple (ha ha) remove-and-replace, but the fuel line input is a thinker for me. Any suggestions will be appreciated.

RC
 
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Along the same line here, I'm installing a new fuel pressure gage. Is some type of sealant/thread locker called for?

Seems like just screwing in the fuel pressure input line into the back of the instrument without securing it some way is asking for vibrations to maybe cause loosening over time and leaking fuel into the cockpit behind the instrument panel.

I really don't like messing with fuel lines, and I've never done this job before. Looks like a simple (ha ha) remove-and-replace, but the fuel line input is a thinker for me. Any suggestions will be appreciated.

RC

I don't know what airplane you are working on, I don't expect it to be an RV. But if it is experimental, then purchase an electric fuel gage and mount the sender on the firewall or engine mount near the firewall and run a wire to the gage.
 
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